| With the rapid development of "5G" communications and the Internet of Things,the demand for information transmission rate and bandwidth is increasing day by day,and high-speed information processing technology has subsequently become a research hotspot in the field of optical fiber communication.As the core technology of the future high-speed all-optical network,all-optical information processing has the advantages of large bandwidth,low delay,and transparent modulation format.Optical signals will be affected by some degrading factors such as the noise and distortion induced through the long-distance transmission.All-optical regeneration technology can be used to improve the quality of signals in the optical domain,bypassing the electronic bottlenecks and complex structures caused by the traditional optical-electrical-optical information processing methods.To further improve the flexible configuration function of all-optical regenerators with application to coherent and incoherent optical transmission systems,this thesis focuses on two all-optical regeneration schemes of nonlinear optical loop mirrors(NOLMs)and semiconductor optical amplifiers(SOAs),respectively.We carry out the detail research on all-optical regeneration technology compatible with both the On-off Keying(OOK)and Quadrature Phase Shift Keying(QPSK)formats to further improve the flexibility of all-optical regenerators in complex network environments.The main research contents and innovations of the thesis are as follows:1.Through the experimental testing of the stimulated Brillouin scattering threshold in the highly nonlinear fiber(HNLF),the length parameter of HNLF in the NOLM regenerator was optimized,and we built up the simulation and experiment platforms of the NOLM regenerator structure to study the influence of the fiber coupler on the inputto-output power transfer function(PTF).Due to the narrow working range of traditional NOLM regenerators,a non-linear optical loop mirror based on polarization-maintaining coupler(PMC-NOLM)is innovatively proposed.Experimental results show that the PMC-NOLM structure can greatly increase the PTF's saturation region,the regenerative region exceeds to 15 d B;and the maximum Q-factor improvement of 3.5d B can be obtained at the input power of 22.75 d Bm.2.According to the carrier rate equation and the light-field transmission equation in the SOA theoretical model,the quasi-steady state evolution process of the light field amplitude under the action of four-wave mixing in SOA is studied.Based on the principle of optical parametric amplification in a nonlinear SOA,the all-optical regeneration of both OOK and QPSK signals is realized by optimizing the pump-to-signal power ratio(PSR).(1)The regeneration ability of SOA is studied for the pattern distortion of OOK optical signal by adjusting the parameters of PSR,input signal-to-noise ratio(SNR),data rate and wavelength.Experimental results show that,when PSR=9d B,the SOA regenerator can improve the SNR of the distorted 10Gb/s optical OOK signal with the wavelength of 1550.92 nm up to 3.9d B.(2)The noise suppression performance of SOA for the 10Gb/s optical QPSK signal is studied.When PSR=13.6d B,the regenerative region of input optical signal-to-noise ratio(OSNR)is 17.3?22d B,with a maximum SNR improvement of 3.2d B at the input OSNR of 18.2d B. |
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