Inverse-Designed Non-Uniform Silicon Nitride Gratings With High Beam Steering Performance

Non-uniform silicon nitride grating antennas are designed by inverse-design method. In the wavelength range of 1500-1590 nm, the non-uniform gratings exhibit a large scanning range of 13.2° and high wavelength tuning efficiency of 0.147 °/nm, nearly 2.4 times that of the uniform gratings, along with superior transmission and directionality performance. At 1550 nm, a high side mode suppression ratio of 4.32 dB is obtained for the non-uniform gratings, much higher than that of the uniform gratings (1.00 dB). This work may pave the way for the development of silicon nitride-based miniaturized optical phased arrays with excellent beam steering performance.