全硅光子晶体波导中二次谐波产生及影响因素

Second Harmonic Generation and Effect Factors in Silica Photonic Crystal Waveguide

硅材料是半导体微细加工工艺中的常用材料,属于m3m对称点群,通常无法实现二次谐波产生,导致光子系统芯片中的非线性纰件集成困难。提出一种在硅材料中可以实现二次谐波产生光子晶体波导结构。首先给出该波导结构的组成及其基本原理,然后讨论谐波产生的计算模型和计算方法,最后给出针对10.6μm波长而设计的全硅二维光子晶体波导具体结构参数,以有限时域差分算法为基础,计算分析了谐波产生情况。研究结果表明:该结构利用光子晶体带隙边缘效应增强了硅材料的电四极极化强度从而实现二次谐波产生,在完全相位匹配条件下,当抽运波强度为1.3 MW/mm^2时,转换效率为0.2%。最后,对影响谐波转换效率的因素进行了初步分析。

Silicon is one of important semiconductor materials in micro-fabrication technology. However it belongs to m3m point group, there is no second harmonic generation （SHG） in it. This is an obstacle for the integration of nonlinear micro-structures in optical system on chip. We present the silicon waveguide structure based on photonic crystals to realize SHG and overcome the technology bottle-neck. The configuration of waveguides and the basic principle are put forward. The computation model and methods based on finite difference time domain （FDTD） are given. Finally we present a design result aimed at the wavelength of 10.6μm and analyze the SHG. The results show the enhancing electric quadrupole polarization leads to the SHG in silicon by virtue of photonic band edge effect. Under the condition of perfect phase matching, the conversion efficiency is 0. 2% at the pumping power of 1.3 MW/mm^2. At the end, effect factors of conversion efficiency are discussed briefly.