应用左手介质光子晶体实现光波单向传输的理论研究

Optical isolator is the key component of the laser stable operation system, which can prevent external reflected light and allows the light to transmit in unidirection. Currently, the unidirectional transmission of light mainly utilizes the rotation effect (Faraday effect) of magneto-optical materials. It has been found that, propagation of light can be controlled unidirectionlly in the photonic crystal containing magneto-optical material or nonlinear material, and the size of the structure can be reduced to several micrometers. However, the magneto-optical material is sensitive to the external temperature and the magnetic field, and the nonlinear effect of nonlinear material can not be utilized to realize optical isolating at low power level. Fortunately, left-handed material(LHM), made of arranging isotropic spheres of nanoscale, is insensitnve to the outside temperature, magnetic field and the power of the incident light. Therefore, in this project we propose a photonic crystal structure consisting of LHM to achieve unidirectional transmission of light. In order to make certain the dependency of the unidirectional transmission of light on the the structure parameters, characteristic parameters of the LHM and the structural parameters of the photonic crystal, the propagation of light through the photonic crystal will be calculated and simulated theoretically. As a result, we expect to provide a new direction to realize the optical isolator integration by utilizing the photonic crystal containing LHM.

光隔离器是防止外部反射光影响激光系统稳定运行的关键器件，特点是只允许光波单向传输。目前实现光波单向传输主要是利用磁光材料的旋光效应。研究发现，嵌入磁光材料或非线性材料的光子晶体具有控制光波单向传输功能，且尺寸可缩小至几微米。但是前者易受外界温度和磁场的影响，后者则要求较高的光功率产生非线性效应实现光波单向传输。本项目拟提出一种在光子晶体中嵌入左手介质实现光波单向传输的设计思路，左手介质可通过各向同性的纳米球排列构成，尺寸可达纳米量级，且不受外界温度、磁场和入射光功率的影响。本项目拟从理论上分析和模拟计算左手介质光子晶体实现光波单向传输的特性，建立左手介质的结构参数、特征参数和光子晶体的结构参数与左手介质光子晶体实现光波单向传输之间的关系，为光隔离器实现集成化提供一种潜在的新方案。

本项目提出一种在光子晶体中嵌入左手介质实现光波单向传输的设计思路，来解决现有实现光波单向传输中受外界温度、磁场和入射光功率影响的问题。按照原定研究计划，我们主要对左手介质光子晶体的单向传输特性进行了研究：在设计出光子禁带覆盖中心波长为1550nm的光通信波长的一维光子晶体结构之后，利用传输矩阵法研究了一维左手介质光子晶体的单向传输特性，分析了一维左手介质光子晶体的结构参数对光单向传输的影响；研究了二维光子晶体结构在光通信波段的禁带，开始利用R矩阵法研究二维左手介质光子晶体的单向传输特性。并在一维磁光子晶体的光波单向传输特性和二维光子晶体结构在光通信波段的禁带研究方面取得了一些进展：设计出2个可在中心波长附近小范围内实现光波单向传输的一维磁光子晶体结构和4个可实现宽带光波单向传输的一维磁光子晶体结构；设计出一种Y型光子晶体偏振光分束器和一种高效光子晶体偏振光分束器。