Spatial beam splitting for fully integrated MEMSinterferometer

Abstract

In this paper, we propose a novel design of Micro-Electro-Mechanical System “MEMS” based Fourier transform spectrometer. This design is based on spatial truncation of the input Gaussian beam into two symmetric semi-Gaussian beams using V shape mirror. The design is fully integrated and can operate in the Infrared and visible region. The analysis shows that, a minimum resolution of 9nm at wavelength 1.45μm and mechanical displacement of 160μm is achievable. Unlike the traditional Michelson interferometer which returns half of the optical power to the source, this design uses the full optical power to get one original and two complementary interferograms. Here, analytical model that describes the beams propagation and interference is derived using Fourier optics techniques and verified using Finite Difference Time Domain (FDTD) method. Then, a mechanical model that describes the mirror displacement to produce optical path difference is derived and verified using finite element method (FEM). Finally, the effect of different design parameters on the interference pattern, interferograme and resolution are alsoshown.