实验和数值模拟了外部光反馈作用下分布反馈半导体激光器(DFB-SL)的各种非线性动力学行为。实验结果表明,在不同的反馈强度下,DFB-SL输出呈现出稳态、单周期、倍周期、多周期等多种非线性动力学动态行为。当处于一系列周期态时,激光器的输出光谱、频谱呈现强烈特征频率峰,且背景噪声极低。当外部光反馈达到一定强度后,激光器各模式发生激烈的相互作用而导致相干崩塌,激光器输出光谱、频谱演化为连续谱,并最终实验获得谱宽达10 GHz的宽谱混沌。对相关实验进行了数值模拟,计算结果与实验结论基本符合,均表明反馈强度是控制DFB-SL处于不同非线性动力学态的一个关键参量。

Different nonlinear dynamic behaviors of the distributed feedback semiconductor laser (DFB-SL) subjected to external optical feedback have been investigated experimentally and theoretically. The experimental results show that DFB-SL can exhibit rich nonlinear dynamic behaviors such as stable state,one-period,double-period,multi-period and chaos under different feedback strengths. For the laser operating at the series of periodic states,there are obvious characteristic frequency peaks in corresponding optical spectra and power spectra while the background noise is very low. Moreover,after increasing the feedback strength to a certain level,the coherence collapse will happen due to the strong mode competition of DFB-SL,and 10 GHz broadband chaos can be obtained experimentally. In addition,the numerical simulations are executed,and the results agree well with the experimental observations. The simulations also indicate that the feedback strength is a key parameter for controlling nonlinear dynamic behaviors of DFB-SL.