CN1711500A - Nonlinear optical fiber and optical signal processing apparatus using the optical fiber - Google Patents

Nonlinear optical fiber and optical signal processing apparatus using the optical fiber Download PDF

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Publication number
CN1711500A
CN1711500A CN 200380103083 CN200380103083A CN1711500A CN 1711500 A CN1711500 A CN 1711500A CN 200380103083 CN200380103083 CN 200380103083 CN 200380103083 A CN200380103083 A CN 200380103083A CN 1711500 A CN1711500 A CN 1711500A
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optical fiber
fuse
wavelength
covering
place
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广石治郎
宫部亮
杉崎隆一
熊野尚美
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Furukawa Electric Co Ltd
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Furukawa Electric Co Ltd
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  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)

Abstract

An optical fiber excellent in nonlinearity, especially an optical fiber having a low dispersion stable in a wide wavelength region near 1550 nm and a high nonlinearity characteristic are disclosed. An optical signal processing device using this optical fiber, especially an optical wavelength converter and a pulse compressor are disclosed. The optical fiber comprises a core and a clad provided around the core. The optical fiber is characterized in that the dispersion slope at 1550 nm wavelength is in the range from -0.01 to 0.01 ps/nm<2>/km, the absolute value of the dispersion at 1550 nm wavelength is in the range below 10 ps/nm/km, and the nonlinearity coefficient is in the range above 30x10<-10>/W. Further, another mode of an optical fiber having a polarization holding characteristic, a low loss, a high optical signal process efficiency, and a high nonlinearity is disclosed.

Description

Nonlinear optical fiber and adopted the light signal processing device of this optical fiber
Technical field
The present invention relates to non-linear outstanding optical fiber and adopted the light signal processing device of this optical fiber.
Background technology
In recent years, the high speed, high capacity, the long distance that more and more require light signal to transmit transmitted, thereby need find the high speed of the processing speed that realizes light signal and the signal processing technology that long distance transmits.
As a kind of light signal treatment technology, can enumerate that to be used for converting optical signals be electric signal, the electric signal that conversion is gone out carries out signal Processing, makes it revert to the method for light signal once more., with specially light signal being become electric signal, again it is reverted to the processing of light signal in this method, thereby be not suitable for the high speed signal processing.
By contrast, also has the full light signal treatment technology of under the state of light, handling light signal.This treatment technology does not become electric signal to light signal, but light signal is directly handled as light signal, thereby can carry out high-speed optical signal and handle.
In the full light signal treatment technology, the favourable method that is used in the nonlinear optical phenomena that produces in the optical fiber that transmits light signal, or utilize the method etc. of the non-linear phenomena that produces in the optical waveguide that constitutes by non-linear high material.
The full light signal treatment technology of the nonlinear optical phenomena that utilization produces in the former optical fiber can carry out high speed processing, can also reduce loss simultaneously, thereby be paid close attention to especially in recent years.As the non-linear phenomena that in this optical fiber, produces, can enumerate four ripples mix, from phase modulation (PM), cross-phase modulation, Rayleigh (Block リ ュ リ ァ Application) scattering etc.Wherein disclose the wavelength conversion that utilizes four ripples to mix, and utilized light signal treatment technologies such as pulse compression from phase modulation (PM), wave shaping.
It is to have imported the above light time of 2 wavelength in the optical fiber that four ripples mix, because non-linear phenomena, according to specific rule, the phenomenon that the light of new wavelength produces.Above-mentioned light signal treatment technology is the phenomenon that will utilize the light generation of this new wavelength in wavelength conversion.Also have, the wavelength conversion that has utilized this four ripple to mix has the advantage that can carry out wavelength conversion to a plurality of signal wavelengths in the lump.
Also have, utilize from phase modulation (PM) or cross-phase modulation, the waveform that has made to variation in transmission carries out shaping, can grow the full light signal that distance transmits is treated as possibility.
But, for applications exploiting this what is called four light in optical fiber mix or from the so-called wavelength conversion of the non-linear phenomena of phase modulation (PM), the light signal treatment technology of wave shaping, as optical fiber, just must be the optical fiber that can significantly cause non-linear phenomena, promptly have the optical fiber of high non-linearity.
As optical fiber, have by the spy and open the optical fiber that 2002-207136 communique (patent documentation 1) proposes with high non-linearity.
Figure 14 of above-mentioned patent documentation 1 and Figure 16 have provided all characteristics at the wavelength 1550nm place of this optical fiber in detail.
Summary of the invention
Dispersion values
, for above-mentioned patent documentation 1 disclosed optical fiber, the chromatic dispersion gradient at wavelength 1550nm place is-0.267ps/nm 2/ km～+ 0.047ps/nm 2/ km, its deviation is very big, and dispersion values also be-103.2ps/nm/km～+ 3.3ps/nm/km, its lower limit reaches the great value that absolute value is 103.2ps/nm/km.
That is,, can not provide stable and dispersion values and the little optical fiber of chromatic dispersion gradient for wavelength 1550nm.Therefore, can not be provided at the nearby low optical fiber of dispersion values in the wide wavelength region may of wavelength 1550nm.
To this, the 1st purpose of the present invention is to be provided at wavelength 1550nm and nearby has high non-linearity characteristic and the optical fiber stable, that dispersion values is low in the wide wavelength region may.Also be to provide the light signal processing device that uses this optical fiber.
The polarized wave retentivity
Utilize the light signal of high non-linearity characteristic and non-linear phenomena to handle the appreciable impact that is subjected to the polarized wave state.Therefore, the polarized wave retention performance of the optical fiber of use also is important.
High non-linear and have the optical fiber of polarized wave retention performance as having, there is the polarized wave that proposes by above-mentioned patent documentation 1 to keep optical fiber.
Keep optical fiber for this polarized wave, Figure 15 of above-mentioned patent documentation 1 represents its cross-sectional view, and Figure 16 represents its characteristic value.
Keep optical fiber for disclosed polarized wave in the above-mentioned patent documentation 1, the stress that is located at the fuse both sides is paid position component, and particularly, two stress are paid parts to the position of fuse or both intervals, for which kind of degree is just passable etc., does not clearly provide.Therefore, when making this polarized wave maintenance optical fiber, the adjustment of polarized wave cross-talk (Network ロ ス ト one Network) and beat long (PVC Yi ト Long) just is difficult to, and this is the problem that exists.Particularly, existence is difficult to make the polarized wave cross-talk to become the problem of the allowable value of hope.
To this, the 2nd purpose of the present invention is easily to make, provide the little value of polarized wave cross-talk for wishing, and non-linear outstanding, and the polarized wave that is suitable for utilizing the light signal of nonlinear optical phenomena to handle keeps optical fiber.Also be to provide the optical wavelength changer that uses this polarized wave to keep optical fiber.
Loss
The optical fiber that can significantly cause non-linear phenomena can be by increasing the nonlinear constant n of optical fiber 2/ Aeff (n 2: nonlinear refraction rate coefficient, Aeff: net sectional area) obtain.The increase nonlinear constant can pass through the high material of use nonlinear refractive index as the optical fiber constituent material, or reduces the mode field (モ one De Off ィ one Le De) of optical fiber, or the density that improves the light that transmits realizes.
It with the quartz glass covering that the essential structure of the optical fiber of principal ingredient comprises the fuse that is made of the silica glass that has improved refractive index by doped germanium and is located at the fuse periphery, is made of the silica glass lower than fuse refractive index.
The amount of the germanium that mixes in the silica glass is many more, and the nonlinear refractive index of silica glass is just high more, and refractive index is also high more.Also have, increase the refringence of fuse and covering, just can reduce the mode field footpath.Therefore, highly doped germanium in fuse just can improve the nonlinear refractive index of fuse and reduce the mode field footpath, thereby can obtain to have the optical fiber of high nonlinear constant.
But, improve its nonlinear refractive index and reduce mode field by highly doped germanium in fuse and directly obtain the high optical fiber of nonlinear constant, the loss of optical fiber will significantly uprise, and this is the problem that produces.Generally speaking, doped germanium in optical fiber will become greatly in the loss of the optical fiber of wavelength 1550nm band, and particularly in fuse during highly doped germanium, the increase of the loss of optical fiber is significant.
The loss of optical fiber uprises, even the nonlinear constant height, because big loss, the performance efficient of non-linear phenomena also can variation.This point is illustrated according to following formula (1), (2).
The nonlinear phase skew Φ NL in phase modulation (PM) as the nonlinear parameter of expression is represented by following formula (1).
ΦNL＝(2π/λ)·(n 2/Aeff)·I·Leff?????????????????????(1)
In the formula, n 2Be the nonlinear refractive index of optical fiber, Aeff is the net sectional area of optical fiber, and I is a light intensity, and Leff is the effective length of optical fiber.
In above-mentioned formula, n 2/ Aeff is a nonlinear constant.
Also have, effective length Leff is represented by following formula (2).
Leff＝[1-exp(-aL)]/a?????????????????????????????????(2)
In the formula, L is the length of optical fiber, and a is the loss of optical fiber.
By above-mentioned formula (1), (2) as can be known, it is big that the loss of optical fiber becomes, and the effective length of optical fiber just shortens, and the nonlinear phase skew also diminishes.
Therefore, the optical fiber as using in the light signal processing that utilizes the non-linear phenomena in the optical fiber will have high nonlinear constant, and necessary loss is low., this have high nonlinear constant and the low optical fiber of loss, do not find so far.
In view of the foregoing, the 3rd purpose of the present invention is to provide the optical fiber that has high nonlinear constant and low loss simultaneously.
Efficient
Have again, for the light signal that effectively utilizes non-linear phenomena is handled, length, nonlinear constant, wavelength and the mutual relationship thereof of the absolute value of necessary consideration wavelength dispersion value, bending loss, loss, optical fiber.Considering their mutual relationship, the optical fiber of the light signal processing that can effectively utilize non-linear phenomena is provided, is the 4th purpose of the present invention.
General purpose of the present invention is, takes all factors into consideration above-mentioned several characteristic, and the light signal optical fiber of handling and the light signal processing device that uses this optical fiber that are suitable for utilizing non-linear phenomena are provided.
Disclosure of an invention
The optical fiber of the 1st side of the present invention is characterised in that, the chromatic dispersion gradient at wavelength 1550nm place is-0.01～0.01ps/nm 2/ km, preferably-0.005～0.005ps/nm 2/ km, the absolute value of the chromatic dispersion at wavelength 1550nm place is below the 10ps/nm/km, and the nonlinear constant at wavelength 1550nm place is 30 * 10 -10More than/the W, preferably 40 * 10 -10More than/the W.
Optical fiber according to such formation, just the wide wavelength region may of wavelength 1550nm can comprised, for example, S-band (1460～1530nm), C-band (1530～1565nm), L-band (provides the change of dispersion values to reduce, and the little optical fiber of the absolute value of chromatic dispersion in 1565～1625nm).
Also have, to the use wavelength of wide wavelength region may, dispersion values can significantly not change, and can carry out the light signal of various wavelength in 1 optical fiber and handle.Also have, chromatic dispersion gradient is-0.01～0.01ps/nm 2/ km, preferably-0.005～0.005ps/nm 2/ km, in wide wavelength region may the change of dispersion values little, can utilize the good light signal of nonlinear optical phenomena to handle.
By the way, the absolute value of chromatic dispersion gradient is 0.01ps/nm 2/ km is above, and to wavelength 1550nm different wave length nearby, it is big that the change of dispersion values becomes relatively, just no longer is suitable for transmitting at the WDM of wide wavelength region may.
Also have, nonlinear constant is 30 * 10 -10More than/the W, preferably 40 * 10 -10More than/the W, just can obtain to have high nonlinear optical fiber.
Also have, among the embodiment of the optical fiber of above-mentioned the 1st side, be characterised in that cutoff wavelength λ c is below the 1450nm, net sectional area Aeff is 12 μ m 2Below, 10 μ m preferably 2Below.
According to the optical fiber of such formation, can make optical fiber come work as single-mode fiber.Like this, because cutoff wavelength λ c is below the 1450nm, thereby optical fiber of the present invention can be used for comprising the wide band of S-band, C-band and L-band.
Also have, because net sectional area Aeff is 12 μ m 2Below, 10 μ m more preferably 2Below, thereby can obtain high nonlinear constant.
Herein, nonlinear constant is represented by following formula (1).
In addition, in following formula (1), λ represents to measure wavelength, n 2Nonlinear refractive index in the expression optical fiber, Aeff represents the net sectional area of optical fiber.
Nonlinear constant=n 2/ Aeff (1)
According to following formula (1),, must increase nonlinear refractive index n for increasing the nonlinear constant of optical fiber 2, or reduce net sectional area Aeff.
Herein, n 2Be value, be not easy to increase by the material decision.Thereby the value that reduces the net sectional area Aeff of optical fiber as far as possible is real.
To this, according to the optical fiber of claim 4 of the present invention or claim 5 record, the net sectional area Aeff that makes optical fiber is 12 μ m 2Below, 10 μ m preferably 2Below, just can obtain higher nonlinear constant.Particularly, the nonlinear constant that can obtain wavelength 1550nm place is 30 * 10 -10More than/the W, even 40 * 10 -10The optical fiber of the value that/W is above.
Also have, among the embodiment of the optical fiber of above-mentioned the 1st side, be characterised in that the absolute value of the chromatic dispersion at wavelength 1550nm place is below the 5ps/nm/km.
According to the optical fiber of such formation, can more certain acquisition in using wavelength, have higher nonlinear optical fiber.
Have again, among the embodiment of the optical fiber of above-mentioned the 1st side, the amplitude of fluctuation than the dispersion values of length direction of the optical fiber of the random wave strong point in wavelength 1510～1590nm (maximal value and minimum value poor) 1 optical fiber use in the long total length to 1ps/nm/km below, preferably below the 0.2ps/nm/km, so just can be used for wavelength shifter etc. effectively.
, in the present invention, the amplitude of fluctuation of above-mentioned dispersion values is meant the optical fiber total length for practical length, the amplitude of fluctuation of the dispersion values of being measured by the chromatic dispersion distribution measurement instrument.The distribution measuring of CHROMATIC DISPERSION IN FIBER OPTICS value can be measured by the chromatic dispersion distribution measurement instrument that utilizes the mode that for example Mollenauer worked out.
Also have, among the embodiment of the optical fiber of above-mentioned the 1st side, be characterised in that to have: the 1st fuse has the refractive index higher than pure silicon stone; The 2nd fuse is located at the periphery of the 1st fuse, has the refractive index lower than pure silicon stone; And covering, periphery at the 2nd fuse, lower than the 1st fuse refractive index, than the 2nd fuse refractive index height, the outer diameter D 1 of above-mentioned the 1st fuse is 2～5 μ m, the ratio D1/D2=Da of the outer diameter D 1 of above-mentioned the 1st fuse and the outer diameter D 2 of above-mentioned the 2nd fuse is more than 0.3, below 0.8, more preferably more than 0.4, below 0.7.Herein, pure silicon stone is meant the silica of the adulterant of refractive index adjustment usefulness such as not fluorine-containing and germanium.
