GaAs半导体激光器线宽展宽因子的理论计算

Theoretical Calculation of Linewidth Enhancement Factor in GaAs Semiconductor Lasers

本文利用简单模型综合考虑了带间跃迁、自由载流子吸收和带隙收缩对半导体激光器线宽展宽因子的影响,给出了半导体激光器线宽展宽因子的一种较为简便的计算方法.首先从理论上推导出线宽展宽因子的计算公式,分析并计算了GaAs半导体激光器的增益特性,并使用MATLAB软件中的Mupad工具包求解费米积分的数值解.然后根据得到的增益拟合曲线峰值的变化计算了带间跃迁对线宽展宽因子的影响.最后,分别讨论和计算了自由载流子吸收和带隙收缩对线宽展宽因子的影响.结果表明,带间跃迁和带隙收缩对线宽展宽因子的影响较大(α因子值分别为22.562,-6.853),而自由载流子吸收对线宽展宽因子的影响较小(只有-0.605).

The effects of interband transition,free carrier absorption and bandgap narrowing on linewidth enhancement factor（α factor） in semiconductor lasers were comprehensively considered in a simple model.A convenient calculation method of α factor in semiconductor lasers was presented.The formula for α factor was derived at first,the gain of GaAs semiconductor lasers was theoretically analyzed and calculated,and the process of solving the Fermi integral function by taking advantage of the Mupad notebook in MATLAB software was introduced.Further,the effect of interband transition on α factor was calculated based on the peak variation of gain fitting curves.Finally,both the effects of free carrier absorption and bandgap narrowing on α factor were disscused,respectively,and their values were obtained.The results show that interband transition and bandgap narrowing have more obvious effects on α factor in semiconductor lasers（α factor are 22.562 and-6.853,respectively） than the effect of free carrier absorption（α factor is only-0.605）.