Modeling of photonic MEMS Michelson interferometers comprising curved micromirrors under partially coherent light excitation

Photonic MEMS interferometers are proving to be strong candidates for compact miniaturized spectrometers. In this work, a 2 mm x 2 mm MEMS-based Michelson interferometer, composed of a thin beam splitter, one fixed mirror, and one moving mirror, is designed and analyzed using Fourier optics propagation techniques and partial coherent source excitation. The model takes into consideration light divergence effects and beam truncation due to the limited dimensions of the device mirrors and beam splitter. The elementary source model is used to represent a partially coherent light source that is typically used in infrared spectroscopy applications. Flat micromirrors are compared to curved ones to explore the possible performance enhancements of the interferometer yielding an improvement of more than two times in the device optical throughput, which typically limits the performance of MEMS devices when dealing with light bulbs sources.