Xu Yanping, Zhang Mingjiang, Zhang Liang, Lu Ping, Mihailov Stephen, Bao Xiaoyi
Opt Lett. 2017 Oct 15;42(20):4107-4110. doi: 10.1364/OL.42.004107.
We demonstrate that a semiconductor laser perturbed by distributed feedback with random time delays from a large number of scattering centers along a fiber random grating can emit light chaotically without the time-delay signature (TDS). A theoretical model is developed based on the modified Lang-Kobayashi model to numerically explore the chaotic dynamics of the laser diode subjected to random feedback. It is predicted that the random distributed feedback destroys the phase-correlated mode condition and hence suppresses the TDS. The fiber random grating is fabricated with random index modulation periods through point-by-point inscription, which introduces large numbers of phase-uncorrelated cavity modes into the semiconductor laser, leading to high dimensional chaotic dynamics and thus the concealment of the TDS. The experimentally obtained TDS value is negligible with a minimum of 0.0088, which is the smallest to date.
我们证明，沿光纤随机光栅分布的大量散射中心产生的具有随机时间延迟的分布反馈所扰动的半导体激光器，能够在没有时间延迟特征（TDS）的情况下产生混沌光。基于改进的朗-小林模型建立了一个理论模型，以数值方式探究受随机反馈影响的激光二极管的混沌动力学。据预测，随机分布反馈会破坏相位相关模式条件，从而抑制TDS。通过逐点写入具有随机折射率调制周期的光纤随机光栅，将大量相位不相关的腔模引入半导体激光器，导致高维混沌动力学，进而隐藏了TDS。实验获得的TDS值可忽略不计，最小值为0.0088，这是迄今为止最小的。
