Photonic IC Spectrometer for Spacecraft

CubeSat/SmallSat bus infrastructure imposes stringent mass, power, footprint, and volume constraints on science instruments such as spectrometers. Nanohmics, Inc., proposes teaming with researchers at the Catholic University of America (CUA) to develop a real-time spectrometer that demonstrates photonic integrated circuit (IC) interferometric capabilities for the first time in the MWIR spectral band, and achieves extremely low size, weight and power (SWaP). The Nanohmics/CUA team proposes in Phase I to design and fabricate a proof of concept (PoC) photonic IC spectrometer operating in the MWIR, with TRL 3. Laboratory testing of the Phase I photonic IC device will strengthen the scaled-up photonic IC spectrometer prototype design for Phase II. The CUA research partner will perform finite-difference time-domain (FDTD) modeling and simulation. In Phase II, the team will fabricate and test the scaled-up photonic IC spectrometer prototype, achieving TRL 6. The photonic IC spectrometer uses an array of interferometers that are microfabricated on the IC to output a real-time spatial interference pattern that is similar to the spectrograph obtained via time-scanning in Fourier transform spectroscopy (FTS) such as Fourier transform spectroscopy (FTIR). However, the photonic IC spectrograph is instantaneous and obtained by an instrument with no moving parts, similar to a class of devices called a spatial heterodyne spectrometer (SHS). A stack of photonic IC spectrometers acts as a one-dimensional (1D) imaging array and performs hyperspectral imaging for remote sensing and other applications. Wavelengths in the MWIR range (~3-5 micrometers) will allow the use of common microfabrication techniques and materials, which will keep costs low. Our expertise in developing planar waveguide structures places Nanohmics in a unique position for fabricating photonic IC spectrometers.