摘要
We numerically investigate the coupling of TE-like modes and TM-like modes in a two-dimensional （2D） photonic crystal （PC） slab composed of truncated cone silicon rods. In such structures, the classification of TE-like modes and TM-like modes is generally impossible and the coupling occurs due to vertical structural asymmetries. The frequency and wavevector dependences of the mode coupling are discussed by investigating the photonic band structures, and the coupling efficiency is studied by examining the transmittance. The results show that the efficiency of mode conversion is strengthened by the vertical asymmetry and weakened by the clear sinall gap. These structures could be used as polarization conversion devices in integrated optics.
We numerically investigate the coupling of TE-like modes and TM-like modes in a two-dimensional （2D） photonic crystal （PC） slab composed of truncated cone silicon rods. In such structures, the classification of TE-like modes and TM-like modes is generally impossible and the coupling occurs due to vertical structural asymmetries. The frequency and wavevector dependences of the mode coupling are discussed by investigating the photonic band structures, and the coupling efficiency is studied by examining the transmittance. The results show that the efficiency of mode conversion is strengthened by the vertical asymmetry and weakened by the clear sinall gap. These structures could be used as polarization conversion devices in integrated optics.
基金
Support by the National Natural Science Foundation of China under Grant No 10525419, and the National Key Basic Research Programme of China under Grant No 2006CB921702.