According to the optical fiber of such formation, the ratio D1/D2=Da of the outer diameter D 1 by adjusting above-mentioned the 1st fuse and the outer diameter D 2 of above-mentioned the 2nd fuse just can obtain the low optical fiber of chromatic dispersion gradient.That is, optical fiber is made this structure, it is little just can to obtain net sectional area Aeff, and cutoff wavelength λ c is also low, and the little optical fiber of the value of chromatic dispersion gradient.
Have again, among the embodiment of the optical fiber of above-mentioned the 1st side, be characterised in that, the specific refractivity difference Δ 1 of above-mentioned the 1st fuse and covering is 2.0～5.0%, preferably 2.4～4.0%, the specific refractivity difference Δ 2 of above-mentioned the 2nd fuse and covering is-1.4～-0.7%, preferably-1.2～-0.8%.
According to the optical fiber of such formation, just can stablize high non-linear, low chromatic dispersion gradient of manufacturing and cutoff wavelength λ c is the following optical fiber of 1450nm, and keeps high productivity.
In addition, among the embodiment of the optical fiber of above-mentioned the 1st side, be characterised in that the refractive index profile shape of above-mentioned the 1st fuse is α curve, α is more than 3.0, preferably more than 6.0.
According to the optical fiber of such formation, just can obtain to reduce chromatic dispersion gradient and can reduce net sectional area Aeff, non-linear high optical fiber.
Light signal processing device of the present invention is characterised in that, has adopted the optical fiber of above-mentioned the 1st side.
According to this light signal processing device, can carry out the light signal processing of stable performance in wide wavelength coverage.
Have again, among the embodiment of above-mentioned light signal processing device, be characterised in that, be optical wavelength changer.According to this optical wavelength changer, just can provide the optical wavelength changer of wavelength conversion good drawing property.
In addition, among the embodiment of light signal processing device, be characterised in that light signal processing device is a pulse shortener.According to this pulse shortener, just can provide pulse compression outstanding pulse shortener.
Thereby just can be provided at the stable and low optical fiber of dispersion values in the wide wavelength region may that comprises wavelength 1550nm.The light signal processing device that has adopted this optical fiber can also be provided, be specially outstanding optical wavelength changer of performance and pulse shortener.
The optical fiber of the 2nd side of the present invention is to have fuse, be located at the covering of periphery of this fuse and the polarized wave that 2 stress being located at the both sides of above-mentioned fuse are paid the quartz glass class of parts keeps optical fiber, it is characterized in that, the nonlinear factor at wavelength 1550nm place is more than the 15/W/Km, cutoff wavelength is below the 1500nm, the chromatic dispersion at wavelength 1550nm place is-9ps/nm/km to 9ps/nm/km that the chromatic dispersion gradient at wavelength 1550nm place is 0.029ps/nm 2Below/the km, and the polarized wave cross-talk at wavelength 1550nm place be-below the 20dB/100m.
Keep optical fiber according to the polarized wave of such formation, just can easily make the polarized wave of polarized wave cross-talk in the permissible range of hope and keep optical fiber, and the optical fiber of non-linear outstanding, the light signal processing that is suitable for utilizing nonlinear optical phenomena can be provided.
Among the embodiment of the optical fiber of above-mentioned the 2nd side, above-mentioned fuse is made of the 1st fuse that is positioned at central part and the 2nd fuse that is located at the periphery of the 1st fuse, above-mentioned the 2nd fuse has than the low refractive index of above-mentioned the 1st fuse, above-mentioned covering has than above-mentioned the 2nd fuse height and than the low refractive index of above-mentioned the 1st fuse, above-mentioned the 1st fuse is more than 1.8% to the specific refractivity difference Δ 1 of above-mentioned covering, above-mentioned the 2nd fuse is below-0.1% to the specific refractivity difference Δ 2 of above-mentioned covering, the ratio R/D1 that above-mentioned stress is paid the diameter D1 of the interval R of parts and above-mentioned the 1st fuse is 2.5 to 10, and the ratio D1/D2 of the diameter D1 of above-mentioned the 1st fuse and the diameter D2 of above-mentioned the 2nd fuse is 0.3 to 0.8.
Also have, among the embodiment of the optical fiber of above-mentioned the 2nd side, be characterised in that, the ratio R/D1 that above-mentioned stress is paid the diameter D1 of the interval R of parts and above-mentioned the 1st fuse is 2.5 to 3.7.
Like this, R/D1 is 2.5 to 3.7, just can more positively obtain the abundant little polarized wave cross-talk in desired value, is preferred.
Among the embodiment of the optical fiber of above-mentioned the 2nd side, be characterised in that the interval R that above-mentioned stress is paid parts is 7 μ m to 17 μ m.
Regulation two stress that are positioned at the fuse both sides are paid the interval R of parts like this, just can be more really and easily be manufactured on the interior little optical fiber of polarized wave cross-talk of desired value.
Among the embodiment of the optical fiber of above-mentioned the 2nd side, be characterised in that cutoff wavelength is below the 1400nm, the chromatic dispersion gradient at wavelength 1550nm place is 0.019ps/nm 2Below/the km, the beat at wavelength 1550nm place is long for below the 5mm, and the bending loss of the diameter 10mm at wavelength 1550nm place is below the 0.1dB/m.
Optical fiber according to such formation, just can easily make not only the long also polarized wave in the permissible range of hope of polarized wave cross-talk but also beat and keep optical fiber, and the optical fiber that can provide non-linear light signal outstanding, that be suitable for utilizing nonlinear optical phenomena to handle.
Also have, among the embodiment of the optical fiber of above-mentioned the 2nd side, be characterised in that, the ratio D1/D2 of the diameter D1 of above-mentioned the 1st fuse and the diameter D2 of above-mentioned the 2nd fuse is 0.4 to 0.7, the nonlinear factor at wavelength 1550nm place is more than the 20/W/Km, the chromatic dispersion at wavelength 1550nm place is-1ps/nm/km to 1ps/nm/km, and above-mentioned the 1st fuse satisfies following relationship to the specific refractivity difference Δ 1 of above-mentioned covering and above-mentioned the 2nd fuse to the specific refractivity difference Δ 2 of covering.
(Δ2)＜-0.52·(Δ1)+1
Polarized wave according to such formation keeps optical fiber, just can reduce the absolute value that polarized wave keeps CHROMATIC DISPERSION IN FIBER OPTICS, and can make easily that can to make cutoff wavelength be the optical fiber that the following light signal non-linear outstanding, that be suitable for utilizing nonlinear optical phenomena of 1400nm is handled.
Have, among the embodiment of the optical fiber of above-mentioned the 2nd side, be characterised in that, above-mentioned the 2nd fuse is below-0.8% to the specific refractivity difference Δ 2 of above-mentioned covering, and above-mentioned the 1st fuse is more than 3.5% to the specific refractivity difference Δ 3 of above-mentioned the 2nd fuse.
Keep optical fiber according to the polarized wave of such formation, just can provide polarized wave to keep the CHROMATIC DISPERSION IN FIBER OPTICS slope little, and can to make cutoff wavelength be the optical fiber of following non-linear outstanding, the light signal processing that is suitable for utilizing nonlinear optical phenomena of 1400nm.
Among the embodiment of the optical fiber of above-mentioned the 2nd side, be characterised in that, it is the quartz glasss that added boron that above-mentioned stress is paid parts, and above-mentioned covering is the quartz glass that has added fluorine, above-mentioned stress pay parts to the specific refractivity difference Δ 4 of above-mentioned covering for below-0.1% or more than 0.1%.
Keep optical fiber according to the polarized wave of such formation, as connecting optical fiber each other the time, stress is paid position component and is confirmed just to become easily, connects just to become easy.
Optical wavelength changer of the present invention is characterised in that and has used above-mentioned optical fiber.
According to the optical wavelength changer of such formation, just can provide wavelength conversion outstanding optical wavelength changer.
As mentioned above, keep optical fiber, just can make the little value of polarized wave cross-talk, and can easily make the polarized wave maintenance optical fiber that non-linear light signal outstanding, that be suitable for utilizing nonlinear optical phenomena is handled for wishing according to polarized wave of the present invention.Also have, the optical wavelength changer of optical wavelength conversion good drawing property can be provided.
The optical fiber of the 3rd side of the present invention in the optical fiber that is made of fuse and covering, is characterised in that, nonlinear constant n 2/ Aeff is 20 * 10 -10More than/the W, the absolute value of the wavelength dispersion at wavelength 1550nm place is below the 20ps/nm/km, and the bending loss of the diameter 5mm at wavelength 1550nm place is below the 0.1dB/m, and the external diameter of above-mentioned covering is 70～110 μ m.
In the optical fiber of the present invention of above-mentioned formation, nonlinear constant n 2/ Aeff is 20 * 10 -10More than/the W, thereby can obtain high non-linearly, can carry out the light signal of the good non-linear phenomena of utilization ratio and handle.Preferably, nonlinear constant n 2/ Aeff is 40 * 10 -10More than/the W.
Also have, the absolute value of the wavelength dispersion at 1550nm place is below the 20ps/nm/km, thereby can be applicable to wavelength conversion and the wave shapings such as light 2R, light 3R that utilize non-linear phenomena.Preferably, the absolute value of the wavelength dispersion at 1550nm place can be for below the 2ps/nm/km.
Have, the bending loss of the diameter 5mm at wavelength 1550nm place is below the 0.1dB/m again, thereby can compactly curl.Preferably, bending loss can be for below the 0.05dB/m.
And the covering external diameter is 70～110 μ m, thereby can realize the low transmission loss.
The covering external diameter surpasses 110 μ m, and it is big that loss will become; And be lower than 70 μ m, and the intensity of optical fiber will descend, and reliability will reduce, and loss becomes greatly once more, is not preferred.
In addition, the optical fiber of covering external diameter 125 μ m is extensive use of, and but, is being positioned at the 1st fuse middle and high concentration ground doped germanium of fiber optic hub portion, and making nonlinear constant is 20 * 10 -10More than/the W, and to make the absolute value of the wavelength dispersion at 1550nm place be 20ps/nm/km when following, is in the optical fiber of 125 μ m at the covering external diameter, and loss will uprise.By contrast, for example the covering external diameter is reduced to the degree of 90 μ m, just can reduces loss under the situation of the size of not damaging nonlinear constant, this point is understood.The present invention makes according to this opinion just.
Like this, in the 1st fuse middle and high concentration doped germanium, and to make the absolute value of the wavelength dispersion at 1550nm place be below the 20ps/nm/km, makes the covering footpath be reduced to 90 μ m from 125 μ m, loss is descended, this mechanism is understood not too the chances are owing to produced following phenomenon.
That is, get over doped germanium in the silica glass, refractive index uprises more, and the softening temperature of silica glass descends.Therefore, high concentration ground doped germanium has significantly increased the highly nonlinear optical fiber of the refractive index of the 1st fuse, compares with the situation of optical fiber with common transmission line, and it is much lower that the softening temperature of the 1st fuse compares the softening temperature of the covering that is made of pure silicon stone glass.
, optical fiber is the bigbore base glass material that has the cross section index distribution structure identical with purpose optical fiber by synthetic, and it is carried out heating and melting, wire drawing, and its external diameter that pulls into regulation is made.In the operation of this wire drawing, the undergauge that softening through base glass material before this then is the base glass material external diameter till the optical fiber footpath then is each operation to optical fiber hardening by cooling directly again.
Can think, during the soften glass mother metal, for obtaining to make the high-temperature of the softening degree of covering, high concentration ground doped germanium and the 1st fuse that reduced softening temperature will stand necessary above high temperature, because the tension force when this high temperature and wire drawing, will produce defective in the fuse, increase loss thus.By contrast, can think, by reducing the covering external diameter, the thick attenuation of covering, the 1st fuse just can cool off as soon as possible, and the time that the 1st fuse stands high temperature shortens, thereby defective will reduce, and loss will reduce.
Also have, consider the hardening by cooling operation, just before having reduced the 1st fuse of softening temperature, harden then fuse sclerosis by the covering elder generation that the high silica glass of softening temperature constitutes in high concentration ground doped germanium.Therefore can infer, produce big distortion between the two at fuse and covering, it just becomes the reason that loss increases.
Can think that in particular for obtaining high non-linearity, when the 1st fuse middle and high concentration had mixed germanium, because this effect, it is big that loss will become., can think herein, reduce the external diameter of covering, the thickness attenuation of covering, with respect to covering, relatively hurry up, the mistiming of the 1st fuse and covering sclerosis diminished when the cooling raio covering of the 1st fuse footpath was big.Also have, can think, owing to reduced the volume of covering, the cumulative volume of the covering during cooling changes and will diminish.Therefore, can think that the deflection between the 1st fuse and covering will reduce, loss will reduce.
In addition, improve the refractive index of the 1st fuse, and the absolute value that makes the wavelength dispersion at wavelength 1550nm place is below the 20ps/nm/km, the bending loss that makes the diameter 5mm at wavelength 1550nm place again is the following optical fiber of the present invention of 0.1dB/m, with the refractive index that improves the 1st fuse, and the absolute value of the wavelength dispersion at wavelength 1550nm place is compared to negative the increase to-dispersion compensating fiber (DCF) below the 60ps/nm/km, had distribution of light intensity and concentrate on this feature in the 1st fuse.Therefore can think, as the highly nonlinear optical fiber of object of the present invention, compare with dispersion compensating fiber that the influence of the defective that produces in the 1st fuse of the germanium that mixed etc. increases, to improve loss be extremely important by reducing it.
Optical fiber involved in the present invention is by having the effect that improves refractive index, the adulterant high concentration ground that also has the effect that reduces softening temperature simultaneously is entrained in the 1st fuse and the silica class glass that obtains formation, thereby it is big to make nonlinear constant, and the absolute value of the wavelength dispersion at 1550nm place is the following optical fiber of 20ps/nm/km.As this adulterant, particularly preferably be germanium.
Also have, among the embodiment of the optical fiber of above-mentioned the 3rd side, preferably, cutoff wavelength is below the 1350nm.Cutoff wavelength is below the 1350nm, just can be used for comprising the wide band of S-band, C-band.
Have, among the embodiment of the optical fiber of above-mentioned the 3rd side, preferably, the wavelength dispersion slope at wavelength 1550nm place is 0.019ps/nm again 2Below/the km.The wavelength dispersion slope is 0.019ps/nm 2Below/the km, just can be provided at the little optical fiber of variation of the value of wavelength 1550nm band place's wavelength dispersion, just can utilize the light signal of good non-linear phenomena to handle at wide band.
The amplitude of fluctuation than the wavelength dispersion of length direction of the optical fiber at wavelength 1550nm place, preferably 1 optical fiber use in the long total length to 3ps/nm/km below.The amplitude of fluctuation than the wavelength dispersion of length direction of optical fiber is below the 3ps/nm/km, just can utilize the light signal of non-linear phenomena to handle well.
