光子晶体耦合缺陷的透射特性研究

Study on Transmission Characteristics of Coupled Photonic Crystal Defects

研究了光子晶体非线性点缺陷耦合结构的非对称透射特性.研究目的是如何提高透射率对比度.采用耦合模理论展开分析并运用基于时域有限差分技术的数值模拟验证其结果.理论分析发现,单向透射行为取决于结构的不对称和介质的非线性.因结构的不对称、光能量耦合进缺陷的程度与入射方向有关,导致透射率有差异.增加光波频率失谐δ的数值,则透射率对比度增强.当两个点缺陷耦合后,进一步提高了透射率对比度.数值模拟所得结果与理论分析一致.该结论为全光二极管的设计提供了理论依据.

The asymmetric transmission characteristics of coupled photonic crystal defects with nonlinearity are investigated. The purpose is how to improve the transmissivity contrast. The coupled-mode theories in combination with the numerical simulations based on the finite-difference time-domain technique are employed to analyze the result. Theoretical analysis showed that the unidirectional transmission behavior originates from the asymmetric configuration and nonlinear property of the medium. Because of the asymmetric structure,the light energy coupled into the defects depends on the incident direction,leading to different transmissivity. Increasing the value of light wave frequency detuning,the transmissivity contrast enhanced. In addition,the maximum transmissivity contrast is significantly improved when two defects coupling. The numerical simulation results are consistent with the theoretic analyses. The conclusion provides the reference for the design of all optical diode.