降低VCSELs激射阈值途径的理论研究

Study on Decreasing Threshold Current Density of VCSELs

针对量子阱有源层的结构特点 ,考虑增益和载流子浓度呈对数关系 ,建立量子阱垂直腔面发射半导体激光器 (VCSEL )的速率方程 ,导出了阈值电流密度的解析表达式。运用 MATL AB软件中 Simulink可视化仿真系统对理论计算进行模拟仿真 ,研究了降低 VCSEL 激射阈值的 3个基本途径 :有源层选用量子阱实现微腔结构 ;腔面采取多层介质反射膜提高光腔反射率 R;改进外延生长技术以降低各种损耗。

Based on changing the logarithmic relation of gain on carrier density, the rate equations are described for multi-quantum well of vertical cavity surface emitting lasers (VCSELs). On the basis of the rate equations for quantum well VCSELs, an analytic resolution of the threshold current density is obtained. The theoretic results are simulated with Simulink of MATLAB software. There are three ways to reduce the threshold current of VCSELs: using quantum well material as the active medium to provide micro-cavity's structure; using multilayer medium as the facets to increases the reflectivity; improving epitaxy technique to reduce loss.