Optimized amplitude distributions for grating and side lobe suppression in optical phased array antennas

Integrated optical phased arrays (OPAs) are important for various applications such as LIDAR, microscopy, wireless communication, and holography. Traditional one-dimensional N-element OPAs with individual phase shifters for varied steering angles often have emitter spacings that exceed half a wavelength, leading to grating lobes. Moreover, using true-time-delay lines with varied numbers of periods for different delays may cause amplitude inconsistencies and further side lobe elevation. The proposed partially apodised (PA) one-dimensional grating waveguide design controls amplitude while conserving the time delay for targeted steering angles, using distributions as Uniform to minimize grating and side lobes. We fabricated a four-element array with insertion losses of -3 dB for the PA version across the 1530-1580 nm wavelength band.