基于扩展的自旋反转模型,对短外腔偏振旋转光反馈下1550 nm垂直腔面发射激光器的动力学特性进行了数值仿真和理论分析.研究结果表明:增加反馈强度会导致多个偏振开关现象出现,中等反馈强度下呈现丰富的动力学状态,譬如单周期、倍周期、准周期及混沌态,增加注入电流使Y方向线偏振模的工作区域被压缩;随着反馈延迟时间的增加,在弱光反馈时,偏振模跳变现象将会以特定的频率发生,施加中等的反馈强度将会导致模式跳变的频率增加,并且出现各种新的动力学状态,包括拍频单周期、拍频脉冲包络、拍频准周期和拍频混沌态.新动力学行为的出现是由于短外腔区激光器的动力学特性对相位变化非常敏感,从而使外腔模式间的拍频效应发挥了关键作用.此外还发现各种动力学状态之间会伴随模式间的跳变而发生相互跳变.
Based on the extended spin-fip model(SFM),we investigate theoretically the dynamic characteristics of 1550nm vertical-cavity surface-emitting laser subject to polarization-rotated optical feedback:the short cavity regime.Results show that increasing the feedback strength will result in multiple polarization switching(PS) phenomena,and there will appear rich dynamics under the condition of medium feedback intensity,such as single period,period-doubling,quasi-periodic and chaotic states.At the same time,the increase of injection current will result in the reduction of working area of Y direction polarization mode.As the feedback delay time increases,under the condition of weak optical feedback polarization mode,the hopping phenomenon will take place at a particular frequency;the frequency of mode hopping will increase with the increase of moderate feedback strength,and the laser shows a variety of new dynamic characteristics,such as single period,pulse envelope,quasi-periodic and chaotic states,by taking a beat frequency signal.These dynamic characteristics are very sensitive to the phase change so the beat frequency efect between external cavity modes plays a key role.In addition,the hopping phenomenon between various dynamic states can also be found along with the mode hopping.