高效二维光子晶体偏振光分束器的设计

DESIGN OF EFFICIENT TWO-DIMENSION PHOTONIC CRYSTAL POLARIZATION BEAM SPLITTER

基于光子晶体线缺陷波导在不同偏振模式下的色散特性差异,提出了一种偏振光分束器的设计方法,利用具有完全禁带的二维三角晶格光子晶体,通过增大线缺陷波导侧边空气柱的半径,得到仅能传输单一偏振模式的单模光波导,并结合微腔与波导间的共振耦合原理设计了一种高效的偏振分束器。用时域有限差分法模拟了偏振分束器的传输特性,结果表明,当归一化频率为0.3654的光入射时,偏振分束器能够高效率大角度分离TM和TE两种不同模式的偏振光,且TM模与TE模输出光的偏振消光比分别为28.9dB和32.7dB,器件尺寸为20.4μm×12.3μm,该设计在未来集成光回路中有着很大的应用潜力。

A method for designing the photonic crystal polarization beam splitters put forward based on the difference of dispersion characteristics of photonic crystal line defect waveguide in different polarization modes. The line wave guides composed of the two-dimension triangle lattice photonic crystal with the complete photonic band gap. Only one polarization mode light can propagate in the wave guide by increasing the sizes of air holes that are adjacent to the wave guide. An efficient photonic crystal polarization beam splitter is design based the resonant coupling principle of the micro-cavity combined with the wave guide using only one polarization mode waveguide. The transmission character is simulated by using the finite difference time domain method. The results indicate that the polarization beam splitter can separate TM mode from TE mode effectively with a large angle when the normalized frequency of the incident lightwave is 0.3654. The polarization extinction ratio of TM mode and TE mode output light is 28.9dB and 32.7dB respectively. The device size is 20.4μm×12.3μm. The design has a great potential application in the future integrated optical circuit.