Thermal stability analysis of nonlinear optical switch based on asymmetric three-core nonlinear directional coupler with variable Gaussian coupling coefficient

We analyze the thermal stability of the power transmission efficiency and the extinction ratio in an asymmetric three-core silicon-on-insulator nonlinear directional coupler with variable Gaussian coupling coefficient. Because the refractive indices of Si and SiO(2) materials are subject to temperature change, the effective refractive index of the nonlinear coupler varies correspondingly. When ratio (L(C)/b) and Delta T change, the relative transmission efficiency error (Delta) values and relative change of extinction ratio (eta) values are obtained. It can be easily shown that variation of Delta and eta are negligible under L(C)/b <= 1/2. Therefore, we can set L(C)/b <= 1/2 and Lambda T is an element of [-100 K, 100 K] in order to make the power transmission efficiency and the extinction ratio work steadily. This is significant in guiding an actual nonlinear optical pulse switch fabrication. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3558853]