Also have, for equilibrium realizes obtaining high nonlinear constant and makes covering directly be in particular range and reduce the wastage, when fuse had the 1st fuse that is positioned at its central part, preferably the 1st fuse was more than 1.5% to the specific refractivity difference of covering.More preferably the 1st fuse is more than 2.5% to the specific refractivity difference of covering.
Like this, the 1st fuse is more than 2.5% to the specific refractivity difference of covering, just can obtain the cutoff wavelength, 20 * 10 of the following weak point of 1350nm simultaneously -10High nonlinear constant and 0.019ps/nm that/W is above 2The wavelength dispersion slope that/km is following, thereby be particularly preferred.
Particularly, fuse is made of the 1st fuse that is positioned at its central part and the 2nd fuse on every side thereof, covering is pure silicon stone or has silica class glass near the refractive index of pure silicon stone, the 2nd fuse is-1.2～-0.4% to the specific refractivity difference of covering, just can obtain the big and little optical fiber of chromatic dispersion gradient of nonlinear constant.
In this case, preferably the 1st fuse is more than 3% to the specific refractivity difference of the 2nd fuse.
Also have, the external diameter of the 2nd fuse is D2, and when the 1st fuse external diameter was D1, making D1/D2=Da was 0.3～0.7, just can obtain the optical fiber of the littler high non-linearity of chromatic dispersion gradient.
Among the embodiment of the optical fiber of above-mentioned the 3rd side, also can make single-mode fiber or dispersion-shifted fiber, and this weld portion is implemented the optical fiber that heat treated forms at the one or both ends of highly nonlinear optical fiber welding external diameter 120～130 μ m.
The covering external diameter is the words of 70～110 μ m, connect just very difficult at the scene with other optical fiber, and it is big that junction loss becomes, and in the highly nonlinear optical fiber involved in the present invention, make in advance the single-mode fiber of external diameter 120～130 μ m or dispersion-shifted fiber aim at separately the center and welding, weld portion is carried out heat treated, and welding connects dispersion-shifted fiber, so just can make the optical fiber that connects at the scene with other optical fiber easily.
Preferably, the optical fiber align center separately that makes highly nonlinear optical fiber involved in the present invention and want external diameter 120～130 μ m of welding.The center of aiming at separately just can reduce junction loss.Also have, preferably after the welding weld portion is carried out heat treated.Carry out heat treated after the welding, the adulterant of the fuse of connecting portion will spread, and the mode field footpath will enlarge, and so just can reduce the junction loss of weld portion.
Also have, in the optical fiber involved in the present invention,, thereby can reduce to comprise and to be rolled into web-like compactly by resin-coated external diameter because covering directly is 70～110 μ m.Optical fiber involved in the present invention is rolled into below the maximum coil diameter 20cm, preferably below the 18cm, the subsystem assembly that for example light 2R uses, light 3R uses, wavelength conversion is used that it is housed can utilize the light signal of high non-linearity phenomenon to handle, and also has compact advantage simultaneously.
Make the light signal processing device of the optical fiber that uses the 3rd side of the present invention.
The optical fiber of the 4th side of the present invention is characterised in that, n 2/ Aeff is a nonlinear constant, and a is a loss, and λ is a wavelength, when L is the length of optical fiber, λ in the scope of 1500nm～1600nm, the ((n of 2 π/λ) 2The value of/Aeff) [1-exp (aL)]/a satisfies more than the 1/W, and the absolute value of the wavelength dispersion at wavelength 1550nm place is below the 30ps/nm/km, and the bending loss of the diameter 5mm at wavelength 1550nm place is below the 0.5dB/m.
In the optical fiber of the present invention, there is the absolute value of the wavelength dispersion at wavelength 1550nm place to be necessary for below the 30ps/nm/km.This is that the absolute value of wavelength dispersion surpasses 30ps/nm/km, just can not carry out effective light signal and handle owing to carry out when the signal Processing of wavelength 1550nm band.
Also have, the bending loss of the diameter 5mm at wavelength 1550nm place is necessary for below the 0.5dB/m.This is because bending loss surpasses 0.5dB/m, get up to pack into roll of optical fiber in the optical signal device after, it is big that loss will become.It is big that loss becomes, and just as aftermentioned, the effective length of optical fiber shortens, and can not carry out effective light signal and handle.
N is arranged again 2/ Aeff is a nonlinear constant, and a is a loss, and λ is a wavelength, when L is the length of optical fiber, wavelength X in the scope of 1500nm～1600nm, the ((n of 2 π/λ) 2The value of/Aeff) [1-exp (aL)]/a must satisfy more than the 1/W.This is because the ((n of 2 π/λ) 2The value of/Aeff) [1-exp (aL)]/a just can not be carried out effective light signal and handle less than 1/W.
The nonlinear phase that causes from phase modulation (PM) of non-linear phenomena is offset Φ NL, is represented by following formula (1).
ΦNL＝(2π/λ)(n 2/Aeff)ILeff????????????????????????????(1)
Herein, λ represents wavelength, n 2/ Aeff represents nonlinear constant, and I represents light intensity, and Leff represents effective length, n 2The expression nonlinear refractive index, Aeff represents net sectional area.And effective length Leff is represented by following formula (2).
Leff＝[1-exp(-aL)]/a????????????????????????????????????(2)
Herein, a represents loss, and L represents the length of optical fiber.
According to formula (1) and formula (2), the nonlinear phase skew is represented by following formula (3).
ΦNL＝(2π/λ)(n 2/Aeff)I[1-exp(-aL)]/a?????????????????(3)
According to above-mentioned formula (3), the length of calculating optical fiber is 2km, the λ Φ NL/I when being 1550nm, just as Figure 16 represents.
As can be seen, for the long 2km of optical fiber, wavelength dispersion-1ps/nm/km, loss 0.37dB/km, nonlinear constant n 2/ Aeff20 * 10 -10Optical fiber, the non-linear of using as wave shaping of signal Processing is sufficient.Calculate the ((n of 2 π/λ) of this moment 2/ Aeff) [1-exp (aL)]/a, be the degree of 14.9/W.
Also have, as can be seen, for the long 0.1km of optical fiber, wavelength dispersion 0ps/nm/km, loss 0.48dB/km, nonlinear constant n 2/ Aeff30 * 10 -10Optical fiber, the non-linear of using as wavelength conversion of signal Processing is sufficient.Calculate the ((n of 2 π/λ) of this moment 2/ Aeff) [1-exp (aL)]/a, be 1.09/W.
That is the ((n of 2 π/λ), 2The value of/Aeff) [1-exp (aL)]/a is necessary for more than the 1/W.
Its refractive index is improved, thereby obtain the high optical fiber of nonlinear constant in fuse middle and high concentration ground doped germanium, the loss of optical fiber will uprise significantly, and this is the problem that produces.Get over doped germanium, the loss of optical fiber increases more.
Loss uprises, and from formula (3) or Fig. 1 as can be known, though the nonlinear constant height, because loss, the nonlinear phase skew diminishes, and just can not utilize the effective light signal processing of non-linear phenomena.Therefore, must select nonlinear constant n 2The long L of/Aeff, loss a and optical fiber makes the ((n of 2 π/λ) 2/ Aeff) [1-exp (aL)]/a is more than the 1/W.
Also have, in the optical fiber of above-mentioned the 4th side, preferably, λ is in the scope of 1500nm～1600nm, and (2 π/λ) (n2/Aefff) are 8～17/W/km, and L is 0.5～30km, and loss a is 0.2～0.6dB/km.
((the n of 2 π/λ) 2/ Aeff) be the value that is called nonlinear factor γ, this value is big more, and from above-mentioned formula (1) as can be known, the nonlinear phase skew is just big more, can cause non-linear phenomena effectively more.
((the n of 2 π/λ) 2/ Aeff) less than 8/W/km, just be difficult to obtain sufficient non-linear phenomena.On the other hand, the ((n of 2 π/λ) 2/ Aeff) surpass the words of 17/W/km, just must be in fuse middle and high concentration ground doped germanium, thereby loss a will become big, during the scope of the long L of optical fiber more than 0.5km, effective length Leff depends on loss a, the tendency that diminishes is remarkable, thereby the actual long L of optical fiber is long, just is difficult to obtain big nonlinear phase skew.
In optical fiber length less than 0.5km, the ((n of 2 π/λ) 2/ Aeff) be the following scope of 17/W/km, can not obtain sufficient non-linear phenomena.Also have, the long L of optical fiber surpasses 30km, and effective length Leff depends on loss a, and the tendency that diminishes is remarkable, and therefore, the actual long L of optical fiber is long, just is difficult to obtain big nonlinear phase skew.
For the ((n of 2 π/λ) 2/ Aeff) be the above optical fiber of 8/W/km, must be in fuse with high concentration ground doped germanium to a certain degree, thereby be difficult to make the optical fiber of loss a less than 0.2dB/km.Also have, loss a surpasses 0.6dB/km, and effective length Leff will diminish, thereby can not obtain sufficient non-linear phenomena.
Have again, among the embodiment of the optical fiber of above-mentioned the 4th side, preferably, λ in 1500nm～1600nm scope, the ((n of 2 π/λ) 2/ Aeff) be 17～27/W/km, L is 0.01～10km, loss a is 0.4～2dB/km.
((the n of 2 π/λ) 2/ during Aeff) less than 17/W/km, be below the 10km at the long L of optical fiber, loss is the above scope of 0.4dB/km, just is difficult to obtain sufficient non-linear phenomena.Make the ((n of 2 π/λ) 2/ Aeff) surpass 27/W/km, just must be in fuse again high concentration doped germanium, the ((n of 2 π/λ) 2/ Aeff) surpass 27/W/km more, just difficult more in fuse middle and high concentration ground doped germanium, and, promptly enable to obtain the fuse of high-concentration dopant germanium, its softening temperature is compared with the silica of covering, also can extremely reduce, thereby just produce distortion easily when making, break the easy variation of manufacturing easily.
Optical fiber length just can not obtain sufficient non-linear phenomena during less than 0.01km.Also have, the long L of optical fiber surpasses 10km, and during the scope of loss a more than 0.4dB/km, effective length Leff depends on loss a, and the tendency that diminishes is remarkable, thereby the actual long L of optical fiber is long, just is difficult to obtain big nonlinear phase and is offset.
For the ((n of 2 π/λ) 2/ Aeff) be the above optical fiber of 17/W/km, must be in fuse middle and high concentration ground doped germanium, thereby be difficult to make the optical fiber of loss a less than 0.4dB/km.Also have, loss a surpasses 2dB/km, even if the ((n of 2 π/λ) 2/ Aeff) arrive 17/W/km greatly, but the tendency that effective length Leff diminishes is remarkable, thereby be difficult to obtain sufficient non-linear phenomena.
As mentioned above, according to the present invention, can obtain to utilize effectively the optical fiber of the signal Processing of non-linear phenomena.In addition, optical fiber of the present invention is rolled into the use of packing into below the maximum diameter 16cm, just can obtains compact effectively light signal processing device.
Description of drawings
Fig. 1 represents an embodiment of optical fiber of the present invention, and Fig. 1 (a) represents index distribution, and Fig. 1 (b) is the cross-sectional view of the part of expression xsect.
Fig. 2 is the curve of the analog result of the D1/D2 of the optical fiber in the presentation graphs 1 and chromatic dispersion gradient.
Fig. 3 is the curve of the relation of the α that provides of expression simulation and chromatic dispersion gradient.
Fig. 4 is the curve of the relation of the α that provides of expression simulation and net sectional area Aeff.
Fig. 5 is the synoptic diagram that expression is used for optical fiber of the present invention one embodiment A of wavelength shifter.
Fig. 6 is the synoptic diagram that expression is used for optical fiber of the present invention one embodiment A of pulse shortener.
Fig. 7 is the synoptic diagram of an embodiment that the light signal processing device of optical fiber of the present invention has been adopted in expression.
Fig. 8 is the schematic cross-section that polarized wave of the present invention keeps optical fiber.
Fig. 9 is the figure of an example of the index distribution that keeps optical fiber of the polarized wave in the presentation graphs 8.
Figure 10 is the curve of the relation of the cutoff wavelength λ c that provides of expression simulation and specific refractivity difference Δ 1, specific refractivity difference Δ 2.
Figure 11 is the curve of the relation of the ratio D1/D2=Da of the 1st fuse footpath D1 that provides of expression simulation and the 2nd fuse footpath D2 and chromatic dispersion gradient.
Figure 12 is the curve of the relation of the ratio D1/D2=Da of the 1st fuse footpath D1 that provides of expression simulation and the 2nd fuse footpath D2 and net sectional area Aeff.
Figure 13 is the curve of the relation of the ratio D1/D2=Da of the 1st fuse footpath D1 that provides of expression simulation and the 2nd fuse footpath D2 and cutoff wavelength λ c.
Figure 14 is that the welding of low loss fiber of the present invention and other optical fiber is in conjunction with the optical fiber structural map.
Figure 15 is the enlarged drawing of the welding joint portion of Figure 14.
Figure 16 is the dependent performance plot of loss a of expression Φ NL/I.
Figure 17 is the Φ NL/I of expression in the various optical fiber and the performance plot of the long relation of optical fiber.
Figure 18 is the Φ NL/I of expression in the various optical fiber and the performance plot of the long relation of optical fiber.
Figure 19 is the skeleton diagram that expression studies the refractive index profile shape of routine D1, D2, D4～D6.
Figure 20 is the skeleton diagram that expression studies the cross-sectional configuration of routine D1, D2, D4～D6.
Figure 21 is the skeleton diagram that expression studies the refractive index profile shape of routine D3.
Figure 22 is the skeleton diagram that expression studies the cross-sectional configuration of routine D3.
Embodiment
A: have low dispersion values change and hang down the highly nonlinear optical fiber of the type of dispersion values
Fig. 1～Fig. 7 describes optical fiber of the present invention in detail and has adopted the optical wavelength changer of this optical fiber and the embodiment of pulse shortener.
Optical fiber involved in the present invention is the optical fiber that near the input light the wavelength 1550nm is produced non-linear phenomena, and one of its feature is that the chromatic dispersion gradient at wavelength 1550nm place is-0.01～0.01ps/nm 2/ km.
As mentioned above, chromatic dispersion gradient is-0.01～0.01ps/nm 2/ km like this, just can be provided in the wide wavelength region may that comprises wavelength 1550nm, the little and little optical fiber of absolute value chromatic dispersion of the change of dispersion values.
Also have, chromatic dispersion gradient is-0.01～0.01ps/nm in wide wavelength region may 2/ km, dispersion values just can significantly not change in comprising the wide wavelength region may of 1550nm.Therefore, just can utilize the good light signal of nonlinear optical phenomena to handle to the wide wavelength region may that comprises wavelength 1550nm.
