CN104506237A - Soliton optical transmission system - Google Patents
Soliton optical transmission system Download PDFInfo
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- CN104506237A CN104506237A CN201410504706.1A CN201410504706A CN104506237A CN 104506237 A CN104506237 A CN 104506237A CN 201410504706 A CN201410504706 A CN 201410504706A CN 104506237 A CN104506237 A CN 104506237A
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- soliton
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- 230000003287 optical effect Effects 0.000 title claims abstract description 59
- 230000005540 biological transmission Effects 0.000 title claims abstract description 53
- 239000013307 optical fiber Substances 0.000 claims abstract description 59
- 239000006185 dispersion Substances 0.000 claims abstract description 44
- 239000000835 fiber Substances 0.000 claims description 31
- 230000000694 effects Effects 0.000 claims description 12
- 238000001228 spectrum Methods 0.000 claims description 6
- 230000002547 anomalous effect Effects 0.000 claims description 5
- 238000005311 autocorrelation function Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 239000004065 semiconductor Substances 0.000 claims description 4
- 230000003321 amplification Effects 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims description 3
- 238000010168 coupling process Methods 0.000 claims description 3
- 238000005859 coupling reaction Methods 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 239000000047 product Substances 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 3
- 230000008602 contraction Effects 0.000 claims description 2
- 239000013589 supplement Substances 0.000 claims description 2
- 238000004891 communication Methods 0.000 abstract description 17
- 238000005516 engineering process Methods 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 3
- 230000010363 phase shift Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000005374 Kerr effect Effects 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000009022 nonlinear effect Effects 0.000 description 2
- 229910000679 solder Inorganic materials 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
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- 238000010586 diagram Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
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- 239000000377 silicon dioxide Substances 0.000 description 1
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- Optical Communication System (AREA)
Abstract
The invention relates to a soliton optical transmission system. Along with continuous expansion of a power grid service, the transmission speed and transmission distance of a power communication transmission system are increased. Along with the improvement in an optical fiber manufacturing process, the loss of an optical fiber is close to a theoretical limit, so that optical fiber dispersion becomes a problem to be solved in ultra-large-capacity optical fiber communication. A plurality of multiplexing technologies such as an optical time division multiplexing technology, an optical polarization-division multiplexing technology and an optical wavelength division multiplexing technology are adopted in soliton communication, so that the potential of increasing the transmission code rate is very high, and soliton is a specific transmission way of optical wave energy. First-order soliton transmission in an ideal optical fiber can keep the pulse shape of the optical fiber constant, and is an ideal way of high-speed long-distance optical transmission. Through soliton transmission, the problem of chromatic dispersion in optical transmission can be well solved.
Description
Technical field
The present invention relates to the communications field, particularly a kind of optical soliton optical transmission system.
Background technology
Along with the continuous expansion of electrical network business, the transmission rate of power communication transmission system is more and more higher, distance is more and more longer.
How when the long distance of two-forty, ensure that the quality of signal transmission becomes the task of top priority.In optical transmission system, the principal element of limit fibre communication two-forty, long range propagation is attenuation and the dispersion of optical fiber, and for the linear optical fiber communication system of routine, the principal element limiting its transmission capacity and distance is loss and the dispersion of optical fiber.
Along with the raising of fiber making processes, the loss of optical fiber is close to theoretical limit, and therefore optical fiber dispersion just becomes and realizes vast capacity optical fiber communication letter problem to be solved.The dispersion of optical fiber, make the light propagation velocity of different wave length in light pulse inconsistent, result causes optical pulse broadening, limits transmission capacity and transmission range, can be offset the effect of optical fiber dispersion by non-linear the produced optical soliton of optical fiber.
For chromatic dispersion, mainly realized by dispersion compensating fiber (DCF) or Fiber Bragg Grating (FBG) at present.Utilizing DCF to carry out dispersion compensation is the compensation scheme that application is maximum at present, because dispersion compensating fiber has negative dispersion coefficient, can offset the dispersion caused by conventional fiber.DCF structure is simple, technology maturation, but shortcoming is reduction of the net sectional area of optical fiber, adds loss, and have impact on nonlinear effect, needs the unnecessary gain utilizing image intensifer to compensate.Utilizing FBG to carry out dispersion compensation is make the light of different wave length experience different transmission paths, and the fast wavelength of transmission speed is by longer distance in grating, and slow-footed wavelength then experiences shorter distance.FBG has the features such as insertion loss is low, without effect, can as the replacement scheme of DCF.
