变耦合系数非线性三波导定向耦合器特性研究

报道了对高斯型及指数型变耦合系数三波导耦合器的一些重要的全光开关特性进行的研究。利用四阶龙格一库塔方法对指数型和高斯型两类变耦合系数三波导耦合器进行了数值计算。数值计算结果表明：对于变耦合系数三波导耦合器而言，功率可在波导1与波导3之间100％转换，而波导2则不可能达到100％的功率输出。与双波导变耦合系数耦合器相比，在相同的最大耦合系数情况下三波导变耦合系数耦合器开关曲线要更陡一些．即具有更好的开关特性。与平行三波导耦合器相比，变耦合系数三波导耦合器作为光开关的最大优点在于开关曲线中不存在振荡。

Switching Characteristics of Three-Core Nonlinear Directional Couplers with Variable Coupling Coefficient

Theall-optical switching characteristics of three-core nonlinear directional waveguide couplers (NLDCs) with Gaussian type and exponential type variable coupling coefficient (VCC) are presented. Their transmission features are investigated numerically. It is shown that, for the three-core VCC NLDCs, the power can switch completely between guide 1 and guide 3; however 100% power output cannot be achieved for guide 2. The switching curves of three-core NLDCs with VCC are sharper than those of their two-core counterparts with same maximum coupling coefficient. It is also shown that the sidelobes in the post-switching region, which exist in the parallel nonlinear directional couplers, can be suppressed with three-core NLDC with VCC.