基于六角格子光子晶体波导的高效全光二极管设计

提出了一种基于六角格子光子晶体波导微腔和Fabry-Perot(FP)腔非对称耦合的全光二极管结构, 它由一个包含非线性Kerr介质的高Q值微腔与一个光子晶体波导中的FP腔组成. 通过有限时域差分方法对其传输特性进行了仿真, 发现通过两腔的非对称耦合可以实现在特定光强度下的正向传输、反向截止的功能. 在靠近微腔方向光入射时, 特定强度的光可以激发非线性微腔的Kerr效应, 改变了Fano腔的共振频率, 从而变成透射状态. 而远离微腔方向光入射, 由于这个不对称的结构造成场局域的分布不对称, 激发微腔Kerr效应的光强还不够, 所以光不能透射. 所设计的全光二极管结构具有良好的性能参数: 最大透射率高和高透射比、光强阈值低和易于集成等.

High efficiency all-optical diode based on hexagonal lattice photonic crystal waveguide

A high efficiency all-optical diode based on 2D hexagonal lattice photonic crystal (PC) waveguide is proposed. The structure is asymmetrically coupled by a high Q factor micro-cavity-containing nonlinear Kerr medium and a F-P cavity in PC waveguide. The transmission properties are numerically investigated by finite-difference time-domain (FDTD) method. Because of interference between the two cavities, the structure can achieve the function of forward transmission and backward cut-off under a suitable light intensity. For light incidence close to the direction of micro-cavity, nonlinear Kerr effect of micro-cavity can be excited by a certain light intensity. Then the resonant frequency of Fano cavity will change and forward incidence becomes transmission from reflective state. But for light incidence away from the direction of micro-cavity, the field distribution is asymmetric due to the asymmetric structure, so backward incidence needs stronger incidence light to excite Kerr effect and keeps reflective state. This design of all-optical diode has many advantages, including high maximum transmittance, high transmittance contrast ratio, low power threshold, and ease of integration, and so on.