Efficient light transmission, reception and beam forming in photonic crystal beam steering device in a phased array configuration

Abstract

We have studied non-mechanical beam steering and light detection and ranging (LiDAR) based on photonic crystal waveguides (PCWs). We suppose a situation that a light beam transmitted from a PCW hits a distant object and a part of returned light is received by the same PCW. In this process, one may expect a large reception intensity by a long PCW, but it is actually constrained by the propagation loss of the PCW. To reduce this loss, we propose, in this paper, a serial array configuration of PCWs, in which returned light is received by multiple short PCWs and then summed in a waveguide circuit. We theoretically estimate its reasonable transmission efficiency and high reception power, which allows the scaling of the device. We also show that a sharp beam is repeatedly formed without phase control by scanning the wavelength, which becomes each resolution point of image acquisition in LiDAR.