单模光纤中啁啾脉冲的分裂机制

采用分步傅里叶算法数值求解非线性薛定谔方程,分析了单模光纤中不同情形下皮秒量级啁啾脉冲的分裂机制。结果表明,对于较短的脉冲(10 ps),啁啾脉冲分裂从高阶孤子压缩导致的脉冲塌陷开始;对于较长的脉冲(200 ps),脉冲分裂主要由调制不稳定性导致;对于介于两者之间的脉冲(50 ps),噪声使得脉冲分裂机制从高阶孤子压缩转向调制不稳定性。初始正、负啁啾能分别加速和延缓短脉冲分裂,而初始啁啾对长脉冲分裂影响很小。初始啁啾对脉冲分裂的影响与其分裂机制密切相关。

Breakup Mechanisms for Chirped Pulse in the Single-Mode Fibers

Breakup mechanisms for chirped picosecond pulse in the single-mode fibers are numerically analyzed through solving nonlinear Schrdinger equation by the standard split-step Fourier method. The results show that, the breakup of shorter chirped pulse (10 ps) is caused by pulse collapse due to the high-order soliton compression, while the breakup of longer chirped pulse (200 ps) is caused by the nonlinear amplification of noise due to the modulation instability. For chirped pulse of intermediate durations (50 ps), its breakup is caused by modulation instability instead of high-order soliton compression due to the role of noise. Initial positive and negative chirps can speed and slow down the process of shorter pulse breakup, respectively. However, the initial chirp has little influence on the breakup of longer pulses. The effect of initial chirp on pulse breakup is closely related to the breakup mechanisms for pulse.