A Wavelength-Scalable Dual-Stage Photonic Integrated Circuit Spectrometer

In this program, Physical Sciences Inc. (PSI) will team with Professor Ali Adibi’s group at the Georgia Institute of Technology to develop a photonic integrated circuit (PIC) spectrometer that can simultaneously achieve high-resolution over wide-bandwidths using a scalable and foundry-ready approach. While a PIC-based spectrometer is a key component for on-chip Raman, fluorescence, and absorption spectroscopy, it is also a general purpose tool for PIC designers when available within a foundry’s process-design kit (PDK). Our approach cascades two complimentary devices: a first-stage  wide-bandwidth (>200 nm) coarse spectrometer formed using an echelle or arrayed-waveguide grating feeding a series of second-stage high-resolution (<1 nm) spectrometers consisting of arrays of high-quality-factor micro-resonators. Using a passive photonics platform with low-loss SiN waveguides and high-performance off-chip detectors enables high quantum efficiencies (>10%) that are fully compatible with low temperature operation (–40°C). Our approach is also highly adaptable and scalable in terms of center wavelength; it can be designed to operate over >200-nm bands throughout the visible and near-infrared wavelength regimes.  In Phase II of this effort, we will adapt this spectrometer to a commercial foundry, including developing a PDK, and demonstrate waveguide-enhanced Raman (WER) spectroscopy.