, the absolute value of chromatic dispersion gradient is 0.01ps/nm 2/ km is above, and to wavelength 1550nm different wave length nearby, it is big that the change of dispersion values will become relatively.Therefore, chromatic dispersion gradient is necessary for-0.01～0.01ps/nm 2/ km.And, for to comprising that the wide wavelength region may of wavelength 1550nm further reduces the change of dispersion values, preferably-0.005～0.005ps/nm 2/ km.
Also have, the absolute value of dispersion values is below the 10ps/nm/km, and the nonlinear constant at wavelength 1550nm place is 30 * 10 -10Also one of feature of optical fiber of the present invention more than/the W.
Nonlinear constant is 30 * 10 -10More than/the W, as described below, just can obtain high nonlinear optical fiber.
Also have, for single-mode fiber, cutoff wavelength λ c must be according to using wavelength to reduce.Therefore, preferably, cutoff wavelength λ c is below the 1450nm.Cutoff wavelength λ c is below the 1450nm, just can be used in the wide wavelength band territory that comprises S-band, C-band and L-band.
Herein, cutoff wavelength λ c is meant the fiber cut off wavelength λ c that G.650 ITU-T (international electrical communication Colaesce) defines.In addition, definition and the measuring method of ITU-TG.650 deferred in the term that defines especially in this instructions.
In addition, preferably, above-mentioned net sectional area Aeff is 12 μ m 2Below.Making net sectional area Aeff is 12 μ m 2Below, just can obtain high nonlinear constant.
Nonlinear constant will increase nonlinear constant shown in above-mentioned (1) formula, just must increase the nonlinear refractive index n of optical fiber 2, or reduce net sectional area Aeff as far as possible, and reality feasible be to reduce net sectional area as far as possible, this point is as mentioned above.
Therefore, obtain nonlinear big optical fiber, as the structure of optical fiber, net sectional area Aeff must be little.Also have, the absolute value of the chromatic dispersion at use wavelength place also must be little.Therefore, preferably, the absolute value of the dispersion values at wavelength 1550nm place is below the 10ps/nm/km, more preferably below the 5ps/nm/km.
Making net sectional area Aeff is 12 μ m 2Below, just can obtain high nonlinear constant.More preferably, making effect sectional area Aeff is 10 μ m 2Below, can obtain higher nonlinear constant, the result, the nonlinear constant that just can obtain wavelength 1550nm place is 40 * 10 -10The optical fiber of the value that/W is above.
Also have, the amplitude of fluctuation of the dispersion values of this description as mentioned above, for the optical fiber total length of practical length, can be measured by the chromatic dispersion distribution measurement instrument that utilizes the mode that for example Mollenauer worked out.
Preferably, the optical fiber of the random wave strong point among wavelength 1510～1590nm is 0.001～1ps/nm/km than the change of the chromatic dispersion of length direction in the long total length of the use of 1 optical fiber.
Optical fiber is than the amplitude of fluctuation of the dispersion values of length direction, 1 optical fiber use in the long total length to 1ps/nm/km below, just can utilize the good light signal processing of non-linear phenomena.More preferably, the optical fiber of the random wave strong point among wavelength 1510～1590nm than the change of the dispersion values of length direction 1 optical fiber use in the long total length to 0.2ps/nm/km below.Be below the 0.2ps/nm/km like this, just can utilize the better light signal of non-linear phenomena to handle.
, in fact, will make being of uniform thickness of fuse and covering in the fibre parent material stage in order to suppress the change of optical fiber than the dispersion values of length direction.Particularly, for example at the carbon black synthesis phase that adopts OVD method or VAD method, just must manage, the raw material of accumulation is become evenly, when this optical fibre parent material stretch was become the external diameter of hope, the difference that requires the external diameter change was that the high precision below 0.2% stretches.
Fig. 1 represents a typical example of the optical fiber of non-linear dispersion-shifted type involved in the present invention.Fig. 1 (a) represents the index distribution of this optical fiber, and Fig. 1 (b) represents the part of its xsect, i.e. the 1st fuse 1 and be located at the 2nd fuse 2 in the outside of the 1st fuse 1 has omitted the line in the outside of the covering 4 of the arranged outside of the 2nd fuse 2.
Shown in Fig. 1 (a), this optical fiber has the refractive index higher than pure silicon stone, comprise the index distribution of α time shown in (2) that have following formula the 1st fuse 1, be located at the outside of the 1st fuse 1 and have the 2nd fuse 2 of the refractive index lower than pure silicon stone and be located at the outer diameter D 1 of covering 4, the 1 fuses 1 in the outside of the 2nd fuse 2 and the ratio D1/D2 of the outer diameter D 2 of the 2nd fuse 2 is more than 0.3,0.8 with.
In this manual, define the α of the shape of expression index distribution by following formula (2) herein.
n 2(r)＝n c1 2{1-2·Δ1·(2r/D1) α}????????????????????????(2)
Herein, 0≤r≤D1/2.
Herein, r represents the position of fiber radius direction, and n (r) is illustrated in the refractive index of position r.Also has n C1It is the largest refractive index of the 1st fuse 1.
Also have, the diameter D1 of above-mentioned the 1st fuse 1 be the length of line of the position of the refractive index that connection equates with covering 4 in the 1st fuse 1.Also have, the diameter D2 of the 2nd fuse 2 is the length of line of position that is connected 1/2 refractive index of Δ 2 in the borderline region of the 2nd fuse 2 and covering 4.
Also have, the specific refractivity difference Δ 2 of 2 pairs of coverings 4 of refractive indices the 1, the 2nd fuse of 1 pair of above-mentioned covering 4 of the 1st fuse is by following formula (3) and (4) expression.
Δ1＝{(n c1-n c)/n c1}·100????????????????????????(3)
Δ2＝{(n c2-n c)/n c2}·100????????????????????????(4)
Herein, above-mentioned various in, n C1Be the largest refractive index of the 1st fuse 1, n C2Be the minimum refractive index of the 2nd fuse 2, n cRefractive index for covering 4.
In the structure of optical fiber shown in Figure 1, the ratio D1/D2 of the outer diameter D 1 by adjusting above-mentioned the 1st fuse 1 and the outer diameter D 2 of the 2nd fuse 2 just can reduce the value of chromatic dispersion gradient.
To this, the variation of value of the caused chromatic dispersion gradient of ratio D1/D2 of the outer diameter D 2 of the outer diameter D 1 of adjusting above-mentioned the 1st fuse 1 and the 2nd fuse 2 is described with the constructing analog example of this optical fiber.
The relation of the value of the chromatic dispersion gradient when Fig. 2 represents that the D1/D2 at wavelength 1550nm place and chromatic dispersion are 0ps/nm/km.Also has the index distribution of 2 kinds of optical fiber 1,2 that table 1 expression is used herein.
Table 1
??Δ1 ??Δ2 ??α
Optical fiber 1 ??2.8％ ??-1％ ??8
Optical fiber 2 ??2.3％ ??-1％ ??7
As shown in Figure 2, D1/D2 is less than 0.3 o'clock, or D1/D2 surpasses at 0.8 o'clock, and chromatic dispersion gradient just becomes and has ratio-0.01～0.01ps/nm 2The chromatic dispersion gradient that/km is big.
Also have, as shown in Figure 2, further dwindle the scope of D1/D2, making this value is more than 0.4 below 0.7, just the value of chromatic dispersion gradient is in-0.005～0.005ps/nm 2The scope of/km.Therefore, preferably, the ratio D1/D2 that makes the outer diameter D 2 of the outer diameter D 1 of the 1st fuse and the 2nd fuse is more than 0.4 below 0.7.
Generally speaking, little net sectional area Aeff can obtain by the specific refractivity difference of increase fuse to covering.But it is poor to the specific refractivity of covering only to increase fuse, and cutoff wavelength λ c will move to long wavelength side, will become difficult at guaranteeing of transmitting of the single mode of wide band.By contrast, get structure for example shown in Figure 1, just can take into account little net sectional area Aeff and low cutoff wavelength λ c.
Also have, the specific refractivity difference Δ 1 of 1 pair of covering 4 of the 1st fuse is the 2.0～5.0%, the 2nd fuse 2 and pure silicon stone preferably, and promptly the specific refractivity difference Δ 2 of the covering 4 in this example preferably-1.4～-0.7%.
The specific refractivity difference Δ 1 of 1 pair of covering 4 of the 1st fuse is less than 2.0%, and net sectional area Aeff will become greatly, and the non-linear of optical fiber diminishes relatively.Also have, specific refractivity difference Δ 1 uprises, and cutoff wavelength λ c just moves to long wavelength side.Therefore, specific refractivity difference Δ 1 surpasses 5.0%, must too much consider optical fiber as the cutoff wavelength λ c that single mode relied on, and the result, the productivity of optical fiber will variation.
In other words, specific refractivity difference Δ 1 surpasses 5.0%, optical fiber as the control of the cutoff wavelength λ c that single mode the relied on difficulty that just becomes, the result, creating conditions of optical fiber becomes tight, the productivity variation.
Also have, it is big that the value of the chromatic dispersion gradient at 1550nm place becomes, and when carrying out the light signal processing, to wavelength 1550nm different wave length nearby, the change of dispersion values will become greatly, and this is the problem that exists.
Also have, the specific refractivity difference Δ 2 of 2 pairs of coverings 4 of the 2nd fuse increases to minus side, just can reduce the absolute value of the dispersion values at wavelength 1550nm place, and reduce chromatic dispersion gradient.
, increase specific refractivity difference Δ 2 to minus side, cutoff wavelength λ c just moves to short wavelength side.To this, if specific refractivity difference Δ 1 is made as 2.0～5.0%, and specific refractivity difference Δ 2 is made as-1.4%～-0.7%, and just can make chromatic dispersion gradient is-0.01～0.01ps/nm 2The value of/km.Can also make cutoff wavelength λ c also for below the 1450nm.
On the other hand, specific refractivity difference Δ 2 is lower than-1.4%, for example just must a large amount of doped with fluorine in the 2nd fuse 2, and the manufacturing of the optical fiber difficulty that will become, productivity variation.
In addition, specific refractivity difference Δ 1 more preferably 2.4～4.0%, Δ 2 is more preferably-1.2～-0.8%.If in this scope, just can make high non-linear and low chromatic dispersion gradient and the optical fiber of cutoff wavelength λ c below 1450nm with high productivity more, the stability of performance also can further improve.
Have, the refractive index profile shape that makes the 1st fuse 1 is α time a index distribution, by increasing this α, just can reduce chromatic dispersion gradient, can also reduce net sectional area Aeff more again.Therefore, preferably, the refractive index profile shape of the 1st fuse 1 is α time a index distribution, and α is more than 3.More preferably α is more than 6.
Herein, having increased α is favourable for reducing chromatic dispersion gradient, with Fig. 3 and Fig. 4 of representing the simulation example that one of optical fiber of the present invention is routine this point is described.
Fig. 3 represents the relation of α and chromatic dispersion gradient, and Fig. 4 represents the relation of α and net sectional area Aeff.Also has each structure of 2 kinds of optical fiber A, B that table 2 expression is used herein.
Table 2
??Δ1 ??Δ2 ??Δ1/Δ2
Optical fiber A ??2.60％ ??-0.80％ ??0.5
Optical fiber B ??3％ ??-1％ ??0.4
As shown in Figure 3, increase the value of α, just can reduce chromatic dispersion gradient.As can be seen, particularly α is become 3 from 2, just can make the value of chromatic dispersion gradient in optical fiber A, reduce about 0.009ps/nm 2/ km, and in optical fiber B, reduce about 0.01ps/nm 2/ km.It is very effective for the reduction of chromatic dispersion gradient to increase α like this.
Also have, as shown in Figure 4, the value that increases α just can reduce net sectional area Aeff.Particularly α is become 3 from 2, just can reduce net sectional area Aeff about 8% among both at optical fiber A, optical fiber B.
Herein, as a kind of method of the α that is used to increase the 1st fuse 1, have and adopt VAD method or MCVD method the fuse mother metal with refractive index higher than pure silicon stone to be made in advance the method for the big fuse mother metal of its refractive index profile shape α.Can also adopt etching method or the outer mills of machinery such as HF to the surface of the fuse mother metal made of this method, further increase the value of the α of refractive index profile shape.
If particularly adopt above-mentioned method,, α also is relatively easy to more than 3 from manufacture view.
Also have, as shown in Figure 3, increase the value of α again, be more than 6, just can reduce chromatic dispersion gradient again, as shown in Figure 4, can also reduce net sectional area Aeff.
By the way, be zone more than 6 at α, shown in Fig. 3,4, chromatic dispersion gradient continues greatly and bit by bit to diminish along with α becomes, and but, dwindling of net sectional area Aeff roughly is state of saturation.Therefore, preferably, making α at least is more than 6.
Embodiment
The value and the characteristic value thereof of the parameter of each optical fiber shown in table 3 expression embodiments of the invention A1～embodiment A 10.In addition, MFD is meant the mode field footpath in the table 3.
Table 3
??Δ1 ??Δ2 ??D1/D2 ??α Chromatic dispersion Slope ??MFD ??A eff ??λc ??n 2/A eff
??％ ??％ ??ps/nm/km ??ps/nm 2/km ??μm ??μm 2 ??nm ??/W
Measure wavelength ??1550nm ??1550nm ??1550nm ??1550nm ??1550nm
Embodiment A 1 ??3 ??-1 ??0.35 ??4 ??-3.96 ??0.0091 ??3.273 ??8.38 ??1183 ??69.2×10 -10
Embodiment A 2 ??3 ??-1 ??0.55 ??4 ??-3.71 ??-0.001 ??3.354 ??8.84 ??1255 ??65.5×10 -10
Embodiment A 3 ??5 ??-1.1 ??0.5 ??5 ??-4.94 ??0.0057 ??2.759 ??6.04 ??1448 ??115.9×10 -10
Embodiment A 4 ??4 ??-0.9 ??0.6 ??4.5 ??-9.1 ??-0.0061 ??3.011 ??7.15 ??1382 ??90.9×10 -10
Embodiment A 5 ??4 ??-0.9 ??0.6 ??7 ??-9.31 ??0.003 ??2.999 ??7.12 ??1385 ??91.3×10 -10
Embodiment A 6 ??2.6 ??-1 ??0.5 ??6 ??3.71 ??0.01 ??3.559 ??10.07 ??1261 ??49.7×10 -10
Embodiment A 7 ??2 ??-0.8 ??0.4 ??4 ??-2.99 ??0.0087 ??3.875 ??11.88 ??1052 ??33.7×10 -10
Embodiment A 8 ??2.9 ??-1 ??0.35 ??7.5 ??0.705 ??0.0086 ??3.386 ??9.17 ??1275 ??58.5×10 -10
Embodiment A 9 ??2.8 ??-1 ??0.45 ??7 ??0.24 ??0.0018 ??3.51 ??9.73 ??1283 ??50.6×10 -10
Embodiment A 10 ??2.8 ??-1 ??0.55 ??5 ??-3.48 ??-0.0034 ??3.209 ??10.1 ??1295 ??48.1×10 -10
Embodiment A 1～embodiment A 10 all is that the absolute value of the chromatic dispersion at wavelength 1550nm place is below the 10ps/nm/km, and chromatic dispersion gradient is-0.01～0.01ps/nm 2/ km.Also have, cutoff wavelength λ c is below the 1450nm, and net sectional area Aeff is 12 μ m 2Below.
