CN103076655A - Adjustable optical attenuator wavelength division multiplexer - Google Patents
Adjustable optical attenuator wavelength division multiplexer Download PDFInfo
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- CN103076655A CN103076655A CN2013100179604A CN201310017960A CN103076655A CN 103076655 A CN103076655 A CN 103076655A CN 2013100179604 A CN2013100179604 A CN 2013100179604A CN 201310017960 A CN201310017960 A CN 201310017960A CN 103076655 A CN103076655 A CN 103076655A
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Abstract
The invention provides an adjustable optical attenuator wavelength division multiplexer, which comprises an adjustable optical attenuator and wavelength division multiplexers, wherein the adjustable optical attenuator is provided with one or two input ports and an output port; and the quantity of the wavelength division multiplexers is equal to that of the input ports of the adjustable optical attenuator, each wavelength division multiplexer corresponds to one input port, each wavelength division multiplexer is provided with a plurality of channel input ports and a channel output port, and each channel output port is used for outputting signals to the input port corresponding to each wavelength division multiplexer. The adjustable optical attenuator wavelength division multiplexer provided by the invention is simple in structure and low in packaging difficulty.
Description
Technical field
The present invention relates to a kind of optical device for optical fiber telecommunications system, specifically, relate to a kind of variable optical attenuation wavelength division multiplexer.
Background technology
The optical signal transmission speed of modern optical fiber telecommunications system is more and more faster, and the capacity of system is also increasing, and this depends on the application of Erbium-Doped Fiber Amplifier (EDFA) (EDFA) and dense wave division multipurpose (DWDM) technology.But, because the signal light power unevenness of optical signal transmitter emission and the gain spectral unevenness of Erbium-Doped Fiber Amplifier (EDFA), so that the some different wave length signals in the dense wavelength division multiplexing system are through behind the Erbium-Doped Fiber Amplifier (EDFA), corresponding gain is inconsistent, and along with a plurality of Erbium-Doped Fiber Amplifier (EDFA) cascades in the long haul communications systems are used, so that this gain unevenness constantly accumulates, cause the power of different channels extremely inhomogeneous, cause the dynamic unbalance of optical fiber telecommunications system.
In addition, in optical fiber telecommunications system, when the number of channel increase and decrease of light transmission or certain channel power change, also can cause other channel power saltus step, the optical power value that each channel of receiver is received and the signal to noise ratio (S/N ratio) of light signal are also just different.This lack of uniformity is very harmful to the transmission performance of whole optical fiber telecommunications system, tends to make between each road signal crosstalk, and makes the bit error rate of some wavelength channel be higher than designated value.If unbalanced performance number is too high, can cause the transmission generation nonlinear effect of light signal in optical fiber, and the optical power value that causes receiver to receive surpasses the maximum dynamic range of receiver.If unbalanced performance number is excessively low, the optical power value that can cause receiver to receive is lower than the sensitivity of receiver, then causes receiver not receive light signal.
Therefore, people use all channel adjustable optical attenuator that the signal light power of each channel is carried out dynamic adjustments that the signal of a plurality of channels is carried out optical power adjustment, and the most common device is planar waveguide-type variable attenuator array.And for example, notification number is that the Chinese utility model patent of CN2596384Y also discloses the innovation and creation of a kind of " high reliability liquid crystal array variable attenuator " by name, this variable attenuator has a plurality of light input end mouths and a plurality of optical output port, between each light input end mouth and an optical output port decay passage is set, each bar decay passage has the polarizer, liquid crystal light polarization modulating device, collimating apparatus etc.After the signal of each channel carried out attenuation processing through a decay passage, from an optical output port outgoing, so the signal of a plurality of channels of this variable attenuator output was respectively from a plurality of output port outputs.
Because the signal of a plurality of channels need to transmit in an optical fiber after adjustable optical attenuator output, therefore a wavelength division multiplexer need to be set at the output terminal of adjustable optical attenuator, on signal multiplexing to an optical fiber with many channels.Like this, just a wavelength division multiplexer need to be set at the output terminal of adjustable optical attenuator, and wavelength division multiplexer have a plurality of input ports, the signal of an output port output of each input port reception adjustable optical attenuator.Therefore, will there be the connectivity problem between a plurality of input ports of a plurality of output ports of adjustable optical attenuator and wavelength division multiplexer in the variable optical attenuation wavelength division multiplexer of using adjustable optical attenuator and wavelength division multiplexer formation.Because the output port quantity of adjustable optical attenuator is more, the input port quantity of wavelength division multiplexer is also more, being connected, aiming between a plurality of output ports of realizing adjustable optical attenuator and a plurality of input ports of wavelength division multiplexer is very difficult, cause device architecture complicated, and bring very large difficulty for the encapsulation of device.
Summary of the invention
Fundamental purpose of the present invention provides a kind of variable optical attenuation wavelength division multiplexer of simple in structure and easy encapsulation.
In order to realize above-mentioned fundamental purpose, variable optical attenuation wavelength division multiplexer device provided by the invention comprises adjustable optical attenuator and wavelength division multiplexer, adjustable optical attenuator has one or two input ports, and be provided with an output port, the quantity of wavelength division multiplexer equates with the quantity of the input port of adjustable optical attenuator, and each wavelength division multiplexer is corresponding with an input port, each wavelength division multiplexer has a plurality of channel input ports and a channel output port, and this channel output port is to input port output signal corresponding to wavelength division multiplexer.
