分布反馈半导体激光器频率调制特性的速率方程分析

Rate equation analysis of FM response of distributed feedback (DFB) semiconductor laser

本文引入描述分布反馈半导体激光器中光场纵向分布不均匀对其阈值条件影响的α_p和δ_p因子.建立了包含空间烧孔效应的速率方程模型,并给出小信号强度、频率调制响应表达式.数值求解理想分布反馈半导体激光器的α_(th)L和δL随平均光子密度变化曲线及对应的α_p和δ_p因子.数值模拟表明,空间烧孔对调制特性影响甚大,频率调制相应与偏置电流有关,为得到较宽的调制频带必须适当选择工作点.

In this paper the factors of αp and δp are introduced to describe the effects of optical field longitudinal nonunlformity on threshold conditions. The rate equation model including spatial hole burning is established, and the expression of IM and FM response within small signal approximation are derived. The relationships between threshold condition of ideal DPB laser diodes and the average photon density in laser cavity are obtained numerically. The numerical analysis show that spatial hole burning affects the modulation properties greatly, and FM reponse depends on the bais current. In order to get wider modulation band width proper bais injection current should be chosen.