Integrated optical Mach-Zehnder on SU-8 polymer for designing thermal sensors

A new approach to designing heat sensors is presented. The basic principle relies on the differential thermal behavior regarding both active arms of a micro Mach-Zehnder interferometer (MZI). Based on modeling results, an experimental sensor is realised as an integrated device made up of SU-8 polymer mounted on a standard silicon wafer. When subjected to a radiant source, such as laser light (980 nm), injected across the cleaved input face of the MZI, the significant change of output signal allows us to consider a new approach to measuring radiant heat flow rate. Experimental results are given regarding the obtained phase shift against the subjected thermal power. According to the modeling results, one can expect new highly sensitive devices to be developed in the next coming years, with numerous prospective industrial applications.