| All-optical regeneration is likely to be one of key technologies for future all optical communication systems, as it can process signal in optical domain directly without complicated O-E-O conversion in electronic domain, increase the capacity, enhance the scalability and flexibility, and reduce the network management complexity and costs. Over the past few years, there numerous all-optical regeneration schemes have been reported. Among them, self-phase-modulation (SPM) and offset filtering based regenerator using highly nonlinear fiber is one of the hot topics due to its simplicity, robustness, low cost and high speed.In this work, we simulat a basic numerical model for the SPM-based all optical regenerator utilizing the nonlinear Schrodinger equation, firstly. Then, performance analysis and optimization for two-type SPM-based regenerator are investigated numerically using split-step Fourier methods. The main content includes:(1) For the one-stage SPM-based all-optical regenerator, we optimize the peak power of the input signal and wavelength offset of the offsetting filter form the standpoint of amplitude-jitter suppression and ghost-pulse reduction, under fixing the fiber parameters, the bandwidth of the offsetting filter and pulse-width of the input signal. Compared the Q-factor before and after the regenerator, a optimal relationship between the peak power of the input signal and wavelength offset of the offsetting filter is obtained which is fund to be a quadratic relationship after numerical fitting.(2) For the cascaded SPM-based all-optical regenerator, we consider a structure which is consisted of two one-stage SPM-based all-optical regenerator, but with opposite wavelength offset, for ensuring no wavelength discrepancy after regeneration. The simulation results show that the regeneration performance is improved by using tow staged SPM-based all-optical regenerator, and up to 2-dB Q-factor improvement is achieved compared to one-staged regenerator. |
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