When signal rate is lower, adopt fixing dispersion compensation, and along with the raising of signal rate, the increasing of system channel number, system all can be more responsive to the minor variations of some time-varying parameters, as the change etc. of aging, the route of device, therefore needs to carry out adjustable dispersion compensation to system. in addition, different due to the difference of the dispersion with wavelength of optical fiber, note also residual dispersion problem during dispersion compensation, need to adopt dispersion slope compensation, this adds increased the difficulty of compensation.
Summary of the invention
At a high speed, the basic difficulty that the development of long-distance optical fiber communication runs into is that the light pulse signal broadening that optical fiber dispersion causes causes adjacent code crosstalk.Theoretical and experiment proves, to the intensity modulated direct detection Fiber Optical Communication System of ultra-long span transmission, transmission speed is difficult to more than 10Gbit/s.In fact, divide because optical solition communication can adopt during light, light partially divides and light wave grades multiple multiplex technique, its transmission code rate has and improves potentiality greatly, and optical soliton is the specific transmission means of light-wave energy.Single order soliton propation in ideal fiber can keep fiber pulse shape invariance, is the ideal style of high speed long-distance optical communication.Due to waveform cyclic variation in transmitting procedure of high-order optical soliton, choose suitable fiber lengths, can realize light pulse compression, this is the effective means obtaining psec and Femtosecond Optical Pulses.Therefore, utilize optical soliton to carry out communication can address this problem well.
Light pulse is propagated in a fiber, light pulse can be caused to narrow when optical intensity density is enough large, and pulse duration is less than 1 Ps, and this is a kind of phenomenon in nonlinear optics, is called optical soliton phenomenon.Bandwidth of an optical fiber can be made to increase by 10 1 100 times if use optical soliton to carry out communication, communication distance and speed are improved significantly.
For the linear optical fiber communication system of routine, the principal element limiting its transmission capacity and distance is loss and the dispersion of optical fiber.Along with the raising of fiber making processes, the loss of optical fiber is close to theoretical limit, and therefore optical fiber dispersion just becomes and realizes vast capacity optical fiber communication letter problem to be solved.The dispersion of optical fiber, make the light propagation velocity of different wave length in light pulse inconsistent, result causes optical pulse broadening, limits transmission capacity and transmission range.The effect of optical fiber dispersion can be offset by non-linear the produced optical soliton of optical fiber.
The principle of soliton propation, the formation of optical soliton owing to the non-linear Self-phase modulation of optical fiber and effect of dispersion to the balanced action of light pulse.When the light pulse with certain spectral width is transmitted in dispersive optical fiber, its different frequency composition has different transmission speed, therefore the continuous broadening of light impulse length.If light pulse power is comparatively strong, when having obvious nonlinear effect (Kerr effect) in a fiber during transmission, transmission characteristic has significant change.Due to Kerr effect, the refractive index of optical fiber can be expressed as:
n＝n
0+n
2I (1)
N in formula
0for constant, Section 2 shows that the refractive index of optical fiber is relevant with the light intensity I of transmission, n: be nonlinear viscoelastic piles, for silica fiber, and n
2=3 × 10
-20m
2/ W.When after light pulse in a fiber transmission range z, produce the phase shifts relevant with light intensity
Light pulse has different light intensity instantaneously at different frequency, thus has different phase shifts.Because of the phase shift that the change of light field itself causes, be called Self-phase modulation.The frequency shifts that Self-phase modulation causes is
Light pulse forward position
Δ ω <o, rear edge
Δ ω >o.In the main region that light intensity is stronger, forward position frequency is on the low side, rear higher along frequency.In the anomalous dispersion region of optical fiber, dispersion parameters
(V
gfor group velocity), the composition group velocity that optical pulse frequency is low is little, and the composition group velocity that frequency is high is large, and therefore slack-off, the rear edge of pulse front edge accelerates, and light pulse is compressed.When non-linear pinch effect and effect of dispersion balance, light pulse keeps waveform constant when transmitting, be referred to as single order optical soliton.Because nonlinear refractive index is relevant with light intensity, when therefore only having light pulse peak power to exceed certain value, optical soliton could be formed.
