噪音对飞秒脉冲在光子晶体光纤中传输特性的影响

Influence of Noise on the Propagation Character of Femtosecond Pulse in Photonic Crystal Fiber

从非线性薛定谔方程出发,采用线性稳定性的分析理论和分布傅里叶的数值模拟方法,研究了噪音对飞秒脉冲在两个零色散波长光子晶体光纤中传输特性的影响和超连续谱的产生.研究结果表明,在传输的初始阶段,无论有无噪音,频谱展宽的主要机制都是自相位调制;但噪音加快了脉冲的分裂,产生色散波所经历的传输距离比没有噪音时要短.在传输的后续阶段,高阶孤子分裂产生基态孤子,与没有加入噪音时相比,噪音不仅减弱了孤子走离效应,而且还抑制了孤子自频移效应,使得从反常色散区转移至长波长处的能量变少.

Using linear stability analysis and the standard split-step Fourier method, the influence of noise on the propagation character of femtosecond pulse and the generation of supercontinuum spectrum were studied in photonic crystal fibers with two zero dispersion wavelengths according to nonlinear Schrdinger equation.The results show that the initial spectral broadening is mainly due to SPM whatever there has noise or not,but noise increases the speed of the breakup of pulse. Comparing with no noise, dispersive waves appear in a shorter propagation distance. Higher-order soliton splits into many fundamental solitons in the later propagation, and the noise weakens the walk-off effect of soliton,and suppresses the soliton self-frequency shift. So the moving of the pulse energy of the anomalous dispersion regime into the longer wavelength becomes weakly.