Temperature dependence of the optical nonlinear waveguide sensor on thermal stress effects

Abstract

A theoretical approach to study the influence of temperature stress of the thermal sensitivity of the effective refractive index for asymmetrical nonlinear optical waveguides is developed. The structure of the waveguide sensor consists of thin film surrounded by nonlinear cladding and linear substrate. In the proposed waveguide sensor, temperature stress is induced due to the different thermal expansion coefficients of the substrate, core and cladding. Numerical calculation is carried out to draw the thermal sensitivities of effective refractive indices against the core thickness for both transverse electric modes (TE) and transverse magnetic modes (TM). The relation between thermal sensitivities and different temperature stress gradient is derived and plotted. Based on the results, thermal sensitivity of the sensor can be controlled by temperature stresses which can be controlled by carefully picking the materials and loading methods. Keywords: temperature sensitivity, stress, nonlinear waveguide, thermal stress, optical parameters, sensor