新型单模半导体激光器实验教学中的关键基础问题讨论

Discussion of Key Fundamental Topic in Experimental Teaching Based on a Novel Single-mode Semiconductor Laser

半导体激光技术是光学工程硕士研究生的核心专业课程,在掌握激光原理的理论基础知识之上,进行实验研究是十分关键的一个环节,而在半导体激光器的研究与开发中,单模法布里-珀罗半导体激光器是最近几年才发展起来的一种新型结构的激光器。笔者对此新型单模半导体激光器件的基本结构和工作原理做介绍,多模激光器在内置反馈外腔的作用下,由于强烈的模式竞争,很容易实现激光器输出具有较高边摸抑制比的单模激光谱,输出的单模激光随激光器操作温度发生漂移。对学生在实验研究过程所遇到的注入锁定行为的关键物理问题做详细的探索性分析和讲解。注入功率和波长失谐是促使激光器发生注入锁定行为的2个重要参数,随波长失谐的增加,使激光器发生注入锁定行为的阈值功率也将被提高,注入功率越高,使激光器发生锁定行为的波长失谐范围也越大。

Semiconductor laser technology is a special core curriculum of optics and optical engineering in our university. Based on the theoretical fundamental knowledge, experimental research is a very key link. However, in the research and exploitation of semicon- ductor laser, single-mode Fabry-Perot semiconductor laser with a novel structure has been developed in recent years. Firstly, basic structure and working principle oi this novel single-mode semiconductor laser is introduced. Because of strong mode competition, single mode laser spectrum with high side-mode suppression ratio （SMSR） is easily achieved based on the multi-mode laser using a built-in feedback external cavity, which is shifted with change of operation temperature. And then, injection locking behavior as a key physical mechanism that is referred for students in experiment is analyzed and discussed in detail in this paper. Both injection power and wavelength detuning are two important parameters to cause the injection locking. As the wavelength detuning is in- creased, the required threshold power for injection locking is also enhanced. The wavelength detuning range for injection locking is extended in the case of high injection power.