AI-Enabled Optical Inspection of Microoptics Integration with Photonic MEMS Chips for Wideband FTIR Spectroscopy

Photonic MEMS has been proven to be a robust optical platform for sensing applications. This requires co-integration of the MEMS and off-axis all-reflective microoptics (MO) in a system in a package (SiP) manner [1]. A Michelson interferometer on an SOI chip enabling FTIR spectroscopy has been reported for a spectral range of 1.8 μm to 6.8 μm [2]. As shown in Fig. 1(a), the interferometer is excited by the wideband light coupled through the MO while the moving mirror of the interferometer is displaced by the MEMS actuator. The output is coupled through the MO to the photodetector that produces the interferometric signal that is Fourier transformed to get the spectrum of the light. This work considers the inspection of the macroscopic quality of the MO, its integration into the SiP and the relation with the production of the interferometric signal.