Inverse-designed polarization multiplexing non-uniformly distributed gratings for one-dimensional beam steering

Non-uniformly distributed gratings on the silicon-on-insulator platform for one-dimensional beam steering are designed by direct binary search inverse-design method. The gratings exhibit good emission directionality and far-field characteristics. Within a relatively small wavelength tuning range of 1517-1577 nm, the longitudinal scanning angle for TE and TM light is 23.65 degrees and 10.81 degrees, respectively, both of which are much larger than their uniform counterparts. By polarization multiplexing and etching depth optimization, a remarkable longitudinal scanning angle of 32.10 degrees and high beam steering efficiency of 0.55 degrees/nm are obtained. This work may pave the way for the development of miniaturized optical phased arrays with excellent beam steering performance.