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CN104301036A - A device for extracting optical clock based on nonlinear halo mirror - Google Patents

A device for extracting optical clock based on nonlinear halo mirror Download PDF

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Publication number
CN104301036A
CN104301036A CN201410484712.5A CN201410484712A CN104301036A CN 104301036 A CN104301036 A CN 104301036A CN 201410484712 A CN201410484712 A CN 201410484712A CN 104301036 A CN104301036 A CN 104301036A
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optical
signal generator
light signal
output
generator
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曹永盛
王进
卢学嘉
张思越
贾溢豪
赵安臻
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University of Electronic Science and Technology of China
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University of Electronic Science and Technology of China
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Abstract

The invention provides an optical clock extraction device based on a non-linear optical loop mirror (NOLM). The optical clock extraction device conducts optical clock extraction based on the NOLM, the NOLM can extract an optical clock portion carried by original hard light signals after processing optical signals, and then optical signals output by the output end of the NOLM can reproduce information of inputting the optical signals completely. In order to ensure that the signals have an enough sampling rate on data signals, the transmission rate of probe light signals is at least twice that of a hard light signal generator. After the optical signals are processed in the NOLM, the clock extraction process in an electric domain is greatly simplified, and excessive electric domain processing is eliminated. The NOLM can process probe light signals at a higher rate, the probe light signals are used for sampling and extracting an optical clock, and the higher the transmission rate of the probe light signals is, the higher the sampling rate is, so the accuracy of the obtained clock is higher.

