Implementation of thermo-optic waveguide photonics switch using polymer material

Abstract

This paper describes thermo-optic waveguide photonics switch using all polymer material. The design is based on the theory of optical waveguide as the key element and the thermal analysis for heater electrodes and heater pads. The basic structure of 2×2 directional coupler based was chosen as a switching element since it comprises of straight and bend waveguides which are the key element in any development of waveguide based photonics switch. The temperature profiles of thermo-optic polymer waveguides are analyzed by inverse discrete Fourier transform method. The resulting phase shift due to the induced temperature as a function of the thin film heater and the applied power have been studied and determined for device implementation between two adjacent polymer waveguides. The coupling length variation as a function of waveguide dimension, waveguide gap and effective refractive index difference had been discussed thoroughly. The position of the heater electrode, which maximizes the effective refractive index difference between branches have been optimized based on the thermal analysis. The index contrast of the upper cladding layer and the waveguiding layer is 0.03. The index contrast of the lateral section of the waveguiding region and lower cladding layer is 0.005. The asymmetrical fabricated switch exhibits very low switching power of 12.26 mW. Crosstalk level of -40 dB and -37 dB for the cross state and the bar state have been achieved, respectively and the response time measured is 7 ms.