Large-scale silicon nitride nanophotonic phased arrays at infrared and visible wavelengths

TLDR

We demonstrate passive large‑scale nanophotonic phased arrays in a CMOS‑compatible silicon photonic platform. Silicon nitride waveguides enable higher input power and lower phase variation compared to silicon‑based networks. We achieved a record 1550‑nm phased array with a 4 mm × 4 mm aperture, 0.021° × 0.021° diffraction‑limited spot, 10 dB side‑lobe suppression and 400 mW main‑beam power, and demonstrated the first large‑aperture 635‑nm visible array (0.5 mm × 0.5 mm) with a 0.064° × 0.074° spot.

Abstract

We demonstrate passive large-scale nanophotonic phased arrays in a CMOS-compatible silicon photonic platform. Silicon nitride waveguides are used to allow for higher input power and lower phase variation compared to a silicon-based distribution network. A phased array at an infrared wavelength of 1550 nm is demonstrated with an ultra-large aperture size of 4 mm×4 mm, achieving a record small and near diffraction-limited spot size of 0.021°×0.021° with a side lobe suppression of 10 dB. A main beam power of 400 mW is observed. Using the same silicon nitride platform and phased array architecture, we also demonstrate, to the best of our knowledge, the first large-aperture visible nanophotonic phased array at 635 nm with an aperture size of 0.5 mm×0.5 mm and a spot size of 0.064°×0.074°.