Description

The device that a kind of Optical Clock based on Nonlinear optical loop mirror extracts
Technical field
The present invention relates to optical communication and optical information processing technology, particularly a kind of novel Optical Clock extractive technique based on Nonlinear optical loop mirror.
Background technology
At present, the transmission capacity of optical communication backbone network can reach 10Tb/s, but in optical communication network, the major obstacle that communication capacity improves realizes exchanging by electrical domain method because network is also in.Therefore just must break for improving network communications capability the bottleneck that electricity exchanges and light/electrical/optical is changed.Because existing high-speed transfer circuit all adopts Optical Fiber Transmission mode, therefore All-optical switching breaks electricity to exchange bottleneck, and improve the development trend of network communication capacity.The future development target of all optical network (AON, All-Optical Network) all optical communication especially.In digital optical, the correct extraction of Optical Clock is then improve the light signal quality of reception, ensures the important guarantee that all-optical network normally works.
In existing optical communication network, due to the effect of dispersion that the light signal of fiber nonlinear effect and different wave length is caused in a fiber, make light signal in receiving course, the shake of meeting accumulation clock and drift, this Optical Clock that greatly have impact on receiving terminal extracts, and and then has influence on the received signal quality of receiving terminal and the noiseproof feature of signal.Therefore, from the high-speed optical signal with clock jitter or drift, correctly recovering Optical Clock becomes study hotspot in Modern High-Speed optical communication system day by day, has important Practical significance.
At present, the extraction scheme of Optical Clock is the extracting method based on electric clock mostly, by using opto-electronic conversion and a large amount of electrical domain process, from light signal, extracts Optical Clock.Because light process to differ very large with the ability of electric treatment, therefore existing Optical Clock extraction scheme all exists that speed is low, the processing time long, it is high and extract the shortcomings such as Optical Clock low precision to realize cost.
Summary of the invention
Technical problem to be solved by this invention is, the device that the Optical Clock making Optical Clock extract the too much electrical domain process of release extracts.
The present invention for solving the problems of the technologies described above sampled technical scheme is, the device that a kind of Optical Clock based on Nonlinear optical loop mirror extracts, and comprises high light signal generator, detection optical signal generator, electrical domain Clock Extraction module, Nonlinear optical loop mirror;
Described Nonlinear optical loop mirror comprises the three-dB coupler of high light signal generator side, three-dB coupler, semiconductor optical amplifier, the three-dB coupler of light signal outlet side, monomode fiber, the high non-linearity HNLF optical fiber of detection optical signal generator side;
The detection light signal of the output of described detection optical signal generator and high light signal generator and the wavelength of output high light signal identical, detection optical signal transmission speed is 2 of high light signal generator transmission rate ndoubly, n=1,2,
The output of high light signal generator, an output of detection optical signal generator are connected respectively by the input of monomode fiber with the three-dB coupler of high light signal generator side; The output of the three-dB coupler of high light signal generator side is connected with the input of semiconductor optical amplifier by monomode fiber, and the output of semiconductor optical amplifier is connected by the input of monomode fiber with the three-dB coupler of light signal outlet side; Another output of detection optical signal generator is connected with the input of the three-dB coupler of light signal outlet side by HNLF optical fiber, export after the three-dB coupler of the light signal outlet side two ways of optical signals to input carries out Cross-phase Modulation carry Optical Clock light signal to electrical domain Clock Extraction module, electrical domain Clock Extraction module extracts standard clock signal according to from the light signal carrying Optical Clock.
