Integrated Mach-Zehnder interferometer on SU-8 polymer for designing pressure sensors

This paper describes a new integrated pressure sensor based on a Mach-Zehnder (MZ) interferometer made of SU-8 polymer. Such a device is designed with a view to working in a standard intensity modulation scheme. To this end, the device takes advantage of a differential measurement thanks to a sensing arm of the MZ structure arranged upon a thin membrane actuated by the pressure to be dealt with, while the second arm allows for a reference signal. The combination of both signals out of the optimized structure of the interferometer allows us to detect any change in the optical path as a result of the applied pressure. A prototype is characterized by way of a specific optical bench allowing an efficient end-fire coupling into the sensor. Practical results prove such a design to delineate a promising measurement approach.