By such scheme as seen, after the signal of a plurality of channels enters the variable optical attenuation wavelength division multiplexer, at first incide in the wavelength division multiplexer, by wavelength division multiplexer the signal of a plurality of channels is carried out multiplexingly, output to the input port of adjustable optical attenuator from the channel output port of wavelength division multiplexer.Because the signal of a plurality of channels will be through exporting from a channel output port behind the wavelength division multiplexer, adjustable optical attenuator only arranges the signal that or two input ports namely can receive a plurality of channels, and export the signal of a plurality of channels by an output port, there is not the problem that a plurality of ports of adjustable optical attenuator are connected with a plurality of ports of wavelength division multiplexer in device like this, variable optical attenuation wavelength division multiplexer simple in structure, and encapsulation difficulty also reduces greatly.
A preferred scheme is, adjustable optical attenuator is all channel adjustable optical attenuator, and the quantity of the input port of all channel adjustable optical attenuator is one, and wavelength division multiplexer is all channel dense wave division multiplexer.
This shows, can be with signal multiplexing to a channel output port output of all channels by all channel dense wave division multiplexer, wavelength division multiplexer only uses a port to be connected with a port of adjustable optical attenuator and gets final product, and the encapsulation of device is simple.
Further scheme is, the all channel adjustable optical attenuator has the first Dispersive Devices that is positioned at the input port exit end, the exit end of the first Dispersive Devices is provided with the first condenser lens, the focal plane of the first condenser lens is provided with the fading channel adjustment module, the fading channel adjustment module has a plurality of regulons, the exit end of fading channel adjustment module is provided with the second condenser lens, and the focal plane of the second condenser lens is provided with the second Dispersive Devices, and output port is positioned at the exit end of the second Dispersive Devices.
As seen, the all channel adjustable optical attenuator separates by the light signal of the first Dispersive Devices with different channels, and the light signal that makes each channel incides in the regulon of fading channel adjustment module and carries out attenuation processing, light signal after the attenuation processing is again through exporting behind the second Dispersive Devices, therefore all channel adjustable optical attenuator only comprises an input port and an output port, makes the encapsulation of device more simple.
Another preferred scheme is, adjustable optical attenuator is staggered adjustable optical attenuator, the quantity of its input port is two, respectively strange channel input port and even channel input port, the quantity of wavelength division multiplexer is two, respectively corresponding to the strange channel dense wave division multiplexer of strange channel input port and corresponding to the even channel dense wave division multiplexer of even channel input port, and, strange channel input port by light isolation device to the first collimator output beam, idol channel input port is to the first port output beam of circulator, the second port of circulator is to the second collimating apparatus output beam, adjustable optical attenuator also comprises the 3rd birefringece crystal, be positioned at the exit end of first collimator and the exit end of the second collimating apparatus, the exit end of the 3rd birefringece crystal is provided with the 3rd Dispersive Devices, the exit end of the 3rd Dispersive Devices is provided with the 3rd condenser lens, one Liquid crystal module is arranged on the focal plane of the 3rd condenser lens, Liquid crystal module has and is arranged near the second liquid crystal array of the 3rd condenser lens one side and away from the catoptron of the 3rd condenser lens, and the second liquid crystal array has two groups of above liquid crystal cells.
By such scheme as seen, use strange channel dense wave division multiplexer and even channel dense wave division multiplexer with the signal multiplexing of the signal of a plurality of strange channels and a plurality of even channels and output to two input ports of staggered adjustable optical attenuator, undertaken exporting after the attenuation processing by the signal of adjustable optical attenuator to each channel.Therefore, adjustable optical attenuator only is connected with strange channel dense wave division multiplexer, even channel dense wave division multiplexer respectively by two ports, and the variable optical attenuation wavelength division multiplexer is simple in structure, and encapsulation easily, conveniently.
Description of drawings
Fig. 1 is the optical texture schematic diagram of variable optical attenuation wavelength division multiplexer the first embodiment of the present invention.
Fig. 2 is the optical texture schematic diagram of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the first embodiment of the present invention.
Fig. 3 is the structure enlarged diagram of grating, condenser lens and the Liquid crystal module of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the first embodiment of the present invention.
Fig. 4 is the structure enlarged diagram of the Liquid crystal module of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the first embodiment of the present invention.
Fig. 5 is the optical texture schematic diagram of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the second embodiment of the present invention.
The structure enlarged diagram of grating, condenser lens and the Liquid crystal module of adjustable optical attenuator among Fig. 6 variable optical attenuation wavelength division multiplexer the second embodiment of the present invention.
Fig. 7 is the structure enlarged diagram of the Liquid crystal module of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the second embodiment of the present invention.
Fig. 8 is the optical texture schematic diagram of variable optical attenuation wavelength division multiplexer the 3rd embodiment of the present invention.
Fig. 9 is the optical texture schematic diagram of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the 3rd embodiment of the present invention.
Figure 10 is the optical texture schematic diagram of a regulon of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the 3rd embodiment of the present invention.
Figure 11 is that the light beam of adjustable optical attenuator among variable optical attenuation wavelength division multiplexer the 3rd embodiment of the present invention is through the schematic diagram of regulon.
The invention will be further described below in conjunction with drawings and Examples.
Embodiment
Variable optical attenuation wavelength division multiplexer of the present invention can receive the signal of a plurality of channels, and after the luminous power of the signal of a plurality of channels regulated, from a port output.
The first embodiment:
Referring to Fig. 1, the variable optical attenuation wavelength division multiplexer of the present embodiment has strange channel dense wave division multiplexer 1, idol channel dense wave division multiplexer 2 and adjustable optical attenuator 10, adjustable optical attenuator 10 has two input ports, respectively strange channel input port 11 and even channel input port 12, strange channel dense wave division multiplexer 1 is corresponding with strange channel input port 11, signal to a plurality of strange channels of strange channel input port 11 outputs, idol channel dense wave division multiplexer 2 is corresponding with even channel input port 12, exports the signal of a plurality of even channels to even channel input port 12.