Herein, be the result who obtains by simulation to the characteristic value of embodiment A 1～embodiment A 7 expression, embodiment A 8～A10 is an actual fabrication optical fiber, and it is estimated and the characteristic value that obtains.In addition, the characteristic value of the actual optical fiber that makes is roughly consistent with the result who obtains by simulation.
Head sees embodiment A 1 and embodiment A 2.For easy comparison, make the value of chromatic dispersion at wavelength 1550nm place roughly the same.
The optical fiber of embodiment A 1, the ratio D1/D2 of the outer diameter D 1 of the 1st fuse 1 and the outer diameter D 2 of the 2nd fuse 2 is 0.35, D1/D2 is 0.55 among the embodiment 2.
The characteristic value that obtains in two optical fiber is compared, and embodiment A 2 one sides are bigger than embodiment 1 net sectional area Aeff, and cutoff wavelength λ c is at long wavelength side, and but, the value of the chromatic dispersion gradient at wavelength 1550nm place is quite little value.That is,, can infer, be more than 0.3, compare below 0.8, preferably more than 0.4, below 0.7 with D1/D2 from the viewpoint of chromatic dispersion gradient.
Secondly, same as described above, embodiment A 4 and embodiment A 5 are compared.The refractive index profile shape of the 1st fuse is α curve in the embodiment A 4, and α is 4.5.On the other hand, α is 7 in the embodiment A 5.Characteristic value to the optical fiber that obtains respectively compares, and embodiment A 5 one sides present than the value that chromatic dispersion gradient reduce, net sectional area Aeff also little of embodiment A 4 at wavelength 1550nm place.Can infer according to this viewpoint, be to compare more than 3.0 with α, preferably more than 6.0.
Also have, measured the chromatic dispersion change than length direction of the optical fiber of embodiment A 8 and embodiment A 9 expressions.As a result, in the embodiment A 9, when measuring wavelength 1552nm, total length 3km has the chromatic dispersion change of 1.9ps/nm/km.It is scaled every 1km, is equivalent to the chromatic dispersion change of 0.75ps/nm/km.Also have, for the optical fiber of embodiment A 9 expressions, when measuring wavelength 1556nm, total length 15km has the chromatic dispersion change of 0.15ps/nm/km.Equally, it is scaled every 1km, is equivalent to the chromatic dispersion change of 0.08ps/nm/km.If present this optical fiber is used for light signal processing device, can use 10m～10km for per 1.For example, the use length of 1 optical fiber as 1km, the optical fiber of embodiment A 8, longer side change is that 0.75ps/nm/km, the optical fiber of embodiment A 9 are 0.08ps/nm/km in the long total length of using of 1 optical fiber, these change all in permissible range.
The value and the characteristic value thereof of the parameter of each optical fiber of table 4 expression Comparative examples A 1～Comparative examples A 5 expressions.
In addition, MFD also is meant the mode field footpath in table 4.
Table 4
??Δ1 ??Δ2 ??D1/D2 ??α Chromatic dispersion Slope ??MFD ??A eff ??λc ??n 2/A eff
??％ ??％ ??ps/nm/km ??ps/nm 2/km ??μm ??μm 2 ??nm ??/W
Measure wavelength ??1550nm ??1550nm ??1550nm ??1550nm ??1550nm
Comparative examples A 1 ??3 ??-0.8 ??0.25 ??4 ??-4 ??0.018 ??3.376 ??8.85 ??1215 ??65.5×10 -10
Comparative examples A 2 ??3.2 ??-0.5 ??0.5 ??4 ??-2.14 ??0.0199 ??3.466 ??9.37 ??1393 ??61.9×10 -10
Comparative examples A 3 ??1.8 ??-0.9 ??0.45 ??4 ??1.9 ??0.0085 ??4.037 ??12.68 ??1059 ??29.1×10 -10
Comparative examples A 4 ??3 ??-1 ??0.48 ??2.5 ??1.02 ??0.0258 ??3.519 ??9.6 ??1254 ??67.7×10 -10
Comparative examples A 5 ??5.5 ??-1 ??0.55 ??5 ??-2.33 ??0.0148 ??2.729 ??5.95 ??1585 ??109.2×10 -10
At first, in the optical fiber of Comparative examples A 1, the ratio of the ratio D1/D2 of the outer diameter D 1 of the 1st fuse 1 and the outer diameter D 2 of the 2nd fuse 2 is 0.25.The value of chromatic dispersion gradient becomes big relatively in this optical fiber, and when wide wavelength region may was used, it is big that the change of dispersion values becomes, and can not utilize the good light signal of non-linear phenomena to handle.
In the Comparative examples A 2, the specific refractivity difference Δ 2 of 2 pairs of coverings 4 of the 2nd fuse is-0.5%.It is big that the value of the CHROMATIC DISPERSION IN FIBER OPTICS slope that obtains becomes relatively, and this optical fiber is also identical with above-mentioned comparative example 1, and when wide wavelength region may was used, it is big that the change of dispersion values becomes, and can not utilize the better light signal of non-linear phenomena to handle.
In the optical fiber of Comparative examples A 3, the specific refractivity difference Δ 1 of 1 pair of covering 4 of the 1st fuse is 1.8%.Net sectional area Aeff becomes big relatively in the optical fiber that obtains, and nonlinear constant γ can not be 30 * 10 -10More than/the W.
Also have, in the optical fiber of Comparative examples A 4, the refractive index profile shape of the 1st fuse 1 is α curve, and the value of α is 2.5.It is big that the value of the CHROMATIC DISPERSION IN FIBER OPTICS slope that obtains becomes relatively, identical with comparative example 2 with above-mentioned comparative example 1, and when wide wavelength region may was used, it is big that the change of dispersion values becomes, and can not utilize the better light signal of non-linear phenomena to handle.
Have, in the Comparative examples A 5, the specific refractivity difference Δ 1 of the 1st fuse 1 and pure silicon stone is 5.5% again.Cutoff wavelength λ c has shifted to long wavelength side in this optical fiber, and problem is arranged when wavelength 1550nm uses.
Fig. 5 represents as one of the optical wavelength changer of one of light signal processing device that has adopted optical fiber of the present invention example example.According to this optical wavelength changer, can always be transformed to other wavelength to signal light wavelength one.
Herein, Fig. 5 is simply described.In addition, the dispersion values of elder generation's investigation optical fiber 7 of the present invention is zero wavelength in advance.
At first, this dispersion values is that zero wavelength exciting light (wavelength X s) nearby sends from light source 11, is coupled with flashlight 12 (wavelength X p).Then enter in the optical fiber 17 of the present invention.At this moment, in this optical fiber 17, produce and be called the big non-linear phenomena that four ripples mix, flashlight 12 is transformed to wavelength X in the following formula (5).Always carried out optical wavelength conversion with regard to one like this.
λ＝(λp-λs)+λp???????????????????????????(5)
By the way, the polarized wave controller of symbol 13 expression alignment polarized waves in Fig. 5, symbol 14 expression EDFA, it is the fiber amplifier (image intensifer) of er-doped, the coupling mechanism that symbol 15 expressions combine exciting light (wavelength X s) and flashlight 12 from light source, the symbol 16 expression polarizers.
Also have, Fig. 6 has represented to adopt one of the pulse shortener of optical fiber of the present invention example.In Fig. 6, symbol 21,22 is represented the light source that wavelength is different respectively, symbol 23 expression polarized wave controllers, symbol 24 expression coupling mechanisms.Also have the symbol 25 expression polarizers, symbol 26 expression EDFA.And the optical fiber that is connected respectively to the optical fiber of EDFA26 and symbol 28 expressions from above-mentioned light source 21,22 is general single-mode fiber, and symbol 27 is an optical fiber of the present invention.Length alternately connects optical fiber of the present invention 27 and general single-mode fiber 28 and constitutes pulse shortener like this, in accordance with regulations.
But, among Fig. 5 and Fig. 6,, only express optical wavelength changer and pulse shortener, but much less, in addition, for example waveform shaper etc. also can be used optical fiber of the present invention as the light signal processing device that has adopted optical fiber of the present invention.
So-called light signal processing device as shown in Figure 7, is made of light source 31, optical fiber of the present invention 32, signal processing part 33,34 at least, signal processing part be located at before and after the optical fiber of the present invention certain, or be located at two places.As light signal processing device, wavelength conversion machine and pulse shortener etc. are arranged.
B: the highly nonlinear optical fiber of polarized wave maintenance
Fig. 8～Figure 16 describes the optical fiber of polarized wave maintenance of the present invention in detail and has adopted this polarized wave to keep the embodiment of the optical wavelength changer of optical fiber.
Fig. 8 represents the schematic cross-section of an embodiment of the optical fiber of quartz glass system polarized wave maintenance of the present invention, and the polarized wave in Fig. 9 presentation graphs 8 keeps one of index distribution of optical fiber 810 example.As shown in Figure 8, polarized wave of the present invention keeps optical fiber 810 to be made of fuse 83 and the covering 84 that is located at its periphery, and this fuse 83 is made of with the 2nd fuse 82 that is located at its periphery the 1st fuse 81 that is positioned at central part.Also have, folder is provided with 2 stress in fuse 83 both sides and pays parts 85 every fuse 83.Omitted among Fig. 8, but, the resinous coat that is made of uv-hardening resin etc. has usually been arranged in the outside of this covering 84.
Herein, the specific refractivity difference Δ 1 of 81 pairs of above-mentioned coverings 84 of the 1st fuse is necessary for more than 1.8%.Its reason is, if Δ 1 less than 1.8%, just can not obtain sufficient non-linear phenomena.By the way, in order more positively to have lured non-linear phenomena, preferably making Δ 1 is more than 2.5%, more preferably more than 3.5%.To quartz glass,, just can improve the refractive index of the 1st fuse 81 so far by adding for example germanium.
Also have, this covering 84 has preferably added the quartz glass of fluorine.In covering 84, add fluorine, just increase the specific refractivity difference Δ 1 of 81 pairs of coverings 84 of the 1st fuse easily, just can obtain to have high nonlinear polarized wave and keep optical fiber.
Have again, its softening temperature is descended by in covering 84, adding fluorine.As a result, fibre parent material is carried out wire drawing, when obtaining polarized wave of the present invention and keeping optical fiber, just can reduce wire-drawing temperature, obtain the low polarized wave maintenance optical fiber of loss easily.
Also have, the 2nd fuse 82 has the refractive index lower than the 1st fuse 81, and has the refractive index lower than covering 84.Having again, the specific refractivity difference Δ 2 of 82 pairs of coverings 84 of the 2nd fuse is necessary for-below 0.1%.Preferably-below 0.8%.Its reason is, if surpass-0.1%, particularly, if-0.05%, cutoff wavelength just becomes the long wavelength, and chromatic dispersion gradient becomes big.
And the 2nd fuse 82 is also identical with above-mentioned covering 84, just can reduce its refractive index by add fluorine in quartz glass.
, increase the specific refractivity difference Δ 1 of 81 pairs of coverings 84 of the 1st fuse herein, nonlinear factor just can increase, but cutoff wavelength just becomes the long wavelength, and chromatic dispersion gradient also becomes big.Therefore, the non-refractive indices 1 that for example makes 81 pairs of coverings 84 of the 1st fuse is 2.5% when above, particularly preferably is, and the non-refractive indices 2 that makes 82 pairs of coverings 84 of the 2nd fuse is for below-0.8%.
Also have, preferably, the specific refractivity difference Δ 3 of 81 pairs the 2nd fuses 82 of the 1st fuse is more than 3.5%.Its reason is that Δ 3 is more than 3.5%, just obtains sufficient non-linear phenomena easily.
In addition, above-mentioned each specific refractivity difference Δ 1, Δ 2, Δ 3 and Δ 4 are defined by following various (6)～(9).
Δ1＝{(n c1-n c)/n c1}·100??????????????????????(6)
Δ2＝{(n c2-n c)/n c2}·100??????????????????????(7)
Δ3＝{(n c1-n c2)/n c1}·100?????????????????????(8)
Δ4＝{(n b-n c)/n b}·100????????????????????????(9)
Herein, above-mentioned various in, n C1Be the largest refractive index of the 1st fuse 81, n C2Be the minimum refractive index of the 2nd fuse 82, n bBe the refractive index that stress is paid parts 85, n cRefractive index for covering 84.Also has n bIs largest refractive index at Δ 4 during for positive symbol, is minimum refractive index during negative symbol.
, as the nonlinear index of expression, can give the nonlinear phase that comes from phase modulation (PM) skew herein, this nonlinear phase skew is represented by following formula (10).
Φ NL＝(2π/λ)·(n 2/A eff)·I·L eff????????????(10)
Herein, Φ NLThe skew of expression nonlinear phase, λ represents wavelength, n 2The expression nonlinear refractive index, A EffThe expression net sectional area, I represents light intensity, L EffThe expression effective length.
Also has the ((n of 2 π/λ) 2/ A Eff) the expression nonlinear factor.
As seen from formula (10), the nonlinear phase skew be increased, nonlinear refractive index n can be increased 2, reduce net sectional area Aeff.The nonlinear refractive index of germanium is bigger than quartz glass, thereby adds germanium in the 1st fuse 81 more, just can increase the nonlinear refractive index n of optical fiber 2Also have, it is poor to increase the 1st fuse 81 and covering 84 specific refractivities, just can reduce net sectional area A EffTherefore, preferably, in the 1st fuse 81, add germanium, improve the refractive index of the 1st fuse 81.
Secondly, Figure 10 represents to simulate the relation of specific refractivity difference Δ 2 of 82 pairs of coverings 84 of specific refractivity difference Δ the 1, the 2nd fuse of the cutoff wavelength λ c that provides and 81 pairs of coverings 84 of the 1st fuse.
Herein, cutoff wavelength λ c is meant the fiber cut off wavelength λ c that G.650 ITU-T (international electrical communication Colaesce) defines.In addition, definition and the measuring method of ITU-TG.650 deferred in the term that defines especially in this instructions.
In addition, the chromatic dispersion of representing wavelength 1550nm place herein is 0ps/nm/km, and the D1/D2=Da that diminishes of the chromatic dispersion gradient at wavelength 1550nm place is the relation of 0.5 o'clock Δ 1 and Δ 2.
As shown in Figure 9, preferably, the specific refractivity difference Δ 2 of the specific refractivity difference Δ 1 of 81 pairs of coverings 84 of the 1st fuse and 82 pairs of coverings 84 of the 2nd fuse satisfies following relationship.
