This paper presents a theoretical study on the generation of optical frequency combs (OFCs) using direct modulation of semiconductor laser. Influence of gain suppression on characteristics of the generated OFCs is investigated. The study includes intensive and comprehensive investigations of the temporal and spectral characteristics of the generated OFCs as a function of the gain suppression over a wide range of the bias current. We report on generation of short optical pulses and large numbers of comb lines with low-power flatness under weak gain suppression and/or strong modulation depth when the laser is biased near the threshold. The influence of gain suppression becomes more robust when the laser is biased far above threshold. By adopting the operating parameters, we predict pulses with 60 ps width and 10 comb lines with 2.1 dB flatness when the gain suppression is ignored. Under strong gain suppression, broader pulses (132 ps width) and only five lines with higher flatness of 4.99 dB could be obtained.

本文介绍了使用半导体激光器直接调制产生光频梳（OFC）的理论研究。研究了增益抑制对生成的 OFC 特性的影响。该研究包括对生成的 OFC 的时间和光谱特性进行深入和全面的研究，作为在宽偏置电流范围内的增益抑制的函数。我们报告了当激光在阈值附近偏置时在弱增益抑制和/或强调制深度下产生短光脉冲和大量低功率平坦度的梳状线。当激光器偏置远高于阈值时，增益抑制的影响变得更加强大。通过采用操作参数，我们预测宽度为 60 ps 的脉冲和 10 条梳状线为 2。忽略增益抑制时为 1 dB 平坦度。在强增益抑制下，可以获得更宽的脉冲（132 ps 宽度），并且只能获得 5 条具有 4.99 dB 更高平坦度的线。