Strange channel dense wave division multiplexer 1 has a plurality of channel input ports 3, is used for receiving the signal of a plurality of strange channels, and the signal of a plurality of strange channels is closed light export from channel output port 4, exports in the strange channel input port 11 in the adjustable optical attenuator 10.Idol channel dense wave division multiplexer 2 has a plurality of channel input ports 5, is used for receiving the signal of a plurality of even channels, and the signal of a plurality of even channels is closed output from channel output port 6 behind the light, exports in the even channel input port 12 of adjustable optical attenuator 10.
After the signal of 10 pairs of strange channels of adjustable optical attenuator and the signal of even channel close light or carry out the adjusting of luminous power, from output port 49 outputs.The concrete structure of adjustable optical attenuator 10 as shown in Figure 2.
Referring to Fig. 2, two input ports of adjustable optical attenuator 10 are respectively strange channel input port 11, even channel input port 12, receive respectively the signal of strange channel and the signal of even channel.The signal of strange channel and the signal of even channel are the signals of the different wave length propagated in optical fiber telecommunications system, and the optical wavelength of the signal of each channel is not identical with the optical wavelength of the signal of other channels.For example, in the system of 50G hertz channel spacing, the difference on the frequency of two adjacent channels is the 50G hertz, channel number in this system is that the channel of odd number is strange channel, the frequency of its channel is the odd-multiple of 50G hertz, channel number is that the channel of even number is even channel in the system, and the frequency of its channel is the even-multiple of 50G hertz, and therefore strange channel and even channel are alternative arrangement.
The exit end of strange channel input port 11 is provided with circulator 13, circulator 13 is as a light isolation device, it has three ports, it is respectively the first port 14, the second port one 5 and the 3rd port one 6, can only be from 5 outgoing of the second port one from the light of the first port 14 incidents, can only be from 6 outgoing of the 3rd port one from the light of the second port one 5 incidents, and can not reversely transmit, guaranteeing can not be from 14 outgoing of the first port from the light of the second port one 5 incidents, avoid light through being back to the strange channel dense wave division multiplexer 1 of prime behind the adjustable optical attenuator, also just avoid backing system caused and crosstalk.And, be provided with collimating apparatus 17 at the second port one 5 of circulator 13.
Strange channel light beam L11 incides the first port 14 rear formation light beam L12 of circulator 13 from 5 outgoing of the second port one, light beam L12 is through forming light beam L13 after the collimating apparatus 17, light beam L13 includes orthogonal two components of polarization state, use arrow to represent to be parallel to the polarization state of paper direction among Fig. 2, the use round dot represents the polarization state perpendicular to the paper direction.
The exit end of idol channel input port 12 also is provided with circulator 23, circulator 23 also has three ports, be respectively the first port 24, the second port 25, the 3rd port 26, light can only be according to from the first port 24 to second ports 25, from the transmission of the direction of the second port 25 to the 3rd ports 26 in circulator 23.The exit end of the second port 25 also is provided with collimating apparatus 27.
After inciding the first port 24 of circulator 23 from the light beam L31 of even channel input port 12 outgoing, form light beam L32 from 25 outgoing of the second port, light beam L32 is through forming light beam L33 after the collimating apparatus 27, light beam L33 also includes orthogonal two components of polarization state.
Be provided with a birefringece crystal 18 at collimating apparatus 17,27 exit end, its plane of incidence can incide the plane of incidence of birefringece crystal 18 over against collimating apparatus 17,27 exit ports from light beam L13, the L33 of collimating apparatus 17,27 outgoing.After light beam L13 incides birefringece crystal 18, will form the orthogonal two light beams L14 of polarization state, L15, light beam L14 is ordinary light, and the polarization direction is parallel to paper, and light beam L15 is extraordinary ray, and the polarization direction is perpendicular to paper.For the polarization state that makes the polarized light that incides birefringece crystal 18 rear level systems is identical, be provided with half-wave plate 19 in the light path of light beam L15, and half-wave plate 19 is arranged on the exit facet of birefringece crystal 18.Like this, light beam L15 is through forming light beam L17 behind the half-wave plate 19, the polarization direction of light beam L17 is compared with the polarization direction of light beam L15, and 90 ° deflection has occured, its polarization direction is parallel to paper, and is namely identical with the polarization direction of light beam L16 after light beam L14 passes birefringece crystal 18.
Light beam L33 also forms the orthogonal two light beams L34 of polarization state, L35 after inciding birefringece crystal 18, the polarization direction of light beam L34 is parallel to paper, form light beam L36 after birefringece crystal 18 outgoing, the polarization direction of light beam L36 is identical with the polarization direction of light beam L34.The polarization direction of light beam L35 is perpendicular to paper, be provided with half-wave plate 20 in the light path of light beam L35, and half-wave plate 20 is positioned on the exit facet of birefringece crystal 18.Light beam L35 is through forming light beam L37 behind the half-wave plate 20, and 90 ° deflection occurs in the polarization direction, so the polarization direction of light beam L37 is identical with the polarization direction of light beam L36.
Exit end at birefringece crystal 18 is provided with prism beam expander group 30, and it comprises two prism beam expanders 31,32, and light beam L16, L17, L36, L37 are increased through hot spot behind the prism beam expander 31,32 respectively, and incide in the grating 33.Prism beam expander 31,32 is as the unidirectional extended device of the light beam of the present embodiment, will enlarge from the hot spot of the light beam of birefringece crystal 18 outgoing, but the hot spot of the light beam of opposite direction incident can not be enlarged.
