Self-calibration adaptive lidar aperture building-block light engine

Abstract

A serpentine delay-line waveguide feeding an array of grating couplers can be fabricated in a silicon photonic chip, or tile, with the grating couplers emitting light at an angle that varies with wavelength and delay between the couplers imparted by the waveguide. The beam-steering tile can be used to transmit or receive light from a scene. The tile can be arrayed with one or more other tiles for bistatic radar-lidar operation. A tile in the array may transmit probe and frequency-shifted reference beams, while another tile may receive a return at a heterodyne frequency giving a range to the scene. The pitch of the serpentine delay line may be different for transmitting and receiving tiles to suppress returns from unwanted directions. Pairs of phase-cohered tiles may illuminate a spot in the scene with fringe patterns, producing oscillating returns that can be processed to form a high-resolution sub-image by Fourier synthesis.