Lu Ming-Feng, Liao Shan-Mei, Huang Yang-Tung
Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 Da Hsueh Road, Hsinchu 30010, Taiwan.
Appl Opt. 2010 Feb 1;49(4):724-31. doi: 10.1364/AO.49.000724.
We propose a theoretical design for a compact photonic crystal (PC) polarization beam splitter (PBS) based on the multimode interference (MMI) effect. The size of a conventional MMI device designed by the self-imaging principle is not compact enough; therefore, we design a compact PC PBS based on the difference of the interference effect between TE and TM modes. Within the MMI coupler, the dependence of interference of modes on propagation distance is weak for a TE wave and strong for a TM wave; as a result, the length of the MMI section can be only seven lattice constants. Simulation results show that the insertion losses are 0.32 and 0.89 dB, and the extinction ratios are 14.4 and 17.5 dB for Port 1 (TE mode) and Port 2 (TM mode), respectively.
我们提出了一种基于多模干涉（MMI）效应的紧凑型光子晶体（PC）偏振分束器（PBS）的理论设计。基于自成像原理设计的传统MMI器件尺寸不够紧凑；因此，我们基于TE和TM模式干涉效应的差异设计了一种紧凑型PC PBS。在MMI耦合器中，TE波模式干涉对传播距离的依赖性较弱，而TM波的依赖性较强；因此，MMI部分的长度仅为七个晶格常数。仿真结果表明，端口1（TE模式）和端口2（TM模式）的插入损耗分别为0.32 dB和0.89 dB，消光比分别为14.4 dB和17.5 dB。