After light beam collection L18, L19, L38, L39 incide the condenser lens 34 that is positioned at grating 33 exit ends, the direction of propagation changes, and form respectively light beam collection L20, L21, L40, L41, and the polarization state of light beam collection L20, L21, L40, L41 is identical, all is to be parallel to paper.
Be provided with Liquid crystal module 36 on the focal plane of condenser lens 34, as shown in Figures 3 and 4, Liquid crystal module 36 is comprised of liquid crystal array 37, birefringece crystal angle of wedge sheet 38 and catoptron 39, liquid crystal array 37 has many group liquid crystal cells 41,42,43 etc., it is positioned at the side near condenser lens 34, and on the focal plane of condenser lens 34, catoptron 39 is positioned at the side away from condenser lens 34, and birefringece crystal angle of wedge sheet 38 is between liquid crystal array 37 and catoptron 39.
Be provided with a large amount of liquid crystal molecules in each liquid crystal cells, load the orientation that certain voltage will change liquid crystal molecule to liquid crystal cells, linearly polarized photon passes the liquid crystal cells under the different conditions, the rotation of certain angle will occur in polarization state: when loading a specified high voltage to liquid crystal cells, after linearly polarized photon passes liquid crystal cells, polarization state can not deflect, load one during less than specified high voltage to liquid crystal cells, after linearly polarized photon passes liquid crystal cells, the deflection of certain angle will occur in its polarization state, the angle of deflection is relevant with the voltage of loading, therefore can change the polarization state of the linearly polarized photon that passes this liquid crystal cells to the voltage on the liquid crystal cells by controlled loading.
Because light beam L16, L17, L36, L37 are through forming different light beam collection L18, L19, L38, the L39 of scattering angle behind the grating 33, the light beam of identical wavelength is through inciding on the same liquid crystal cells of liquid crystal array 37 behind the condenser lens 34 among these light beam collection L18, L19, L38, the L39, but light beam concentrates the light beam of L18, L19, wavelength that L38, L39 are different will incide in the different liquid crystal cells of liquid crystal array 37.For example, the wavelength of light beam L181 is identical with the wavelength of light beam L191, forms respectively light beam L201, L211 through behind the condenser lens 34, and light beam L201, L211 incide in the same liquid crystal cells of liquid crystal array 37.But the wavelength of light beam L181 is different from the wavelength of light beam L182, so light beam L181, L182 incide in the different liquid crystal cells of liquid crystal array 37 through behind the condenser lens 34.
Because it is not identical with wavelength from the light beam of even channel outgoing from the wavelength of the light beam of strange channel outgoing, therefore the light beam from strange channel outgoing is focused on the different liquid crystal cells of liquid crystal array 37 from the light beam of even channel outgoing, and also be focused on the different liquid crystal cells of liquid crystal array 37 through the different wave length bundle that is divided into behind the grating 33 from the light beam of strange channel outgoing, also be focused on the different liquid crystal cells of liquid crystal array 37 through the different wave length bundle that is divided into behind the grating 33 from the light beam of even channel outgoing.
Different liquid crystal cells to liquid crystal array 37 load different magnitudes of voltage, can change the polarization state of different light beams.For example, at liquid crystal cells 41, during the specified high voltage of 42 loadings, such as 8 volts, light beam L20 passes liquid crystal cells 41,42 rear polarizer attitudes do not deflect, it incides follows refraction law behind the birefringece crystal angle of wedge sheet 38 and reflects, formation light beam L22 also incides on the reflecting surface of catoptron 39, light beam through catoptron 39 reflections reflects along a reflection paths, form light beam L23, form light beam L24 and pass through successively liquid crystal cells 42 behind the light beam L23 process birefringece crystal angle of wedge sheet 38, condenser lens 34, grating 33, prism beam expander group 30, birefringece crystal 18, collimating apparatus 17 incides the second port one 5 of circulator 13, and from the 3rd port one 6 outgoing of circulator 13.
If load lower voltage to liquid crystal cells 41,43, can change the polarization state of passing liquid crystal cells 41,43 linearly polarized photon.For example, liquid crystal cells 41 is loaded lower voltage, after light beam L20 passed liquid crystal cells 42,90 ° deflection just occured in the polarization direction, and therefore the light polarization of process liquid crystal cells 41 is perpendicular to paper.This light beam incides not to be followed refraction law behind the birefringece crystal angle of wedge sheet 38 and reflects, form deflecting light beams L25 and incide catoptron 39, form folded light beam L26, light beam L26 incides birefringece crystal angle of wedge sheet 38 rear formation light beam L27 and passes liquid crystal cells 43, the again deflection of its polarization state, travel path is near the lower end of adjustable optical attenuator, therefore light beam L27 will pass through condenser lens 34 successively, grating 33, prism beam expander group 30, birefringece crystal 18, collimating apparatus 27 incides the second port 25 of circulator 23, from the 3rd port 26 outgoing of circulator 23.
As seen, at the different voltage of different liquid crystal cells loadings of liquid crystal array 37, from the light beam of strange channel incident, part is from the 3rd port one 6 outgoing of circulator 13, and part is from the 3rd port 26 outgoing of circulator 23.If the 3rd port 26 of circulator 23 is set as the output port of adjustable optical attenuator, namely the output port among Fig. 1 49 can partly or entirely be exported from output port 49 from the light beam of strange channel input port 11 incidents like this.As seen, need the signal of a certain strange channel from output port 49 outputs, can load lower voltage by liquid crystal cells corresponding in liquid crystal array 37 and realize.
Also be to incide on the different liquid crystal cells of liquid crystal array 37 from the light beam of even channel input port 12 outgoing, by loading different voltage to different liquid crystal cells, also can make the signal section ground of even channel or all export from output port 49.