The theoretical foundation of arc transmission is the stunned equation of non-linear Xue Ding, separate the light pulse transmission characteristic in a fiber that this equation can draw various electrical field envelope form, the stable solution of this equation is the hyperbolic secant optical pulse of normalized amplitude A=1, its corresponding single order optical soliton, and the waveform of other high-order arcs is periodically variable in transmitting procedure, the constant P that normalized parameter A and light pulse peak power P and optical fiber parameter, light impulse length determine
1between meet:
P
1＝0.776λ
3A
eD/πCn
2τ
2(4)
In formula, λ, τ are respectively light pulse wavelength and pulsewidth, A
e, D is effective core area and the anomalous dispersion amount of optical fiber.In harmless optical fiber, if incident light pulse peak power P=P
1time, the undistorted transmission of single order arc can be formed.If there is loss in optical fiber, light pulse contraction index decay in the transmission, pulse duration index increase, and pulse area is constant, as long as just can recover shape to light pulse makeup energy, thus realizes long range propagation.Lump type erbium-doped fiber image intensifer (EDFA) periodically makeup energy can be adopted, namely in optical fiber link, every distance L
aarrange a fiber amplifier, its gain supplements fibre loss just.
Soliton sources are gain-switching semiconductor lasers, with 2.5GHz Sine Current Modulation, and disappeared by FP spectrum window and warble, obtain wavelength 1.553 μm, pulsewidth is 18ps, time-bandwidth product be 0.324 nearly transform limit light pulse.Light pulse is put after device amplifies through two optical fiber and is injected 21km dispersion shifted optical fiber (DSF).EDFA
1and EDFA
2respectively by 1480nm and 980nmLD pumping, pump light injects erbium-doped fiber through wavelength division multiplexing coupling apparatus, under the effect of pump light, and Er
+ 3ion
4i
15/2with
4i
13/2population inversion can be formed by inter-stage, have amplification to 1550nm flashlight.DSF is made up of three sections of anomalous dispersion (D>0) fused fiber splices, mean dispersion D=2.4ps/kmnm, and total losses (comprising solder joint and two optical fiber splices) are 7dB.
EDFA is mainly made up of one section of Er-doped fiber (being about 10 ~ 30m) and pump light source, its operation principle is: after luminous energy is pumped to, the erbium being entered certain length by optical multiplexer adds light pricker, the latter is carried in luminous energy on the light signal of input as a kind of conversion medium, light signal enters unit with certain power, when going out, power just increases, and optical isolator is unwanted reflected signal filtering.
Incident light pulse and after Optical Fiber Transmission the width of output optical pulse measure by second harmonic intensity autocorrelation function analyzer (SHG).Judging whether to be the basic skills realizing soliton propation is compare the width of optical fiber constrained input light pulse, if output optical pulse width τ
outthe width τ of≤bunch input optical pulse
in, then soliton propation is achieved.
Accompanying drawing explanation
Fig. 1 is the structural representation of optical soliton optical transmission system of the present invention;
Fig. 2 is the transmission different distance optical pulse waveform schematic diagram of optical soliton optical transmission system of the present invention.
Embodiment
Optical soliton optical transmission system of the present invention is primarily of power supply (AC, DC), soliton sources, spectrum window (FP), controller, coupler, image intensifer (EDFA
1, EDFA
2), dispersion shifted optical fiber, power meter and autocorrelation function analyzer composition, soliton sources are gain-switching semiconductor laser (DFB), with 2.5GHz Sine Current Modulation, and disappeared by FP spectrum window and warble, obtain wavelength 1.553 μm, pulsewidth be 18ps, time-bandwidth product be 0.324 nearly transform limit light pulse.Light pulse puts device EDFA through two optical fiber
1and EDFA
221km dispersion shifted optical fiber (DSF) is injected after amplifying.EDFA
1and EDFA
2respectively by 1480nm and 980nmLD pumping, pump light injects erbium-doped fiber through wavelength division multiplexing coupling apparatus, under the effect of pump light, and Er
+ 3ion
4i
15/2with
4i
13/2population inversion can be formed by inter-stage, have amplification to 1550nm flashlight.DSF is made up of three sections of anomalous dispersion (D>0) fused fiber splices, mean dispersion D=2.4ps/kmnm, and total losses (comprising solder joint and two optical fiber splices) are 7dB.
Incident light pulse and after Optical Fiber Transmission the width of output optical pulse measure by second harmonic intensity autocorrelation function analyzer (SHG).Judging whether to be the basic skills realizing soliton propation is compare the width of optical fiber constrained input light pulse, if output optical pulse width τ
outthe width τ of≤bunch input optical pulse
in, then soliton propation is achieved.
As calculated, when the average power of incident light is less, the non-linear self phase modulation of optical fiber is extremely weak and fiber dispersion effects is preponderated, light pulse by 18Ps broadening during incidence to 27.ZPs.Because self phase modulation strengthens with the increase of incident optical power, when average power is 1.smw, self phase modulation and dispersion mudulation effect compensate just, optical fiber exports with input pulse width suitable, forms single order soliton propation, when input power is greater than 1.smw, high-order arc effect will make pulse duration narrow, when average power is 6.Zmw, pulse duration is compressed to 4.sps, and compression ratio is 3.75.
