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Design of double-layer silicon nitride-based optical phased array

We present a high-performance optical phased array on a double-layer Si3N4 platform, which takes the advantages of low macroscopic stress and low loss. We have performed both analytical and numerical simulations. In our design, the full width at half-maximum (FWHM) of the main lobe in transversal direction is 0.08°, while the FWHM in longitudinal direction is 0.09° due to the shallow etched grating antennas. The upward power is more than 50% in a broad wavelength range by optimizing the cladding thickness. The grating lobe suppression is reduced to 8.8 dB by using wide waveguide grating antennas. This optical phased array with high resolution and high efficiency will have a wide application in the fields of LIDAR and unmanned vehicles.