Therefore, in the liquid crystal array 37 the liquid crystal cells that passes of the light beam of odd channel load and be lower than specified high voltage, change the polarization state of the light beam of strange channel outgoing fully, make light beam from strange channel outgoing fully from output port 49 outputs.And the liquid crystal cells that the light beam of all even channels passes in the liquid crystal array 37 loads specified high voltage, does not deflect through liquid crystal cells rear polarizer attitude from the light beam of even channel outgoing, returns along input path fully, also just exports from output port 49.Owing to all exporting from output port 49 with the light beam from even channel outgoing from the light beam of strange channel outgoing, therefore having realized that the signal of strange channel and the signal of even channel close ripple.
If need to use the signal of the strange channel of adjustable optical attenuator dynamic adjustments and the signal light power of even channel, the liquid crystal cells that then light beam of the strange channel of part passes in the liquid crystal array 37 loads and is lower than specified high voltage, the liquid crystal cells that the light beam of the strange channel of another part passes in the liquid crystal array 37 loads specified high voltage, partly change the polarization state of the light beam of strange channel outgoing, make from the light beam part of strange channel dense wave division multiplexer 1 outgoing and export from output port 49, another part is back to circulator 13, so namely realizes the signal light power decay of different strange channels.
In like manner, the signal light power of a plurality of even channels also can realize decay by identical method, also can load different magnitudes of voltage by the liquid crystal cells to varying number and change from the luminous power of the signal of output port 49 outgoing.
During practical application, often only need to use the 3rd port 26 output signals of circulator 23, then circulator 13 can be replaced to a common optoisolator, can pass optoisolator from the light beam of strange channel input port 11 outgoing and incide collimating apparatus 17, incide strange channel input port 11 but can not pass optoisolator from the light beam that collimating apparatus 17 is returned.
The second embodiment:
The variable optical attenuation wavelength division multiplexer of the present embodiment has an adjustable optical attenuator and strange channel dense wave division multiplexer, even channel dense wave division multiplexer, adjustable optical attenuator has two input ports, be respectively strange channel input port and even channel input port, receive respectively the signal of the strange channel of strange channel dense wave division multiplexer, the output of even channel dense wave division multiplexer, the signal of even channel.
Referring to Fig. 5, the exit end of the strange channel input port 51 of the adjustable optical attenuator of the present embodiment is provided with optoisolator 53, and the exit end of optoisolator 53 is provided with collimating apparatus 57.Behind the light beam L51 process optoisolator of strange channel input port 51 outgoing, form light beam L52, light beam L52 is incident to collimating apparatus 57, incide the birefringece crystal 58 and form the orthogonal two light beams L54 of polarization state, L55 from the light beam L53 of collimating apparatus 57 outgoing, light beam L54 is ordinary light, its polarization state is parallel to paper, light beam L55 is extraordinary ray, and its polarization state is perpendicular to paper.
Incide the first port 64 of circulator 63 from the light beam L61 of even channel input port 52 outgoing, light beam L62 is from the second port 65 outgoing of circulator 63 and incide the collimating apparatus 67, incide the orthogonal two light beams L64 of birefringece crystal 58 rear formation polarization states, L65 from the light beam L63 of collimating apparatus 67 outgoing, wherein the polarization state of light beam L64 is parallel to paper, and the polarization state of light beam L65 is perpendicular to paper.
Exit facet at birefringece crystal 58 is provided with a half-wave plate 59, and half-wave plate 59 is positioned on the light path of light beam L55 and light beam L64, is used for changing the polarization state of light beam L55 and light beam L64.
Light beam L54 passes birefringece crystal 58 rear formation light beam L56, polarization state can not change, and after light beam L55 passed birefringece crystal 58 and half-wave plate 59,90 ° deflection occured polarization state, and form light beam L57, so the polarization state of light beam L56 is parallel with the polarization direction of light beam L57.
Light beam L64 passes birefringece crystal 58 and half-wave plate 59 rear formation light beam L66, and the polarization direction of light beam L66 is compared with the polarization direction of light beam L64, and 90 ° deflection has occured.It is constant that light beam L65 passes birefringece crystal 58 rear polarizer directions, and form light beam L67.Therefore the polarization direction of light beam L66 is parallel with the polarization direction of light beam L67.
Light beam L56, L57 incide that the reflecting surface 71 of polarization spectro splicer spare (PBS) 70 is rear to be formed respectively light beam L58, L59 and reflex on the transparent surface 72, light beam L66 closes light formation light beam L70 with light beam L58 after inciding the transparent surface 72 of polarization spectro splicer spare 70, so light beam L70 includes orthogonal two components of polarization state.Light beam L67 incides behind the transparent surface 72 and light beam L59 closes light, form light beam L71, so light beam L71 includes orthogonal two components of polarization state.
Light beam L70, L71 are through being arranged on the prism beam expander group 73 of polarization spectro splicer spare 70 exit ends, and prism beam expander group 73 comprises two as the prism beam expander 74,75 of the unidirectional extended device of the present embodiment light beam.Certainly, during practical application, can determine according to actual operating position the quantity of employed prism beam expander.Spot diameter expanded after light beam L70, the L71 process prism beam expander group 73, and incide formation light beam collection L72, L73 in the grating 76, each light beam collection L72, L73 all comprise the different multiple light beams of scattering angle.Light beam collection L72, L73 pass that condenser lens 77 is rear to form respectively light beam collection L74, L75, and incide in the Liquid crystal module 78.
Shown in Figure 6 is the vertical view of grating 76, condenser lens 77 and Liquid crystal module 78, and light beam L70 comprises light beam L721, L722, the L723 that scattering angle difference and wavelength are not identical through the light beam collection L72 that forms behind the grating 76.Light beam L721, L722, L723 form respectively light beam L741, L742, L743 through behind the condenser lens 77, and incide respectively in the different liquid crystal cells of the liquid crystal array 80 of Liquid crystal module 78.
