InGaAs/InAlAs多量子阱脊形波导及定向耦合器光波特性准矢量分析

提出了一种基于级数展开的三维准矢量束传播法(SE-QV-BPM)用以分析由InGaAs/InAlAs多量子阱构成的脊形光波导及定向耦合器.结果表明，刻蚀深度相同时，TM模比TE模在水平方向限制强，且TM模的模场在波导角上出现畸变；波导间距相同时，定向耦合器TM波的耦合长度大于TE波的耦合长度，对偏振态敏感.分析获得了浅/深刻脊形光波导承载的准矢量TE/TM基模、定向耦合器承载的TE/TM偶/奇模的模场分布及其有效折射率，模拟了光场在定向耦合器中的传输演变情况.另外，SE-QV-BPM导出矩阵小，计算效率高 关键词： 级数展开 准矢量束传播法 多量子阱 InGaAs/InAlAs

Quasi-vectorial analysis of the optical characteristics of rib waveguides and directional couplers based on InGaAs/InAlAs multiple quantum wells

A new three-dimensional quasi-vectorial beam propagation method based on the series expansion (SE-QV-BPM) is proposed for simulating the optical rib waveguide and directional coupler based on InGaAs/InAlAs multiple quantum wells. For the same etched-depth, the confinement of TM mode in horizontal direction is shown to be stronger than that of TE mode, and the singular behaviors for TM modes at the corners are clearly observed. For the same gap width, the coupling length of TM mode for directional coupler is larger than that of TE mode. The effective indices and modal profiles of the quasi-vectorial fundamental TE and TM modes for shallow- and deep-etched rib waveguides and directional couplers are obtained. Besides, the evolution of the injected field with propagation distance through the directional coupler is demonstrated. The calculation has good efficiency due to the small size of the resulting matrix, and the rib structures can be conveniently dealt with since the sinusoidal functions are selected as the basis functions. Moreover, the variable transformation is introduced to avoid the boundary truncation.