Gain nonlinearities in semiconductor lasers: Theory and application to distributed feedback lasers
Gain nonlinearities in semiconductor lasers: Theory and application to distributed feedback lasers
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DOI：
10.1109/jqe.1987.1073406
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发表时间：
1987-06
影响因子：
2.5
通讯作者：
G. Agrawal
中科院分区：
文献类型：
--
作者：
G. Agrawal
半导体激光器的增益谱受载流子带内弛豫时间有限所引起的强度相关非线性效应的影响。利用密度矩阵的形式，得到了多模半导体激光器非线性增益的解析表达式。一般来说，非线性增益由对称和非对称分量组成。这种不对称并非源于载波诱导的折射率变化，而是与增益谱的细节有关。利用非线性增益的一般表达式，讨论了分布反馈激光器的单纵模工作范围。本文还对GaAs和InGaAsP激光器的自饱和系数给出了解析表达式，并将预测值与实验值进行了比较。理论值与实验值的一致支持了光谱孔燃烧是半导体激光器增益非线性的主要机制的假设。
The gain spectrum in semiconductor lasers is affected by the intensity-dependent nonlinear effects taking place due to a finite intraband relaxation time of charge carriers. We obtain an analytic expression for the nonlinear gain in multimode semiconductor lasers using the density-matrix formalism. In general, the nonlinear gain is found to consist of the symmetric and asymmetric components. The asymmetry does not have its origin in the carrier-induced index change, but is related to details of the gain spectrum. The general expression for the nonlinear gain is used to discuss the range of single-longitudinal-mode operation of distributed feedback lasers. It is also used to obtain an analytic expression for the self-saturation coefficient and to compare the predicted value to the experimental value for both GaAs and InGaAsP lasers. The agreement between the theoretical and the experimental values supports the hypothesis that spectral hole burning is the dominant mechanism for the gain nonlinearities in semiconductor lasers.