Certainly, light beam L71 also comprises multi beam scattering angle difference and the different light beam of wavelength through the light beam collection L73 that forms behind the grating 76, and these light beams are through also inciding respectively behind condenser lenses 77 in the different liquid crystal cells of liquid crystal array 80.And the light beam of identical wavelength will incide in the same liquid crystal cells of liquid crystal array 80 among light beam collection L72 and the light beam collection L73.
Referring to Fig. 7, the Liquid crystal module 78 of the present embodiment is comprised of liquid crystal array 80 and catoptron 79, and liquid crystal array 80 comprises many group liquid crystal cells 81,82 etc., and is positioned at the side near condenser lens 77, and catoptron 79 is positioned at the side away from condenser lens 77.
Because different with the wavelength from the light beam of even channel input port 52 outgoing from the wavelength of the light beam of strange channel input port 51 outgoing, will incide on the different liquid crystal cells of liquid crystal array 80 through the light beam of scattering formation behind the grating 76.
Load different magnitudes of voltage by liquid crystal cells different in liquid crystal array 80, can change the polarization state of the linearly polarized photon that passes this liquid crystal cells.For example, load specified high voltage to liquid crystal cells 81, voltage such as 8 volts, light beam L80 passes liquid crystal cells 81 rear polarizer directions and can not change, the light beam L81 polarization direction that forms is parallel to paper, behind the reflecting surface of catoptron 79, again pass liquid crystal cells 81 and return along the light path of incident, namely successively through being incident to optoisolator 53 after condenser lens 77, grating 76, prism beam expander group 73, polarization spectro splicer spare 70, birefringece crystal 58 and the collimating apparatus 57, be consumed.
Load lower voltage to liquid crystal cells 82, light beam L82 passes 45 ° of liquid crystal cells 82 rear polarizer attitude deflections, the light beam L83 that forms returns in the liquid crystal cells 82 through the reflecting surface back reflection of catoptron 79,45 ° deflection occurs in the polarization state of light beam again, this moment light beam polarization state perpendicular to paper, this light beam after liquid crystal cells 82 outgoing successively through condenser lens 77, light beam 76, prism beam expander group 73 and be incident on the transparent surface 72 of polarization spectro splicer spare 70.Because the light beam that polarization state is parallel to paper is reflected onto on the reflecting surface 71, and polarization state will directly be passed transparent surface 71 perpendicular to the light beam of paper, be incident in the birefringece crystal 58.Therefore, the light beam that polarization state changes will can not be back in the collimating apparatus of its incident according to original path, but turn back in another collimating apparatus.For example, original light beam L51 process collimating apparatus 57 from strange channel input port 51 outgoing, if the polarization state of this light beam changes, then after reflecting through catoptron 79, to pass the transparent surface 72 of polarization spectro splicer spare 70 and incide in the collimating apparatus 67, incide at last the second port 65 of circulator 63, and from the 3rd port 66 outgoing of circulator 63.
As seen, Liquid crystal module 78 to condenser lens 77, and is realized the beam reflection of incident to the change of the polarization state of linearly polarized photon or is not changed by load different voltage to different liquid crystal cells.
If the 3rd port 66 of circulator 63 is set as the output port of adjustable optical attenuator, then can be partially or completely from output port output from the light beam of strange channel input port 51 outgoing, this depends on the magnitude of voltage of liquid crystal cells on-load voltages different in the liquid crystal array 80.In like manner, also can partially or completely export from the output port of adjustable optical attenuator from the light beam of even channel input port 52 outgoing.
Like this, all load lower voltage from the liquid crystal cells that the light beam of strange channel input port 51 outgoing passes in liquid crystal array, namely change all from the polarization state of the light beam of strange channel input port 51 outgoing, all will be exported from output port from the light beam of strange channel input port 51 outgoing like this.And, all liquid crystal cells that pass from the light beam of even channel input port 52 outgoing load specified high voltage in the liquid crystal array, just do not change the polarization state of arbitrary light beam from even channel input port 52 outgoing yet, from the light beam of even channel input port 52 outgoing also just fully from output port output, realize the signal of strange channel and even channel signal close light.
Regulate the luminous power of the signal of the signal of strange channel and even channel if need to use adjustable optical attenuator, the voltage that then 80 different liquid crystal cells load in the adjustable liquid crystal display array, can make from the beam section of strange channel input port 51 outgoing and be back to optoisolator 53, part is from the output port outgoing, and make from the beam section of even channel input port 52 outgoing and be back to optoisolator 53, part is from the output port outgoing, and this can realize by the quantity that adjusting is loaded the liquid crystal cells of specified high voltage.
The 3rd embodiment:
Referring to Fig. 8, the present embodiment has dense wave division multiplexer 91 and adjustable optical attenuator 100, and wherein adjustable optical attenuator 100 is all channel adjustable optical attenuator, namely can carry out attenuation processing to the signal of all channels.And adjustable optical attenuator 100 has an input port 101 and an output port 110.
Dense wave division multiplexer 91 is all channel dense wave division multiplexer, is arranged on the front end of adjustable optical attenuator 100, and it has a plurality of channel input ports 92, receives respectively the signal of a plurality of channels.And dense wave division multiplexer 91 also is provided with a channel output port 93, exports the input port 101 of adjustable optical attenuator 100 behind the signal multiplexing with a plurality of channels to.