(Δ2)＜-0.52·(Δ1)+1
The relation of the specific refractivity difference Δ 2 of the specific refractivity difference Δ 1 of 81 pairs of coverings 84 of the 1st fuse and 82 pairs of coverings 84 of the 2nd fuse does not satisfy above-mentioned relation, and the absolute value that reduces the chromatic dispersion at wavelength 1550nm place is that 1400nm is following satisfied simultaneously with regard to difficulty with making cutoff wavelength.
By the way, the specific refractivity difference Δ 2 of 82 pairs of coverings 84 of the 2nd fuse be necessary for-below 0.1%.Because the words cutoff wavelength above-0.1% just becomes the long wavelength, promptly more than the 1400nm.Be increased in the 1st fuse 81 germanium that adds and increase the specific refractivity difference Δ 1 of 81 pairs of coverings 84 of the 1st fuse, just can obtain big non-linearly, but, only improve the refractive index of the 1st fuse 81, cutoff wavelength will move to the long wavelength.Therefore, make Δ 2 for below-0.1%.
Also have, stress is paid parts 85 and is located at its both sides with folder every the state of fuse 83 in the present invention.Pay parts 85 as this stress, can adopt for example quartz glass of boracic, or germanic quartz glass etc.
They have the thermal expansivity bigger than pure quartz glass, thereby pay in the parts 85 at stress after the wire drawing and will produce stretcher strain.Like this, will pay stress, thereby the performance polarized wave keeps at the certain orientation of wick area.
Preferably, above-mentioned stress is paid the specific refractivity difference Δ 4 of 85 pairs of coverings 84 of parts for below-0.1% or more than 0.1%.
Its reason is, if surpass-0.1% and less than 0.1%, diminishes with the refringence of covering 84, thereby is difficult to distinguish covering 84 and pays parts 85 with stress, is difficult to discern the position that stress is paid parts 85.
The result, for example, connect polarized wave of the present invention and keep optical fiber 810 each other, or polarized wave of the present invention is when keeping optical fiber 810 and other polarized wave to keep optical fiber, for the polarized wave front of alignment two optical fiber, must discern stress and pay the connection more afterwards of parts 85 positions, and as mentioned above, if be difficult to discern the position that stress is paid 85,85 pairs of coverings 84 of parts, connection work is just very difficult.
Pay parts 85 as stress, preferably added the quartz glass of boron.The quartz glass that has added boron has the refractive index lower than pure quartz glass.
Owing to must keep optical fiber to show non-linear phenomena as wide as possible at the polarized wave that is used for non-linear phenomena, thereby preferably increase the refringence of the 1st fuse 81 and the 2nd fuse 82 and covering 84, thereby increase nonlinear factor.At this moment, the refractive index ratio covering 84 that the stress that is located at cladding regions is paid parts 85 is high, just is unfavorable for increasing effective fuse sectional area A Eff, obtain big non-linear phenomena.Therefore, preferably adopt at stress and pay the quartz glass that has added boron in the parts 85 with refractive index lower than pure quartz glass.
Also have, the specific refractivity difference Δ 4 that this stress is paid 85 pairs of coverings 84 of parts more preferably-0.8%～-0.2%.Its reason is, and is non-linear in order to obtain, the specific refractivity difference that stress is paid 85 pairs of coverings 84 of parts preferably-below 0.2%, on the other hand,, be-0.9% such value less than-0.8%, the making itself that stress is paid parts 85 just becomes and is not easy.
Have, as shown in Figure 8, the diameter of the 1st fuse 81 is made as D1 again, and folder is located at interval that 2 stress of its both sides pay parts 85 when being made as R every fuse 83, and the R/D1 value must be made as 2.5～10.More preferably be made as more than 2.5 below 3.7.
Its reason is, R/D1 surpasses 10, just can not reduce the polarized wave cross-talk, and it is long to reduce beat.
Herein, as shown in Figure 9, the diameter D1 of the 1st fuse 81 is made as the length of the line of the position that is connected the refractive index that equates with covering 84 in the 1st fuse 81.Also have, the diameter D2 of the 2nd fuse 82 is made as in the borderline region of the 2nd fuse 82 and covering 84, is connected to become the length of line of position of 1/2 refractive index of Δ 2.
Have, the interval R that 2 stress is paid 85 of parts represents that 2 stress pay the shortest interval of parts 85 again, is made as the length of line of the position of 1/2 the refractive index that is connected to become Δ 4.
By the way, as mentioned above, R/D1 being made as below 3.7, just can obtaining fully little polarized wave cross-talk, is preferred.
, polarized wave of the present invention that increased the specific refractivity difference of the 1st fuse and covering keeps in the optical fiber in order to increase non-linear, and the diameter of the 1st fuse 81 is compared and will be diminished with common single-mode fiber.Therefore too reduce the value of R/D1, the processing when stress being set paying parts 85 just becomes difficult.Therefore the value of R/D1 is necessary for more than 2.5.Also have, R/D1 is less than 2.5, and stress is paid parts 85 just too close the 2nd fuses 82, and contact variation, thereby the difficulty still of the processing when stress being set paying parts 85 are not preferred.
Also have, the interval R that stress is paid parts 85 preferably 7 μ m to 17 μ m.Its reason is, the interval R that stress is paid parts 85 surpasses 17 μ m, just is difficult to reduce the polarized wave cross-talk, and it is long to be difficult to reduce beat.
On the other hand, stress is paid the interval R of parts 85 less than 7 μ m, and stress is paid parts 85 just too close the 2nd fuses 82, and polarized wave keeps the manufacturing of optical fiber just to become difficult.Particularly, keep optical fiber in order to obtain this polarized wave, perforate on the fibre parent material before wire drawing, when stress was paid parts 85 these holes of insertion, fibre parent material became different and breaks, and this is the problem place.
Also have, in the present invention, preferably, polarized wave keep the polarized wave cross-talk at the length 100m of optical fiber and wavelength 1550nm place be-below the 20dB.Its reason is, surpasses-20dB/100m, just can not obtain sufficient polarized wave maintenance performance.
Have, the beat at wavelength 1550nm place is long preferably below the 5mm again.Its reason is that the long 5mm that surpasses of beat probably just can not obtain sufficient polarized wave and keep performance.
Also have, the polarized wave maintenance optical fiber of the present invention preferably chromatic dispersion at wavelength 1550nm place is-9～9ps/nm/km.Its reason is, so-called quartz under polarized wave of the present invention keeps optical fiber is in the optical fiber, be that the minimum wavelength that is called C-band 1.55 μ m band is that the wavelength band territory at center is when carrying out signal Processing with the loss, the polarized wave at wavelength 1550nm place keeps CHROMATIC DISPERSION IN FIBER OPTICS less than-9ps/nm/km, utilizes the light signal treatment effeciency of non-linear phenomenas such as wavelength conversion and wave shaping to descend.
Also have,, utilize the light signal treatment effeciency of non-linear phenomenas such as wavelength conversion and wave shaping can reduce too if chromatic dispersion surpasses 9ps/nm/km.Chromatic dispersion more preferably-1～1ps/nm/km.
In addition, the chromatic dispersion gradient at wavelength 1550nm place 0.029ps/nm preferably 2Below/the km.Utilize the light signal of non-linear phenomena to handle the great role that is subjected to CHROMATIC DISPERSION IN FIBER OPTICS, chromatic dispersion gradient surpasses 0.029ps/nm 2/ km, the wavelength dependency of chromatic dispersion become big, and it is difficult that the stable signal Processing in big wavelength coverage just becomes.
For example, utilize in the wavelength conversion of four ripples mixing, the pump wavelength dependence that will produce conversion band territory becomes big problem.Chromatic dispersion gradient is 0.019ps/nm more preferably 2Below/the km, 0.009ps/nm preferably again 2Below/the km.
Also have, polarized wave of the present invention keeps optical fiber, and the bending loss of the diameter 10mm at wavelength 1550nm place is preferably below the 0.1dB/m.Bending loss is that 0.1dB/m is above, and when optical fiber had been coiled, it is big that loss just may become.
Secondly, illustrate that according to simulated behavior polarized wave of the present invention keeps optical fiber.
As mentioned above, the specific refractivity difference Δ 2 of 82 pairs of coverings 84 of the 2nd fuse be necessary for-below 0.1%.Surpass-0.1%, cutoff wavelength just becomes the long wavelength, promptly more than the 1400nm.By increasing in the 1st fuse 81 germanium that adds, increase the specific refractivity difference Δ 1 of 81 pairs of coverings 84 of the 1st fuse, obtain big non-linearly, but, only improve the refractive index of the 1st fuse 81, cutoff wavelength will move to the long wavelength.
But,,, can prevent that also cutoff wavelength from becoming the long wavelength even improve the refringence of the 1st fuse 81 by reducing the refringence of the 2nd fuse 82.Particularly preferably be, the specific refractivity difference that makes 82 pairs of coverings 84 of the 2nd fuse is for below-0.8%.For the specific refractivity difference that makes 82 pairs of coverings 84 of the 2nd fuse is below-0.8%, for example, to make the quartz glass soot body that becomes the 2nd fuse 82 carry out vitrifacation with pressurized state under the atmosphere of fluorine-containing or fluorine compounds and get final product.
So, during the ratio D1/D2=Da of the diameter D2 of the diameter D1 of the 1st fuse 81 and the 2nd fuse 82, D1/D2 is necessary for 0.3～0.8.Preferably 0.4～0.7.
Polarized wave for structure shown in Figure 8 keeps optical fiber, when the ratio D1/D2=Da of D2 of the diameter of the diameter D1 of the 1st fuse 81 and the 2nd fuse 82 has been changed, promptly the parameter beyond the 1st fuse footpath D1 and the 2nd fuse footpath D2 is fixed as the value of embodiment 1, the variation of chromatic dispersion gradient, net sectional area Aeff and cutoff wavelength λ c when the ratio D1/D2=Da of the 1st fuse footpath D1 and the 2nd fuse footpath D2 has been changed, be Simulation result, be illustrated respectively among Figure 11, Figure 12 and Figure 13.
In addition, in this Figure 11～13, adjusted the 1st fuse footpath D1 and the 2nd fuse footpath D2, the chromatic dispersion that makes the 1550nm place is zero.
As can be seen from Figure 11, Da (D1/D2) surpasses at 0.8 o'clock, and Da (D1/D2) is lower than 0.3, and the value of chromatic dispersion gradient will be bigger than allowing scope.
Also have, as can be seen from Figure 12, Da (D1/D2) is more little, net sectional area A EffJust more little.That is, the mode field footpath also diminishes, and is favourable for obtaining high nonlinear constant.It can also be seen that Da (D1/D2) surpasses 0.8, A EffWill be bigger than allowing scope.
As can be seen from Figure 13, Da (D1/D2) is more little, and cutoff wavelength λ c just can shorten more.As can be seen, Da surpasses 0.8, and cutoff wavelength just becomes more than the 1400nm.
When having considered above-mentioned analog result, made the polarized wave that the Embodiment B 1～B3 of table 5, table 6 represents respectively and kept optical fiber.Also have, the result that this each polarized wave that produces keeps the characteristic of optical fiber has been measured in table 7 expression.In addition, in table 7, the characteristic beyond the cutoff wavelength is used for representing the characteristic at wavelength 1550nm place.
The polarized wave of all embodiment keeps optical fiber can both make the little value of polarized wave cross-talk for wishing, promptly-20dB/100m following-below the 28dB/100m, and nonlinear factor is also for more than the above 15.5/W/Km of the 15/W/Km of the value of wishing.In addition, beat is long also can be in the scope of 4.3～4.7mm, promptly below the 5mm of Xi Wanging.
As can be seen, like this, each polarized wave of the various embodiments described above B1～B3 keeps optical fiber, and the polarized wave cross-talk is little, and is non-linear also outstanding, therefore is that the polarized wave that is suitable for utilizing the light signal of nonlinear optical phenomena to handle keeps optical fiber.
Table 5
??Δ1 ??Δ2 The 1st fuse α The 1st fuse footpath The 2nd fuse footpath ??D1/D2＝Da The covering footpath
??％ ??％ ??μm ??μm ??μm
Embodiment B
1 ??2.4 ??-0.55 ??4 ??4.2 ??7.6 ??0.56 ??125
Embodiment B 2 ??2.9 ??-1.0 ??5 ??3.6 ??9.9 ??0.365 ??125
Embodiment B 3 ??2.8 ??-1.0 ??5 ??3.6 ??6.5 ??0.55 ??125
Table 6
Stress is paid parts space R The 1st fuse is directly paid the ratio R/D1 of parts space with stress Stress is paid the parts external diameter ??Δ4
??μm ??μm ??％
Embodiment B
1 ??20 ??4.5 ??34 ??-0.53
Embodiment B 2 ??16 ??4.4 ??34 ??-0.53
Embodiment B 3 ??12 ??3.4 ??34 ??-0.53
Table 7
Nonlinear factor Chromatic dispersion Chromatic dispersion gradient Cutoff wavelength The mode field footpath Cross-talk Beat is long Loss Bending loss
??/W/km ??ps/nm/km ??ps/nm 2/km ??nm ??μm ??dB/100m ??mm ??dB/km ??dB/m
Measure wavelength ??1550nm ??1550nm ??1550nm ??1550nm ??1550nm ??1550nm ??1550nm ??1550nm
Embodiment B
1 ??15.5 ??0.3 ??0.026 ??1310 ??4.3 ??-33 ??4.5 ??0.79 ??0.0
Embodiment B 2 ??25.1 ??-0.5 ??0.024 ??1260 ??3.2 ??-28 ??4.7 ??2.5 ??0.0
Embodiment B 3 ??24.2 ??1.3 ??0.017 ??1232 ??3.3 ??-41 ??4.3 ??2.7 ??0.0
In addition, the polarized wave shown in the various embodiments described above keeps the manufacturing of optical fiber to adopt following method to carry out.This method be for example with the VAD method make by by doped germanium the specific refractivity difference of pure quartz glass being adjusted to the 1st core member that 2% quartz glass for example constitutes.On the periphery of this core member, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid.Then containing Cl 2He in to its heating, make its dehydration, containing SiF again 4With under the atmosphere of He to its heating, make it become clear glass, like this 2nd core member that constitutes with regard to the quartz glass that is provided with by the fluorine that mixed.
Again on this periphery, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid, is then containing Cl 2He in to its heating, make its dehydration, containing under the atmosphere of He, make it become clear glass again to its heating, so just be provided with the covering spare that constitutes by quartz glass.
Fibre parent material below so just having obtained: this fibre parent material for example is being on the 1st core member periphery of 2.8% to the specific refractivity difference of covering, be provided with to the specific refractivity difference of covering for-1.0% doping the 2nd core member of fluorine, on its periphery, be provided with the covering spare that constitutes by quartz glass again.