The present invention is based on Nonlinear optical loop mirror (NOLM, Nonlinear Optical Loop Mirror) carry out Optical Clock extraction, after NOLM processes light signal, can by the Optical Clock extracting section of carrying in original high light signal out, the light signal that such NOLM output exports can the information of complete reproduction input optical signal.In order to data signal signal among ensureing has enough sample rates, detection optical signal transmission speed is at least 2 times of high light signal generator transmission rate.
After light signal processes by the present invention in NOLM, the Clock Extraction process in electrical domain can be made greatly to be simplified, to exempt too much electrical domain process.Because NOLM can process the detection light signal of higher rate, detection light signal is used for sampling to Optical Clock and extracting, and detection optical signal transmission speed is higher, and sample rate is higher, and then the clock accuracy obtained is also higher.
The invention has the beneficial effects as follows, it reduce the system complexity of existing Clock Extraction scheme and realize cost, there is very strong actual operability.
Accompanying drawing explanation
Fig. 1 is the operation principle schematic diagram of NOLM in the present invention;
Fig. 2 is the optical signal prosessing module frame chart based on NOLM in the present invention;
Fig. 3 is the waveform of high light signal in the present invention;
Fig. 4 is the output optical signal waveform obtained after NOLM process in the present invention;
Fig. 5 is electrical domain Clock Extraction module frame chart in the present invention;
Fig. 6 be in the present invention signal after electrical domain Clock Extraction module, the clock signal waveform obtained.
Embodiment
As shown in Figure 1, the present invention is based on Nonlinear optical loop mirror (NOLM, Nonlinear Optical Loop Mirror) and carry out Optical Clock extraction, first will carry the high light signal unbalanced input optical loop mirror of data.After detection light signal enters NOLM, the two paths of signals of constant power is divided into by three-dB coupler, two paths of signals is in NOLM, and the clockwise CW of a curb (Clock Wise) direction is transmitted, CCW (Counter Clock Wise) direction transmission that another curb is counterclockwise.One tunnel detection light signal and the high light signal propagated of CW direction transmit simultaneously, and the light signal that Cross-phase Modulation (the XPM:Cross Phase Modulation) effect of two-way light can make CW direction propagate and the light signal that CCW direction is propagated produce additional phase shift; The three-dB coupler of this two ways of optical signals to light signal outlet side after NOLM transmission carries out secondary interference, and exports from the output port of the three-dB coupler of outlet side.Output depends on the phase difference between two ways of optical signals with or without the output of light signal.When high light signal is logical one, phase difference △ φ=π, detection light signal exports from output completely; When high light signal is logical zero, phase difference △ φ=0, it is then " 0 " that output exports.
The device extracted based on the Optical Clock of Nonlinear optical loop mirror as shown in Figure 2, original strong optical signals distributed feed-back (DFB, Distributed Feed-Back) laser DFB 1, pseudo random sequence (PRBS:Pseudo-random Binary Sequence) generator PRBS 1, non-return-to-zero (NRZ, Non Return-to-Zero) pulse generator 1 produce with the Mach-Zehnder modulator MZM 1 for light intensity modulation; Detection optical signals laser DFB 2, pseudo-random sequence generator PRBS 2, NRZ pulse generator 2 produce with Mach-Zehnder modulator MZM 2;
The output of laser DFB 1 is connected with the carrier input of modulator MZM 1, the output of pseudo-random sequence generator PRBS 1 is connected with the input of NRZ pulse generator 1, the output of NRZ pulse generator 1 is connected with the modulation signal input of modulator MZM 1, and the output of modulator MZM 1 exports the original high light signal carrying data.
The output of laser DFB 2 is connected with the carrier input of modulator MZM 2, the output of pseudo-random sequence generator PRBS 2 is connected with the input of NRZ pulse generator 2, the output of NRZ pulse generator 2 is connected with the modulation signal input of modulator MZM 1, and the output of modulator MZM 2 exports detection light signal.
