title: Beam expansion in thermo-optic-effect-induced total internal reflection and its applications in optical switches.
abstract: The beam-propagation characteristics of the total internal reflection (TIR) induced by the thermo-optic effect are investigated. Based on the Fourier heat-transmission principle and the variable separation method, we derive an analytical transient expression of the thermal field for general thermo-optic devices. With the analytical expression, the time response and steady-state temperature distribution of thermo-optic devices are presented. The beam expansion rule of TIR in the thermal field is developed mathematically, and a quantitative calculation is given as well. To illustrate the application of the rule, an X-junction 2 x 2 TIR switch with high reflection efficiency is designed through theoretical calculation. The simulation shows that the structure exhibits a high reflection coefficient; the reflection loss is only -0.76 dB. The simulation results agree well with the theoretical calculation.
authors.affiliation: Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yu
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Jiang
authors.forename: Jianyi
authors.initials: J
authors.lastname: Yang
authors.forename: Xihua
authors.initials: X
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
authors.forename: Minghua
authors.initials: M
authors.lastname: Wang