强脉冲信号在光纤参变放大器中的放大特性研究

考虑到抽运损耗、走离、色散和非线性等效应，用分步傅里叶方法求解耦合的非线性薛定谔方程组，就强脉冲信号在连续光抽运光纤参变放大器中的放大情况进行了理论研究。研究结果表明，强脉冲信号除经历振幅放大，脉冲时域展宽等过程外，还会发生令人感兴趣的脉冲分裂现象，即一个脉冲信号分裂为两个子脉冲。而且即使在连续光抽运的情况下，走离效应对强脉冲信号的放大也产生了显著影响，即促使两个子脉冲振幅不等以及脉冲漂移。最后，强脉冲信号独特的放大特性用光纤参变放大器的饱和增益特性做了很好的解释，并指出脉冲分裂现象在信号抽样、脉冲压缩、光时分复用系统中有潜在用途。

Investigation on the Amplification of Strong Pulse Signal in Fiber Optical Parametric Amplifiers

Considering pump depletion, walk-off effect, dispersion and nonlinear effect on pulses propagating inside optical fibers, amplification of intense pulse signal in fiber optical parametric amplifiers (FOPA) are numerically studied by solving the coupled nonlinear Schrdinger equations with split-step Fourier method. Calculation results showed that, except amplitude amplification and temporal width broadening, a very interesting phenomenon occurred that is one signal pulse splitting into two sub-pulses. Further, even if in the case of continous wave pumped, walk-off does have distinct effect on the amplification of strong pulse signal, leading to amplitude difference for two sub-pulses and pulse shift. At last, the unique strong pulse signal amplification characteristics are finely explained by saturated gain properties of FOPA, and the potential applications of pulse splitting phenomenon in pulse compression, signal sampling and time-division multiplex system are pointed out as well.