Referring to Fig. 9, input port 101 exit ends of adjustable optical attenuator 100 are provided with collimating apparatus 102, the exit end of collimating apparatus 102 is provided with the grating 103 as Dispersive Devices, the exit end of grating 103 is provided with condenser lens 104, the focal plane of condenser lens 104 is provided with fading channel adjustment module 105, is provided with a plurality of regulons 106 in the fading channel adjustment module 105.Exit end in fading channel adjustment module 105 is provided with condenser lens 107, be provided with grating 108 in the focal plane of condenser lens 107, the exit end of grating 108 is provided with collimating apparatus 109, and the output port 110 of adjustable optical attenuator 100 is arranged on the exit end of collimating apparatus 109.
Be the light beam that comprises the signal of a plurality of channels from the light beam L101 of input port 101 outgoing, light beam L101 is through forming light beam L102 and inciding on the grating 103 after the collimating apparatus 102, light beam L102 will form the different light beam of scattering angle through behind the grating 103, such as light beam L103, L104 etc., and the wavelength of the light beam of different scattering angles is not identical.
After light beam L103, L104 etc. incide condenser lens 104, the direction of propagation changes, and formation light beam L105, L106 etc. incide in the fading channel adjustment module 105, the different wave length bundle will incide in the different regulon 106 of Attenuation adjustable module 105, each regulon 106 can be considered as a decay passage, is used for the signal of a channel is carried out attenuation processing.
Referring to Figure 10, the birefringece crystal 113 that regulon 106 has birefringece crystal 111, is positioned at the liquid crystal array 112 of birefringece crystal 111 exit ends and is positioned at liquid crystal array 112 exit ends, wherein liquid crystal array 112 has two groups of liquid crystal cells 114,115.
As the light beam L121 that incides regulon comprises orthogonal two components of polarization state, light beam L121 will form the orthogonal light beam L122 of polarization state and light beam L123 after inciding birefringece crystal 111, the polarization direction of light beam L122 is perpendicular to paper, and the polarization direction of light beam L133 is parallel to paper.Light beam L122, L123 form respectively light beam L124, L125 after birefringece crystal 111 outgoing, and incide respectively in the liquid crystal cells 114,115.If load specified high voltage to liquid crystal cells 114,115, then the polarization direction of light beam L124, L125 does not change.Light beam L124, L125 incide birefringece crystal 113 rear light beam L126, the L127 of forming respectively, and close light formation light beam L129 outgoing in birefringece crystal 113.
If load lower voltage to liquid crystal cells 114,115, can change the polarization state of passing liquid crystal cells 114,115 linearly polarized photon, as shown in figure 11, be divided into the orthogonal two light beams L132 of polarization state, L133 after inciding birefringece crystal 111 such as light beam L131, light beam L132, L133 form respectively light beam L134, L135 after birefringece crystal 111 outgoing, and pass respectively liquid crystal cells 114,115.Owing to loading lower voltage to liquid crystal cells 114,115, therefore light beam L134, L135 pass liquid crystal cells 114,90 ° deflection occurs 115 rear polarizer attitudes, two light beams incide birefringece crystal 113 rear form respectively light beam L136, L137 and close light form light beam L139 outgoing.
Contrast Figure 10 and Figure 11 as seen, the outgoing position of light beam L129 is not identical with the outgoing position of light beam L139, so can the luminous power consumers be set to sponge the luminous power of light beam L139 with respect to the position of light beam L139 outgoing at birefringece crystal 113.Like this, by the luminous power that can regulate the signal that passes each regulon 106 to the different voltage of liquid crystal cells loading, thereby realization is to the adjusting of the signal light power of different channels.
Review Fig. 9, the signal of a plurality of channels is through forming light beam L107, L108 etc. behind the different regulons 106, and incide condenser lens 107 rear formation light beam L109, L110 etc., multiple light beams L109, L110 incide grating 108 rear formation light beam L111, light beam L111 includes the signal of a plurality of channels, and formation light beam L112 incides output port 110 after collimating apparatus 109.
Certainly, adjustable optical attenuator 100 can also use other structures to realize, be that the utility model of CN2583888Y also discloses a kind of adjustable optical attenuator based on grating array such as notification number, this optical attenuator also has an input port and an output port, also can realize the luminous power of the signal of a plurality of channels is regulated.In addition, adjustable optical attenuator can also be based on the attenuator that microelectromechanical-systems technology, silica-based liquid crystal technology, digit optical treatment technology or other technologies make up, and one of them typical example is 1 * 1 wavelength blocking device (wavelength blocker).
Because adjustable optical attenuator only has one or two input port, it is very convenient with being connected of dense wave division multiplexer, and the assembling of device is also just comparatively simple.
Certainly, above-described embodiment only is the preferred embodiment of the invention, also more change can be arranged during practical application, for example in the situation of the volume of not considering adjustable optical attenuator, prism beam expander can be set; Perhaps, use dispersing prism to substitute grating as Dispersive Devices; Or dense wave division multiplexer can be to use based on the device of deielectric-coating filter technologies or the grating of waveguide array etc., and such change can't affect enforcement of the present invention.
It is emphasized that at last to the invention is not restricted to above-mentioned embodiment, also should be included in the protection domain of claim of the present invention such as the change of dense wave division multiplexer structure, the variations such as change of all channel adjustable attenuator structure.
Claims (10)
1. the variable optical attenuation wavelength division multiplexer is characterized in that: comprise
Adjustable optical attenuator has one or two input ports, and is provided with an output port;
Wavelength division multiplexer, the quantity of described wavelength division multiplexer equates with the quantity of described input port, and each described wavelength division multiplexer is corresponding with a described input port, each described wavelength division multiplexer has a plurality of channel input ports and a channel output port, and described channel output port is to described input port output signal corresponding to described wavelength division multiplexer.
