Innovative monolithic integrated optic SWIR SWIFTS without lens between unprotected InGaAs area image sensor and optical glass chip surface

A complete monolithic spectrometer device in the short wave infrared using integrated waveguide technology on a glass chip (i.e., without any optical lens interposer) is presented. It is based on stationary wave integrated Fourier transform spectrometer (SWIFTS) technology. The spectrometer achieves a spectral resolution of less than 300 pm for only a 2560 μm waveguide observed length and within a 7 nm repetitive spectral bandwidth due to a 60 μm sampling period. It employs nanoscale antennas to sample stationary waves within a surface-integrated waveguide, generating an under-sampled Fourier interferogram. Thanks to multi-nanowire antenna design, the system eliminates the need for bulky optical setups and it becomes compact and stable. Additionally, an optimized data reduction method is proposed to improve the spectral resolution and reduce the aliasing effect. With what we believe to be a novel approach, in a wavelength-meter configuration, a spectral resolution of 50 pm is demonstrated over a 14 nm spectral range. This initial demonstration paves the way for more complex and efficient integrated spectrometers in the future with the SWIFTS technology.