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

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 x 4 mm, achieving a record small and near diffraction-limited spot size of 0.021 degrees x 0.021 degrees with a side lobe suppression of 10 dB. A main beam power of 400mW 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 x 0.5 mm and a spot size of 0.064 degrees x 0.074 degrees. (C) 2016 Optical Society of America