2. variable optical attenuation wavelength division multiplexer according to claim 1 is characterized in that:
Described adjustable optical attenuator is all channel adjustable optical attenuator, and the quantity of the described input port of described all channel adjustable optical attenuator is one, and described wavelength division multiplexer is all channel dense wave division multiplexer.
3. variable optical attenuation wavelength division multiplexer according to claim 2 is characterized in that:
Described all channel adjustable optical attenuator has the first Dispersive Devices that is positioned at described input port exit end, the exit end of described the first Dispersive Devices is provided with the first condenser lens, the focal plane of described the first condenser lens is provided with the fading channel adjustment module, described fading channel adjustment module has a plurality of regulons, the exit end of described fading channel adjustment module is provided with the second condenser lens, the focal plane of described the second condenser lens is provided with the second Dispersive Devices, and described output port is positioned at the exit end of described the second Dispersive Devices.
4. variable optical attenuation wavelength division multiplexer according to claim 3 is characterized in that:
Each described regulon has the first birefringece crystal, and the exit end of described the first birefringece crystal is provided with the first liquid crystal array, and the exit end of described the first liquid crystal array is provided with the second birefringece crystal.
5. variable optical attenuation wavelength division multiplexer according to claim 1 is characterized in that:
Described adjustable optical attenuator is staggered adjustable optical attenuator, and the quantity of the described input port of described staggered adjustable optical attenuator is two, and two described input ports are respectively strange channel input port and even channel input port;
The quantity of described wavelength division multiplexer is two, is respectively corresponding to the strange channel dense wave division multiplexer of described strange channel input port and corresponding to the even channel dense wave division multiplexer of described even channel input port;
To the first collimator output beam, described even channel input port is to the first port output beam of circulator by light isolation device for described strange channel input port, and the second port of described circulator is to the second collimating apparatus output beam;
Described staggered adjustable optical attenuator also is provided with the 3rd birefringece crystal, described the 3rd birefringece crystal is positioned at the exit end of described first collimator and the exit end of described the second collimating apparatus, the exit end of described the 3rd birefringece crystal is provided with the 3rd Dispersive Devices, the exit end of described the 3rd Dispersive Devices is provided with the 3rd condenser lens, one Liquid crystal module is arranged on the focal plane of described the 3rd condenser lens, described Liquid crystal module has and is arranged near the second liquid crystal array of described the 3rd condenser lens one side and away from the catoptron of described the 3rd condenser lens, and described the second liquid crystal array has two groups of above liquid crystal cells.
6. variable optical attenuation wavelength division multiplexer according to claim 5 is characterized in that:
Be provided with birefringece crystal angle of wedge sheet between described the second liquid crystal array and the described catoptron.
7. it is characterized in that according to claim 5 or 6 described variable optical attenuation wavelength division multiplexers:
Described light isolation device is optoisolator.
8. it is characterized in that according to claim 5 or 6 described variable optical attenuation wavelength division multiplexers:
The exit end of described the 3rd birefringece crystal also is provided with half-wave plate.
9. adjustable optical attenuator according to claim 8 is characterized in that:
Light path between described half-wave plate and described the 3rd Dispersive Devices is provided with polarization spectro splicer spare.
10. it is characterized in that according to claim 5 or 6 described variable optical attenuation wavelength division multiplexers:
Be provided with at least one unidirectional extended device of light beam between the incident end of the exit end of described the 3rd birefringece crystal and described the 3rd Dispersive Devices.
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Cited By (3)
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| CN105241640A (en) * | 2015-11-24 | 2016-01-13 | 常州工学院 | Device for measuring blue light weighted radiation intensity and method thereof |
| CN108132500A (en) * | 2018-01-30 | 2018-06-08 | 福建天蕊光电有限公司 | A kind of closed loop optical circulator |
| CN112737683A (en) * | 2019-10-14 | 2021-04-30 | 华为技术有限公司 | Power equalizer and adjusting method thereof |
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| US6539148B1 (en) * | 1997-06-06 | 2003-03-25 | Novera Optics, Inc. | Channel equalizer with acousto-optic variable attenuators |
| CN102305771A (en) * | 2011-08-18 | 2012-01-04 | 天津大学 | Multi-waveband aliasing lumen gas sensing system and sensing method |
| CN102866534A (en) * | 2012-10-08 | 2013-01-09 | 南京大学 | Adjustable optical attenuator |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US6539148B1 (en) * | 1997-06-06 | 2003-03-25 | Novera Optics, Inc. | Channel equalizer with acousto-optic variable attenuators |
| CN102305771A (en) * | 2011-08-18 | 2012-01-04 | 天津大学 | Multi-waveband aliasing lumen gas sensing system and sensing method |
| CN102866534A (en) * | 2012-10-08 | 2013-01-09 | 南京大学 | Adjustable optical attenuator |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105241640A (en) * | 2015-11-24 | 2016-01-13 | 常州工学院 | Device for measuring blue light weighted radiation intensity and method thereof |
| CN105241640B (en) * | 2015-11-24 | 2018-08-17 | 常州工学院 | A kind of measuring device and its method of blue light weighting radiance |
| CN108132500A (en) * | 2018-01-30 | 2018-06-08 | 福建天蕊光电有限公司 | A kind of closed loop optical circulator |
| CN108132500B (en) * | 2018-01-30 | 2020-02-07 | 福建天蕊光电有限公司 | Closed loop optical circulator |
| CN112737683A (en) * | 2019-10-14 | 2021-04-30 | 华为技术有限公司 | Power equalizer and adjusting method thereof |
| CN112737683B (en) * | 2019-10-14 | 2023-05-16 | 华为技术有限公司 | Power equalizer and adjusting method thereof |
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| CN103076655B (en) | 2016-06-29 |
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