At the two ends of the fibre parent material that obtains, in order to prevent to break, welding has connected the parts that are made of quartz glass.Like this, at the two ends of fibre parent material, connect the parts that are made of quartz glass, the be full of cracks generation and the breakage of the fibre parent material in the operation afterwards will reduce.
The welding of quartz glass member made is connected after the fibre parent material two ends, in the part of the quartz glass parts at the two ends that connected, to the direction of principal axis of fibre parent material vertically, make section flatly with its cut-out.Then the tabular surface from having cut off is clipping two side hole of core member, pays parts so that insert stress.Then, in this hole, insert preprepared the attaching the stress that quartz glass constitutes by boron and paying parts of the external diameter littler that have than the internal diameter in hole.
Pay in the mother metal integrated furnace of top that the fibre parent material of parts imports the mother metal input port that is located at fiber drawing furnace having inserted stress, heat, make both softening, integrated.With stress pay parts integrated the temperature of fibre parent material descend and sclerosis because the significant difference that fibre parent material and stress are paid the thermal expansivity of parts, thereby worry that very fibre parent material breaks.Therefore, it is integrated afterwards not to its cooling that fibre parent material and stress are paid parts, and directly import fiber drawing furnace, and optical fiber external diameter in accordance with regulations carries out wire drawing, obtains polarized wave and keeps optical fiber.
Keep being provided with for example by uv-hardening resin at once after the wire drawing on the optical fiber at the glass polarized wave after the wire drawing, or the resinous coat of thermosetting resin formation.When resinous coat is uv-hardening resin, use the periphery application of resin of coating mold at glass polarized wave maintenance optical fiber, irradiation ultraviolet radiation makes after its sclerosis, is rolled into volume.
But, polarized wave of the present invention keeps the manufacturing of optical fiber to be not limited to above-mentioned manufacture method, and for example as the synthetic method of fibre parent material, much less, except the VAD method, existing gas phase growth method such as MCVD method or OVD method also can be used.
, keep the polarized wave of the invention described above optical fiber to be rolled into the volume of the about 180mm of external diameter herein, obtain wavelength shifter.Characteristic to this wavelength shifter is studied, and it has represented outstanding wavelength conversion characteristic at wide band.
C: the high non-line spare optical fiber of low transmission loss-type
Embodiment C 1
At first, be ready to by doped germanium the 1st core member that the silica glass of the specific refractivity difference of pure silicon stone having been adjusted to 2.8% is constituted.On the periphery of this core member, to silicon tetrachloride (SiCl 4) gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid, then containing Cl 2He in to its heating, make its dehydration, containing SiF again 4With under the atmosphere of He to its heating, make it become clear glass, like this 2nd core member that constitutes with regard to the silica glass that is provided with by the fluorine that mixed.
Secondly, on the periphery of the 2nd fuse, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid, is then containing Cl 2He in to its heating, make its dehydration, containing under the atmosphere of He, make it become clear glass again to its heating, form the covering that constitutes by pure silicon stone.
Fibre parent material below so just having obtained: being configured to of this fibre parent material, be on the periphery of 2.8% the 1st fuse in relative index of refraction to pure silicon stone, be provided with to the relative index of refraction of pure silicon stone for-0.55% doping the 2nd fuse of fluorine, on its periphery, have the covering that constitutes by pure silicon stone again.
The mother metal that obtains carries out wire drawing by fiber drawing furnace, is the optical fiber of 90 μ m with regard to the external diameter that has obtained covering.The characteristic of the optical fiber that following table 8 expressions obtain.
Embodiment C 2
Except the external diameter of covering is 80 μ m, identical with Embodiment C 1, produce optical fiber with embodiment 1 identical construction.
Embodiment C 3
Except the external diameter of covering is 100 μ m, identical with Embodiment C 1, produce optical fiber with embodiment 1 identical construction.
Comparative example C1
Except the external diameter of covering is 125 μ m, identical with Embodiment C 1, produce optical fiber with embodiment 1 identical construction.
Comparative example C2
Except the external diameter of covering is 120 μ m, identical with Embodiment C 1, produce optical fiber with embodiment 1 identical construction.
Comparative example C3
Except the external diameter of covering is 130 μ m, identical with Embodiment C 1, produce optical fiber with embodiment 1 identical construction.
In addition, for Embodiment C 2, C3, comparative example C1～C3, the thick adjustment of the covering by mother metal, the 1st fuse footpath when having made the optical fiber of external diameter 80,100,120,125,130 μ m is identical with Embodiment C 1 with the 2nd fuse footpath.
The characteristic of the optical fiber that following table 8 expressions obtain.In addition, the measurement wavelength of characteristic is beyond the cutoff wavelength, to be 1550nm, and bending loss is the value at diameter 5mm.
Table 8
Embodiment C 1 Embodiment C 2 Embodiment C 3 Comparative example C1 Comparative example C2 Comparative example C3
Structure The 1st fuse Δ ??％ ??2.8 ??2.8 ??2.8 ??2.8 ??2.8 ??2.8
The 1st fuse footpath D1 ??μm ??3.8 ??3.9 ??4.0 ??3.8 ??3.9 ??4.0
The 2nd fuse Δ ??％ ??-0.55 ??-0.55 ??-0.55 ??-0.55 ??-0.55 ??-0.55
The 2nd fuse footpath D2 ??μm ??6.4 ??6.5 ??6.6 ??6.4 ??6.5 ??6.6
Covering spare Pure silicon stone Pure silicon stone Pure silicon stone Pure silicon stone Pure silicon stone Pure silicon stone
The covering external diameter ??μm ??90 ??80 ??100 ??125 ??120 ??130
The resinous coat footpath ??μm ??145 ??130 ??150 ??250 ??245 ??250
??D1/D2 ??0.59 ??0.60 ??0.61 ??0.59 ??0.60 ??0.61
Characteristic ※ Loss ??dB/km ??0.83 ??0.79 ??0.78 ??1.05 ??1.02 ??1.01
Nonlinear constant ??×10 -10/W ??53.2 ??51.5 ??49.7 ??51.2 ??50.8 ??49.5
Chromatic dispersion ??ps/nm/km ??-1.1 ??-0.2 ??0.6 ??-1.2 ??-0.3 ??0.8
Chromatic dispersion gradient ??ps/nm 2/km ??0.0148 ??0.0166 ??0.017 ??0.0149 ??0.0165 ??0.172
Cutoff wavelength ??nm ??1384 ??1416 ??1445 ??1394 ??1422 ??1449
Bending loss ??dB/m ??＜0.05 ??＜0.05 ??＜0.05 ??＜0.05 ??＜0.05 ??＜0.05
※@1550nm
Embodiment C 4
Except that the 1st core member has been used the 1st core member that the silica class glass that the specific refractivity difference of pure silicon stone is adjusted into 2.0% is made of doped germanium, identical with Embodiment C 1, obtain the optical fiber of the structure shown in the following table 9.The characteristic of the optical fiber that following table 9 expressions obtain.
Comparative example C4
Except that the 1st core member has been used the 1st core member that the silica class glass that the specific refractivity difference of pure silicon stone is adjusted into 2.0% is made of doped germanium, identical with Embodiment C 1, obtain the optical fiber of the structure shown in the following table 9.The characteristic of the optical fiber that following table 9 expressions obtain.
Table 9
Embodiment C 4 Comparative example C4
Structure The 1st fuse Δ ??％ ??2.0 ??2.0
The 1st fuse footpath ??μm ??4.3 ??4.4
The 2nd fuse Δ ??％ ??-0.55 ??-0.55
The 2nd fuse footpath ??μm ??7.7 ??7.8
Covering spare Pure silicon stone Pure silicon stone
The covering external diameter ??μm ??90 ??125
The resinous coat footpath ??μm ??145 ??250
??D1/D2 ??0.55 ??0.55
Characteristic ※ Loss ??dB/km ??0.33 ??0.49
Nonlinear constant ??×10 -10/W ??53.2 ??51.5
Chromatic dispersion ??ps/nm/km ??-0.8 ??0.3
Chromatic dispersion gradient ??ps/nm 2/km ??0.014 ??0.016
Cutoff wavelength ??nm ??1150 ??1210
Bending loss ??dB/m ??＜0.05 ??＜0.05
※@1550nm
The measurement wavelength of characteristic is 1550nm beyond cutoff wavelength, bending loss is the value at diameter 5mm.From above-mentioned table 8, table 9 as can be seen, the optical fiber that Embodiment C 1～C4 is related, loss reduces, and is outstanding.By contrast, the optical fiber that comparative example C1～C4 is related, loss is big.
As described above, optical fiber of the present invention, nonlinear constant n 2/ Aeff is 20 * 10 -10More than/the W, the absolute value of the wavelength dispersion at 1550nm place is below the 20ps/nm/km, bending loss is below the 0.1dB/m, the external diameter of covering is 70～110 μ m, thereby has high non-linear and low loss simultaneously, can cause non-linear phenomena effectively, and can realize densification, thereby the light signal that utilizes non-linear phenomena is handled is useful.
In the one or both ends of above-mentioned low-loss highly nonlinear optical fiber, single-mode fiber or the dispersion-shifted fiber of welding external diameter 120～130 μ m, and the optical fiber that this weld portion enforcement heat treated is formed also is fine.Figure 14, Figure 15 represent this situation.Welding is incorporated into the single-mode fiber of covering external diameter 120～130 μ m (or the dispersion-shifted fiber of covering external diameter 120～130 μ m or Aeff is 20 μ m optical fiber 141 of the present invention by connecting portion 143 2Above optical fiber) 142.The fuses of 144 expressions in the optical fiber of the present invention of Figure 15,146 expressions are heated the fuse of the connecting portion of having handled, the fuse in the 145 expression optical fiber 105.
The covering external diameter is made as the words of 70～110 μ m, connection at the scene with other optical fiber is just very difficult, and it is big that junction loss becomes, and highly nonlinear optical fiber involved in the present invention aim at the single-mode fiber of external diameter 120～130 μ m or dispersion-shifted fiber in advance separately the center and welding, weld portion is carried out heat treated, thereby can make with other optical fiber optical fiber of ease of connection at the scene.
Preferably, for highly nonlinear optical fiber involved in the present invention and the optical fiber of wanting external diameter 120～130 μ m of welding, make centrally aligned separately.Fiber optic hub is separately aimed at, just can be reduced junction loss.Also have, preferably, after the welding weld portion is carried out heat treated.Carry out heat treated after the welding, the adulterant of connecting portion fuse will spread, and the mode field footpath will enlarge, thereby just can reduce the junction loss of weld portion.
Also have, in the optical fiber involved in the present invention, as 70～110 μ m, thereby can reduce the covering footpath to comprise and to be rolled into web-like compactly by resin-coated external diameter.Optical fiber involved in the present invention is rolled into below the maximum coil diameter 20cm, the subsystem assembly used with, wavelength conversion with, light 3R of following and for example light 2R that harvesting is got up of 18cm preferably, can utilize the light signal of high non-linearity phenomenon to handle, and have compact this advantage.
E: the highly nonlinear optical fiber of improved efficiency type
Study routine E1
On the 1st core member that the silica glass of the specific refractivity difference of pure silicon stone having been adjusted to 2.0% is constituted by doped germanium, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid, is then containing Cl 2He in to its heating, make its dehydration, containing SiF again 4With under the atmosphere of He to its heating, make it become clear glass.
Secondly, thereon, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid, is then containing Cl 2He in to its heating, make its dehydration, containing under the atmosphere of He, make it become clear glass again to its heating.
Fibre parent material below so just having obtained: this fibre parent material is on the periphery of 2.0% the 1st fuse in the relative index of refraction to pure silicon stone, be provided with to the relative index of refraction of pure silicon stone for-0.55% doping the 2nd fuse of fluorine, on its periphery, have the covering that constitutes by pure silicon stone again.In addition, the 1st fuse footpath D1 is made as 0.56 to the ratio Da of the 2nd fuse footpath D2 herein.
The mother metal of Huo Deing carries out wire drawing by fiber drawing furnace like this, thereby the external diameter that obtains covering is the optical fiber of 125 μ m.Figure 19 represents the refractive index profile shape of the optical fiber that obtains, and Figure 20 represents cross-sectional configuration.Constitute by the 1st fuse the 201, the 2nd fuse 202, covering 203 and resinous coat 204.Also has the characteristic of the optical fiber that following table 10 expressions obtain.
Study example E2, E4～E6
Except that refractive index that has changed core member and Da, example E1 is identical with studying, and obtains optical fiber.Figure 19 represents the refractive index profile shape of the optical fiber that obtains, and Figure 20 represents cross-sectional configuration.Also has the characteristic of the optical fiber that following table 10 expressions obtain.
Study routine E3
On the 1st core member that the silica glass of the specific refractivity difference of pure silicon stone having been adjusted to 2.0% is constituted by doped germanium, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous plastid, is then containing Cl 2He in to its heating, make its dehydration, containing SiF again 4With under the atmosphere of He to its heating, make it become clear glass.
Secondly, thereon, to SiCl 4Gas carries out flame hydrolysis, and carbon black is piled up, and forms porous matter covering, is then containing Cl 2He in to its heating, make its dehydration, containing SiF again 4With make it become clear glass under the atmosphere of He.
So just obtained on the relative index of refraction to pure silicon stone is the periphery of 2.0% the 1st fuse, to have to the relative index of refraction of pure silicon stone fibre parent material for-0.55% the covering of mixing fluorine.
The fibre parent material of Huo Deing carries out wire drawing by fiber drawing furnace like this, thereby the external diameter that obtains covering is the optical fiber of 125 μ m.Figure 21 represents the refractive index profile shape of the optical fiber that obtains, and Figure 22 represents cross-sectional configuration.Constitute by fuse 221, covering 222 and resinous coat 223.Also has the characteristic of the optical fiber that following table 10 expressions obtain.
Table 10
Study example
??E1 ??E2 ??E3 ??E4 ??E5 ??E6
Structure/size ??Δ1 ??％ ??2 ??2 ??2.55 ??2.8 ??2.8 ??2
The 1st fuse footpath D1 ??μm ??4.3 ??4.3 ??4.0 ??3.9 ??3.9 ??3.9
??Δ2 ??％ ??-0.55 ??-0.55 ??- ??-0.55 ??-0.55 ??-0.55
The 2nd fuse footpath D2 ??μm ??7.8 ??40.5 ??- ??6.5 ??6.5 ??6.5
??D1/D2 ??- ??0.56 ??0.1 ??- ??0.6 ??0.6 ??0.4
The covering external diameter ??μm ??125 ??125 ??125 ??125 ??90 ??125
The coating external diameter ??μm ??245 ??245 ??245 ??245 ??150 ??185
Characteristic (notes) Loss ??dB/km ??0.48 ??0.41 ??0.35 ??0.93 ??0.86 ??0.38
Nonlinear constant n 2/A eff ??×10 -10/W ??31 ??27.6 ??33.6 ??46.9 ??59.4 ??30.4
??(2πλ)(n 2/A eff) ??/W/km ??12.6 ??11.2 ??13.6 ??19.0 ??24.1 ??12.3
Chromatic dispersion ??ps/nm/km ??-0.2 ??-11 ??-1 ??1.5 ??0.2 ??0.1
(notes) measure wavelength is 1550nm.
