DFB半导体激光器中增益耦合型光栅结构的优化

摘要

Distributed Feedback (DFB)semiconductor lasers have the advantages of simple structure and stable spectrum, which have been widely used in optical communication field.DFB lasers in the high current conditions are prone to space burn-ing hole effect,which will lead to single-mode characteristics of instability.In order to suppress the effect of space burning, this paper uses three-phase shift and CPM-DCC grating structure combined with Corrugation-Pitch-Modulation (CPM)and Distributed-Coupling-Coefficient (DCC).The coefficients are optimized.On the one hand,theoretically,the optimal value of the gain coupling coefficient is deduced.On the other hand,the correctness of the theory and the simulation are proved from the simulation and experiment.The results show that the threshold current of DFB laser is about 11 mA,and the side mode re-jection ratio is 41 dB,which significantly suppresses the effect of space burning hole and greatly improves the linearity of laser array.%分布反馈(DFB)半导体激光器具有结构简单、频谱稳定等优点,在光通信领域具有十分广泛的应用.DFB激光器在大电流条件下容易产生空间烧孔效应,会导致单模特性不稳定.为了抑制空间烧孔效应,文章采用三相移以及节距调节(CPM)与分布耦合系数(DCC)相结合的CPM-DCC光栅结构对增益耦合系数进行优化.一方面从理论上进行分析,推导出了增益耦合系数的最优值;另一方面从仿真和实验上验证了理论的正确性.结果表明,DFB激光器的阈值电流约为11 mA,边模抑制比达到41 dB,显著抑制了空间烧孔效应,极大地提高了激光器阵列的线性指标.