Interdigital waveguide grating antenna array for an optical phased array

To address the issues of beam divergence, emission loss, and field of view (FOV) limitation for an optical phased array (OPA), we propose a novel, to our knowledge, interdigital waveguide grating antenna (WGA) array. This array comprises four WGAs with varying etching periods, where antennas with identical periods are interleaved to achieve bidirectional scanning fields. By selecting antennas with different periods, the entire array enables longitudinal wide-field stitching scanning. Furthermore, to enhance directivity, the WGAs in the array utilize a Si 3 N 4 -Si dual-layer structure, breaking the vertical symmetry of traditional antennas to reduce light leakage to the substrate. As a result, a high directivity of 97.4% is achieved, with a waveguide emission length at 21.37 mm, and a far-field longitudinal divergence angle of 0.0037°. Ultimately, we simulate the pointing performance of the entire interdigital array. The results demonstrate a longitudinal scanning range of up to 103.44° with a tuning precision of 1.03°/nm.