通过构建外部光反馈半导体激光器的理论模型, 并结合激光器速率方程和噪声理论, 讨论并优化了增益芯片和光纤光栅外腔各参数在不同电流下对器件频率噪声和相对强度噪声的影响。模拟结果表明: 通过改变电流并对有源区尺寸、光纤光栅结构和耦合效率等参数的调整, 在理论上可以将器件的频率噪声降低5×108Hz左右, 相对强度噪声降低8dB/Hz左右。该研究将为低噪声、窄线宽外部光反馈激光器的实验研究提供理论指导, 同时也对其他结构的外腔激光器噪声特性的研究有着借鉴意义。

Through establishing a theoretical model of the external optical feedback semiconductor laser and combining the laser rate equation and noise theory, the influences of gain chip parameters and fiber Bragg grating parameters on the frequency noise and relative intensity noise of the laser under different injection current are discussed and optimized in this paper. The simulation results indicated that by changing the injection current and adjusting the size of active region, the structure of fiber Bragg grating and coupling coefficient, the frequency noise of the laser could be decreased about 5×108Hz and the relative intensity noise of the laser could be decreased about 8dB/Hz in theory. The result obtained in this work can provide a theoretical guidance for the experimental study of the external optical feedback laser with low noise and narrow line-width, and it has reference significances to the study of the noise characteristics of other external cavity lasers.