NOLM comprises the three-dB coupler 1 of high light signal generator side, detection three-dB coupler 2, one section of high non-linearity HNLF optical fiber (High Non-Linear Fiber) of optical signal generator side, monomode fiber, semiconductor optical amplifier SOA (Semiconductor Optical Amplifier), three-dB coupler 3 output ports as NOLM, realizes the Cross-phase Modulation to two ways of optical signals.The output of three-dB coupler 1 is connected with the input of SOA by monomode fiber, the output of SOA is connected with the upper input of three-dB coupler 3 by monomode fiber, the upper output of three-dB coupler 2 is connected with the upper input of three-dB coupler 1 by monomode fiber, the output of the lower input high light signal of three-dB coupler 1 is connected, the output of detection light signal is connected with the input of three-dB coupler 2, and the lower output of three-dB coupler 2 is connected with the lower input of three-dB coupler 3 by HNLF optical fiber.
Wherein laser DFB 1, pseudo-random sequence generator PRBS 1, nonreturn-to-zero pulse generator 1 produce with Mach-Zehnder modulator MZM 1 the original high light signal that speed is 10Gb/s, average transmit power is 200mW, wavelength is 1552.52nm (193.1THz); Laser DFB 2, pseudo-random sequence generator PRBS 2, NRZ pulse generator 2 and the detection light signal that Mach-Zehnder modulator MZM 2 produces 40Gb/s, average transmit power is 2mW, wavelength is 1552.52nm (193.1THz).Herein, in order to ensure that clock signal has sufficiently high sample rate to data-signal, according to Nyquist sampling theorem, the bit rate of PRBS 2 at least should be the twice of PRBS 1 bit rate.In reality, for ensureing to realize the higher quality of reception, if the bit rate of PRBS 2 is 4 times of PRBS 1 bit rate.
After generating high light signal and detecting light signal, two paths of signals input NOLM device.High light signal of setting out on a journey directly inputs three-dB coupler 1, lower road detection light signal carries out decaying (herein through optical attenuator, arranging optical attenuator is to simulate the signal attenuation that in practical application, data-signal is existing in the transmission) after, be divided into upper and lower two-way by three-dB coupler 2 again, wherein setting out on a journey inputs in three-dB coupler 1 with high light signal.After the NOLM device that detection light signal in lower road is formed through highly nonlinear optical fiber (HNLF, High Non-Linear Fiber), the lower input port of input three-dB coupler 3.Herein, the length of HNLF is 1000 meters, and fibre loss is 0.8dB/km, and abbe number is 1.6 × 10 -6s/m 2, non linear coefficient is 2.6 × 10 -25m 2/ W.On the other hand, the detection light signal of high light signal and 50% intensity is after three-dB coupler 1 is coupled, amplify through semiconductor optical amplifier (SOA:Semiconductor Optical Amplifier) again, finally, the upper input port of input three-dB coupler 3, and obtain the light signal after the process of NOLM device.
Figure 3 shows that original high light signal waveform, Figure 4 shows that the output optical signal waveform obtained after the process of NOLM device, in this signal, contain obvious Optical Clock peak signal.
Electrical domain Clock Extraction module as shown in Figure 5, comprises photodiode PD, electric band pass filter BPF, edge detector, 1 bit (0.1ns) delayer, XOR gate, Hilbert transformer, electric low pass filter LPF and threshold value decision device and forms.The input optical signal of this part comes from the output signal of the device of NOLM shown in Fig. 2, carries the optical clock signal of peak value in this signal.This signal carries out opto-electronic conversion through PD, and by band pass filter and edge detector filtered signal noise and burrs on edges.Afterwards, signal is divided into upper and lower two-way, and lower road signal, after 1 bit (0.1ns) postpones, inputs partial sum gate and carries out XOR process together with signal of setting out on a journey; The signal obtained, again after Hilbert transform, by electric low pass filter (LPF:Low-pass Filter) filtering noise, eventually passes threshold value judgement, just can extract clock signal.
Figure 6 shows that the 40Gb/s optical clock signal extracted.
To sum up, the present invention adopts NOLM to process light signal, and therefrom extracts optical clock signal.This greatly reduces the system complexity of existing Optical Clock extraction module and realizes cost, and this invention is simultaneously simple, easy, cost is low, makes the leaching process of Optical Clock have more actual operability.
In a word; the foregoing is only preferred embodiment of the present invention; not only for limiting protection scope of the present invention; should be understood that; for those skilled in the art; in content disclosed by the invention, can also make some equivalent variations and replacement, these equivalent variations and replacement also should be considered as protection scope of the present invention.