In order to analyze Gain-Switched DFB Laser as soliton sources transmission system characteristic and this to tick through disappearing sing after the nearly transform limit light pulse that obtains can be used for the soliton propation of long distance, we utilize nonlinear Schrodinger equation analog computation through FP spectrum window disappear favore with sing after light pulse to damage transmission in optical fiber at 5000km.Arrange an amplifier (EDFA) with electrode compensation every 25km in Transmission Fibers, transmission different distance optical pulse waveform is as Fig. 2, and can find out, above-mentioned light pulse stably can transmit 5000km.It can be said that bright gain-switching semiconductor laser is after process sung in the tune that disappears, and can not only realize short distance soliton propation as during soliton sources, and the long stable distance transmission of thousands of miles can be realized.
Claims (3)
1. an optical soliton optical transmission system, is characterized in that: by power supply (AC, DC), soliton sources, spectrum window (FP), controller, coupler, image intensifer (EDFA
1and EDFA
2), dispersion shifted optical fiber, power meter and autocorrelation function analyzer composition, soliton sources are gain-switching semiconductor laser (DFB), with 2.5GHz Sine Current Modulation, and disappeared by FP spectrum window and warble, obtain wavelength 1.553 μm, pulsewidth be 18ps, time-bandwidth product be 0.324 nearly transform limit light pulse;
Light pulse puts device EDFA through two optical fiber
1and EDFA
221km dispersion shifted optical fiber (DSF) is injected, EDFA after amplifying
1and EDFA
2respectively by 1480nm and 980nmLD pumping, pump light injects erbium-doped fiber through wavelength division multiplexing coupling apparatus, under the effect of pump light, and Er
+ 3ion
4i
15/2with
4i
13/2can form population inversion by inter-stage, have amplification to 1550nm flashlight, DSF is made up of three sections of anomalous dispersion (D>0) fused fiber splices, mean dispersion D=2.4ps/kmnm, and total losses are 7dB;
Incident light pulse and after Optical Fiber Transmission the width of output optical pulse measure by second harmonic intensity autocorrelation function analyzer (SHG), judging whether to be the basic skills realizing soliton propation is compare the width of optical fiber constrained input light pulse, if output optical pulse width τ
outthe width τ of≤bunch input optical pulse
in, then soliton propation is achieved.
2. a kind of optical soliton optical transmission system according to claim 1, it is characterized in that: in described dispersion shifted optical fiber, there is loss, light pulse contraction index decay in the transmission, pulse duration index increase, pulse area is constant, just shape can be recovered to light pulse makeup energy, thus realize long range propagation, lump type erbium-doped fiber image intensifer (EDFA) periodically makeup energy can be adopted, in optical fiber link, arrange a fiber amplifier every distance La, its gain supplements fibre loss just.
3. a kind of optical soliton optical transmission system according to claim 1, is characterized in that: described image intensifer is made up of one section of Er-doped fiber (being about 10 ~ 30m) and pump light source.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410504706.1A CN104506237A (en) | 2014-09-26 | 2014-09-26 | Soliton optical transmission system |
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|---|---|---|---|
| CN201410504706.1A CN104506237A (en) | 2014-09-26 | 2014-09-26 | Soliton optical transmission system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112073120A (en) * | 2020-09-14 | 2020-12-11 | 长沙航空职业技术学院 | Photoelectric signal processing method and system based on optical solitons |
| CN116805889A (en) * | 2023-08-21 | 2023-09-26 | 深圳市光为光通信科技有限公司 | Optical fiber transceiver module based on CPO technology |
-
2014
- 2014-09-26 CN CN201410504706.1A patent/CN104506237A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112073120A (en) * | 2020-09-14 | 2020-12-11 | 长沙航空职业技术学院 | Photoelectric signal processing method and system based on optical solitons |
| CN112073120B (en) * | 2020-09-14 | 2021-07-20 | 长沙航空职业技术学院 | Photoelectric signal processing method and system based on optical solitons |
| CN116805889A (en) * | 2023-08-21 | 2023-09-26 | 深圳市光为光通信科技有限公司 | Optical fiber transceiver module based on CPO technology |
| CN116805889B (en) * | 2023-08-21 | 2023-11-10 | 深圳市光为光通信科技有限公司 | Optical fiber transceiver module based on CPO technology |
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Application publication date: 20150408 |