Design and simulation of integrated optical interferometers fabricated in polymer foils

Abstract

Integrated optical Mach-Zehnder interferometers (MZI) can be used as high sensitivity sensors through the interaction of the evanescent field of the waveguide with liquids or gases surrounding the sensor. We present here the design of polymer-based MZIs fabricated by hot-embossing and printing technologies. Simulations of an integrated MZI system with regard to variations of the waveguide cross-section and the refractive indices of the core layer are carried out to guarantee single mode behavior and optimize high sensitivity to external refractive index changes of analytes. The simulation of propagation losses induced by the Y-coupleres is also presented. Furthermore, transmission as a function of different interaction window lengths are also simulated on the entire MZI structure using a mixture of water and ethanol as an analyte on the sensing arm. Finally, we calculate the coupling efficiency of a laser diode into a tapered waveguide and estimate that a value of 30% is possible.