Claims (5)

1.一种基于非线性光环镜的光时钟提取的装置，其特征在于，包括强光信号发生器、探测光信号发生器、电域时钟提取模块、非线性光环镜；1. A device for extracting an optical clock based on a nonlinear halo mirror, characterized in that it includes a strong light signal generator, a detection optical signal generator, an electrical domain clock extraction module, and a nonlinear halo mirror; 所述非线性光环境包括强光信号发生器侧的3dB耦合器、探测光信号发生器侧的3dB耦合器、半导体光放大器、光信号输出侧的3dB耦合器、单模光纤、高非线性HNLF光纤；The nonlinear optical environment includes a 3dB coupler on the strong optical signal generator side, a 3dB coupler on the detection optical signal generator side, a semiconductor optical amplifier, a 3dB coupler on the optical signal output side, a single-mode fiber, a highly nonlinear HNLF optical fiber; 所述探测光信号发生器的输出的探测光信号与强光信号发生器与的输出强光信号的波长相同，探测光信号传输速率是强光信号发生器传输速率的2n倍，n＝1,2,…；The detection light signal output by the detection light signal generator has the same wavelength as the output strong light signal of the strong light signal generator, and the transmission rate of the detection light signal is 2 n times the transmission rate of the strong light signal generator, n=1 ,2,…; 强光信号发生器的输出端、探测光信号发生器的一个输出端分别通过单模光纤与强光信号发生器侧的3dB耦合器的输入端相连；强光信号发生器侧的3dB耦合器的输出端通过单模光纤与半导体光放大器的输入端相连，半导体光放大器的输出端通过单模光纤与光信号输出侧的3dB耦合器的输入端相连；探测光信号发生器的另一个输出端通过HNLF光纤与光信号输出侧的3dB耦合器的输入端相连，光信号输出侧的3dB耦合器对输入的两路光信号进行交叉相位调制后输出携带有光时钟的光信号至电域时钟提取模块，电域时钟提取模块根据从携带有光时钟的光信号中提取出标准时钟信号。The output end of the strong light signal generator and one output end of the detection light signal generator are respectively connected to the input end of the 3dB coupler on the side of the strong light signal generator through a single-mode fiber; the 3dB coupler on the side of the strong light signal generator The output end is connected to the input end of the semiconductor optical amplifier through a single-mode optical fiber, and the output end of the semiconductor optical amplifier is connected to the input end of the 3dB coupler on the optical signal output side through a single-mode optical fiber; the other output end of the detection optical signal generator is passed through The HNLF fiber is connected to the input end of the 3dB coupler on the optical signal output side. The 3dB coupler on the optical signal output side performs cross-phase modulation on the two input optical signals and then outputs the optical signal carrying the optical clock to the electrical domain clock extraction module. , the electrical domain clock extracting module extracts the standard clock signal from the optical signal carrying the optical clock. 2.如权利要求1所述一种基于非线性光环镜的光时钟提取的装置，其特征在于，所述强光信号发生器与探测光信号发生器均包括激光器、伪随机序列发生器、非归零脉冲发生器、光强度调制器；2. a kind of device based on the optical clock extraction of nonlinear halo mirror as claimed in claim 1, is characterized in that, described strong light signal generator and detection light signal generator all comprise laser, pseudo-random sequence generator, non-linear Return to zero pulse generator, light intensity modulator; 所述激光器的输出端与光强度调制器的载波输入端相连，伪随机序列发生器的输出端与非归零脉冲发生器的输入端相连，非归零脉冲发生器的输出端与光强度调制器的调制信号输入端相连，光强度调制器的输出端为强光信号发生器或探测光信号发生器输出端；探测光信号发生器中的伪随机序列发生器与非归零脉冲发生器的输出的信号速率是强光信号发生器中的伪随机序列发生器与非归零脉冲发生器的输出的信号速率的2n倍，所述探测光信号发生器中的激光器与强光信号发生器中激光器输出光的波长相同。The output end of the laser is connected to the carrier input end of the optical intensity modulator, the output end of the pseudo-random sequence generator is connected to the input end of the non-return-to-zero pulse generator, and the output end of the non-return-to-zero pulse generator is connected to the light intensity modulator The modulation signal input terminal of the optical intensity modulator is connected, and the output terminal of the optical intensity modulator is the output terminal of the strong optical signal generator or the detection optical signal generator; the pseudo-random sequence generator in the detection optical signal generator and the non-return-to-zero pulse generator The output signal rate is 2 n times of the output signal rate of the pseudo-random sequence generator and the non-return-to-zero pulse generator in the strong light signal generator, and the laser in the detection light signal generator and the strong light signal generator The wavelength of the output light of the laser is the same. 3.如权利要求2所述一种基于非线性光环镜的光时钟提取的装置，其特征在于，所述光强度调制器为马赫-曾德MZM调制器。3. A device for extracting an optical clock based on a nonlinear halo mirror as claimed in claim 2, wherein the optical intensity modulator is a Mach-Zehnder MZM modulator. 4.如权利要求1所述一种基于非线性光环镜的光时钟提取的装置，其特征在于，非线性光环镜中还包括光衰减器，探测光信号发生器的输出端经光衰减器后与探测光信号发生器侧的3dB耦合器的输入端相连。4. a kind of device based on the optical clock extraction of nonlinear halo mirror as claimed in claim 1, is characterized in that, also comprises optical attenuator in the nonlinear halo mirror, detects the output end of optical signal generator after optical attenuator Connect to the input end of the 3dB coupler on the detection optical signal generator side. 5.如权利要求1所述一种基于非线性光环镜的光时钟提取的装置，其特征在于，n＝2。5. A device for extracting an optical clock based on a nonlinear optical loop mirror as claimed in claim 1, wherein n=2.
CN201410484712.5A 2014-09-19 2014-09-19 A device for extracting optical clock based on nonlinear halo mirror Pending CN104301036A (en)

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CN106788728A (en) * 2017-01-16 2017-05-31 中国科学技术大学 Light signal detection method under high light interference
CN107171736A (en) * 2017-05-18 2017-09-15 杭州电子科技大学 Full light samples device

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Publication number Priority date Publication date Assignee Title
CN106788728A (en) * 2017-01-16 2017-05-31 中国科学技术大学 Light signal detection method under high light interference
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