The long embodiment of various optical fiber of the optical fiber that studies routine E1～E6 has been adopted in following table 11 expressions.
Table 11
Embodiment
The optical fiber kind Embodiment ??E1 ??E2 ??E3 ??E4 ??E5 ??E6
Optical fiber is long ??km ??2 ??10 ??1 ??2 ??0.6 ??20
??(2π/λ)(n 2/A eff) [1-exp (aL)]/a (annotating 1) ??W -1 ??22 ??76 ??13 ??32 ??1.4 ??118
Bending loss (annotating 1) (annotating 2) ??dB/m ??＜0.1 ??＜0.1 ??＜0.1 ??＜0.1 ??＜0.1 ??＜0.1
(annotating 1) measurement wavelength is 1550nm.
(annotating 2) coil diameter 5mm.
For the optical fiber that obtains, calculate the ((n of 2 π/λ) by the long L of various optical fiber 2The value of/Aeff) [1-exp (aL)]/a is promptly from the Φ of phase modulation (PM) NL/I, as Figure 17 and shown in Figure 180.
Embodiment E 1～E3, E6 have adopted γ=((n of 2 π/λ) 2/ Aeff) at the example of the optical fiber of the scope of 8～17/W/km, as can be seen from Figure 17, for these optical fiber, the long 30km that surpasses of optical fiber, even it is long to increase optical fiber again, the ((n of 2 π/λ) 2The value of/Aeff) [1-exp (aL)]/a also increases hardly.
Embodiment E 4, E5 have adopted γ=((n of 2 π/λ) 2/ Aeff) at the example of the optical fiber of the scope of 17～27/W/km, as can be seen from Figure 17, for these optical fiber, optical fiber long surpass 10km scope, even it is long to increase optical fiber again, the ((n of 2 π/λ) 2The value of/Aeff) [1-exp (aL)]/a also increases hardly.
Industrial applicibility
Describe in detail as above, according to the present invention, just can obtain following optical fiber: λ ((n of 2 π/λ) when the scope of 1500nm～1600nm2The value of/Aeff) [1-exp (aL)]/a satisfies more than the 1/W, the absolute value of the wavelength dispersion at wavelength 1550nm place is below the 30ps/nm/km, the bending loss at wavelength 1550nm place is below the 0.5dB/m, thereby can effectively utilize the signal of non-linear phenomena to process. And, adopted the optical signal device of this optical fiber to consist of like that by Fig. 7.
Also have, λ when the scope of 1500nm～1600nm the ((n of 2 π/λ)2/ Aeff) and L, a be located at the scope of regulation, just can obtain to utilize the optical fiber of the signal processing of non-linear phenomena.

Claims (42)

1. an optical fiber is characterized in that, the chromatic dispersion gradient at wavelength 1550nm place is-0.01～0.01ps/nm 2/ km, the absolute value of the chromatic dispersion at wavelength 1550nm place is 10ps/nm/km and following, and the nonlinear constant at wavelength 1550nm place is 30 * 10 -10More than/W reaches.
2. optical fiber according to claim 1 is characterized in that, the chromatic dispersion gradient at wavelength 1550nm place is-0.005～0.005ps/nm 2/ km.
3. optical fiber according to claim 1 and 2 is characterized in that, the nonlinear constant at wavelength 1550nm place is 40 * 10 -10More than/W reaches.
4. according to any described optical fiber in the claim 1～3, it is characterized in that cutoff wavelength λ c is 1450nm and following, net sectional area Aeff is 12 μ m 2And below.
5. optical fiber according to claim 4 is characterized in that, net sectional area Aeff is 10 μ m 2And below.
6. according to any described optical fiber in the claim 1～5, it is characterized in that the absolute value of the chromatic dispersion at wavelength 1550nm place is 5ps/nm/km and following.
7. according to any described optical fiber in the claim 1～6, it is characterized in that the optical fiber of the random wave strong point in wavelength 1510～1590nm is 1ps/nm/km and following than the maximal value of the dispersion values of length direction and the difference of minimum value using in the long total length of 1 optical fiber.
8. optical fiber according to claim 7 is characterized in that, the optical fiber of the random wave strong point in wavelength 1510～1590nm is 0.2ps/nm/km and following than the maximal value of the dispersion values of length direction and the difference of minimum value using in the long total length of 1 optical fiber.
9. according to any described optical fiber in the claim 1～8, it is characterized in that having: the 1st fuse has the refractive index higher than pure silicon stone; The 2nd fuse is located at the periphery of the 1st fuse, has the refractive index lower than pure silicon stone; And covering, in the periphery of the 2nd fuse, lower than the 1st fuse refractive index, than the 2nd fuse refractive index height, the outer diameter D 1 of described the 1st fuse is 2～5 μ m, the ratio D1/D2=Da of the outer diameter D 1 of described the 1st fuse and the outer diameter D 2 of described the 2nd fuse be 0.3 and above, 0.8 and below.
10. optical fiber according to claim 9 is characterized in that, the ratio D1/D2=Da of the outer diameter D 1 of described the 1st fuse and the outer diameter D 2 of described the 2nd fuse be 0.4 and above, 0.7 and below.
11., it is characterized in that the specific refractivity difference Δ 1 of described the 1st fuse and covering is 2.0～5.0% according to claim 9 or 10 described optical fiber, the specific refractivity difference Δ 2 of described the 2nd fuse and covering is-1.4～-0.7%.
12. optical fiber according to claim 11 is characterized in that, the specific refractivity difference Δ 1 of described the 1st fuse and covering is 2.4～4.0%, and the specific refractivity difference Δ 2 of described the 2nd fuse and covering is-1.2～-0.8%.
13. according to any described optical fiber in the claim 9～12, it is characterized in that the refractive index profile shape of described the 1st fuse is α curve, α be 3.0 and more than.
14. optical fiber according to claim 13 is characterized in that, the refractive index profile shape of described the 1st fuse is α curve, α be 6.0 and more than.
15. a light signal processing device is characterized in that, has adopted any described optical fiber in the described claim 1～14.
16. light signal processing device according to claim 15 is characterized in that, described light signal processing device is an optical wavelength changer.
17. light signal processing device according to claim 15 is characterized in that, described light signal processing device is a pulse shortener.
18. optical fiber, have fuse, be located at this fuse periphery covering and be located at the quartz glass class that 2 stress of the both sides of described fuse are paid parts, it is characterized in that, the nonlinear factor at wavelength 1550nm place is more than 15/W/Km reaches, cutoff wavelength is 1500nm and following, the chromatic dispersion at wavelength 1550nm place is-9ps/nm/km to 9ps/nm/km that the chromatic dispersion gradient at wavelength 1550nm place is 0.029ps/nm 2/ km and following, and the polarized wave cross-talk at wavelength 1550nm place is-20dB/100m and following.
19. optical fiber according to claim 18 is characterized in that, cutoff wavelength is 1400nm and following, and the chromatic dispersion gradient at wavelength 1550nm place is 0.019ps/nm 2/ km and following, the beat at wavelength 1550nm place is long to be 5mm and following, and the bending loss of the diameter 10mm at wavelength 1550nm place is 0.1dB/m and following.
20. according to claim 18 or 19 described optical fiber, it is characterized in that, described fuse is made of the 1st fuse that is positioned at central part and the 2nd fuse that is located at the periphery of the 1st fuse, described the 2nd fuse has than the low refractive index of described the 1st fuse, and described covering has than described the 2nd fuse height and than the low refractive index of described the 1st fuse.
21. optical fiber according to claim 20, it is characterized in that, described the 1st fuse to the specific refractivity difference Δ 1 of described covering be 1.8% and more than, described the 2nd fuse to the specific refractivity difference Δ 2 of described covering be-0.1% and below, the ratio R/D1 that described stress is paid the diameter D1 of the interval R of parts and described the 1st fuse is 2.5 to 10, and the ratio D1/D2 of the diameter D1 of described the 1st fuse and the diameter D2 of described the 2nd fuse is 0.3 to 0.8.
22. optical fiber according to claim 21 is characterized in that, the ratio R/D1 that described stress is paid the diameter D1 of the interval R of parts and described the 1st fuse is 2.5 to 3.7.
23., it is characterized in that the interval R that described stress is paid parts is 7 μ m to 17 μ m according to claim 21 or 22 described optical fiber.
24., it is characterized in that the ratio D1/D2 of the diameter D1 of described the 1st fuse and the diameter D2 of described the 2nd fuse is 0.4 to 0.7 according to any described optical fiber in the claim 21～23.
25., it is characterized in that described the 1st fuse satisfies following relationship to the specific refractivity difference Δ 1 of described covering and described the 2nd fuse to the specific refractivity difference Δ 2 of covering according to any described optical fiber in the claim 20～24:
(Δ2)＜-0.52·(Δ1)+1。
26. according to any described optical fiber in the claim 21～25, it is characterized in that, described the 2nd fuse to the specific refractivity difference Δ 2 of described covering be-0.8% and below, described the 1st fuse to the specific refractivity difference Δ 3 of described the 2nd fuse be 3.5% and more than.
27. according to any described optical fiber in the claim 18～26, it is characterized in that, it is the quartz glasss that added boron that described stress is paid parts, described covering is the quartz glass that has added fluorine, described stress pay parts to the specific refractivity difference Δ 4 of described covering for-0.1% and following or 0.1% and more than.
28. an optical wavelength changer is characterized in that, has used the described optical fiber of claim 18.
29. an optical fiber is made of fuse and covering, is characterised in that nonlinear constant n 2/ Aeff is 20 * 10 -10More than/W reached, the absolute value of the wavelength dispersion at wavelength 1550nm place was 20ps/nm/km and following, and bending loss is 0.1dB/m and following, and the wavelength dispersion slope at wavelength 1550nm place is 0.019ps/nm 2/ km and following, the external diameter of described covering are 70～110 μ m.
30. optical fiber according to claim 29 is characterized in that, cutoff wavelength is 1350nm and following.
31. according to claim 29 or 30 described optical fiber, it is characterized in that the optical fiber of the random wave strong point in wavelength 1510～1590nm is that amplitude of fluctuation is 3ps/nm/km and following using in the long total length of 1 optical fiber than the maximal value of the wavelength dispersion of length direction and the difference of minimum value.
32. according to any described optical fiber in the claim 29～31, it is characterized in that, described fuse has the 1st fuse that is positioned at central part at least, and described the 1st fuse is made of the quartz glass that contains germanium oxide, described fuse to the specific refractivity difference of described covering be 1.5% and more than.
33. optical fiber according to claim 32 is characterized in that, described fuse to the specific refractivity difference of described covering be 2.5% and more than.
34. according to any described optical fiber in the claim 29～33, it is characterized in that, described fuse is made of the 2nd fuse of the periphery of the 1st fuse that is positioned at central part and covering the 1st fuse, described covering is made of pure silicon stone glass or the silica class glass that has near the refractive index of pure silicon stone, and described the 2nd fuse is-1.2～-0.4% to the specific refractivity difference of described covering.
35. optical fiber according to claim 34 is characterized in that, described the 1st fuse to the specific refractivity difference of described the 2nd fuse be 3% and more than.
36., it is characterized in that described the 1st fuse external diameter is D1 according to claim 34 or 35 described optical fiber, when the external diameter of described the 2nd fuse was D2, D1/D2=Da was 0.3～0.7.
37. an optical fiber is characterized in that, makes center unanimity separately in the one or both ends of the described optical fiber of claim 29 and single-mode fiber, covering external diameter 120～130 μ m dispersion-shifted fibers or the Aeff of welding covering external diameter 120～130 μ m are 20 μ m 2And any one optical fiber in the above optical fiber, and to this weld portion enforcement heat treated.
38. a light signal processing device is characterized in that, described light signal processing device has adopted the described optical fiber of described claim 1.
39. an optical fiber is characterized in that n 2/ Aeff is a nonlinear constant, and a is a loss, and λ is a wavelength, when L is the length of optical fiber, λ in the scope of 1500nm～1600nm, the ((n of 2 π/λ) 2The value of/Aeff) [1-exp (aL)]/a be 1/W and more than, the absolute value of the wavelength dispersion at wavelength 1550nm place is 30ps/nm/km and following, the bending loss of the diameter 5mm at wavelength 1550nm place is 0.5dB/m and following.
40. according to the described optical fiber of claim 39, it is characterized in that, λ in the scope of 1500nm～1600nm, the ((n of 2 π/λ) 2/ Aeff) be 8～17/W/km, L is 0.5～30km, loss a is 0.2～0.6dB/km.
41. an optical fiber is characterized in that, λ in the scope of 1500nm～1600nm, the ((n of 2 π/λ) 2/ Aeff) be 17～27/W/km, L is 0.01～10km, loss a is 0.4～2dB/km.
42. a light signal processing device is characterized in that, described light signal processing device has adopted any described optical fiber in the described claim 39～41.
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EP3657223B1 (en) * 2017-07-18 2023-10-18 Fujikura Ltd. Optical fiber and method for producing same
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Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07261048A (en) * 1994-03-23 1995-10-13 Sumitomo Electric Ind Ltd Dispersion compensating fiber
JP3337954B2 (en) * 1997-09-17 2002-10-28 株式会社フジクラ Dispersion compensating optical fiber
TWI226464B (en) * 2000-11-13 2005-01-11 Sumitomo Electric Industries Optical fiber, non-linear optical fiber, optical amplifier using the same optical fiber, wavelength converter and optical fiber manufacture method
JP2002162529A (en) * 2000-11-28 2002-06-07 Furukawa Electric Co Ltd:The Optical fiber, and optical communication system using the optical fiber
CN1264031C (en) * 2001-10-04 2006-07-12 古河电气工业株式会社 Nonlinear dispersion displacement optical fibre, optical signal treater and wavelength converter

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* Cited by examiner, † Cited by third party
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CN103443701A (en) * 2011-03-04 2013-12-11 古河电气工业株式会社 Optical amplifier, optical amplifying system, wavelength converter, optical amplification method, and optical communication system
US9270076B2 (en) 2011-03-04 2016-02-23 Furukawa Electric Co., Ltd. Optical amplifier, optical amplifying system, wavelength converter, optical amplification method, and optical communication system
CN103443701B (en) * 2011-03-04 2017-04-12 古河电气工业株式会社 Optical parameter amplifier, optical amplifying system, wavelength converter, optical amplification method, and optical communication system
CN102844688A (en) * 2011-04-18 2012-12-26 住友电气工业株式会社 Plastic-clad optical fiber core and optical fiber cable
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CN110346866B (en) * 2019-06-12 2020-08-25 烽火通信科技股份有限公司 Panda type polarization maintaining optical fiber

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