Wide-angle non-uniform optical phased array using compact and efficient antenna design

Abstract

In the need for a more compact and efficient optical phased array with a wide steering beam for LIDAR applications, a wide steering array with high resolution is desirable. However, in the published work, a trade-off is often made for one over another. Apodized grating antennas have shown good efficiency with a compact size and wide beam profile, which improve optical phased array beam steering capability and are also compatible with the CMOS silicon photonics process. A promising studies shows enhancement in steering range with good resolution utilizing a non-uniform optical phased array. In this work, we present two highly efficient optical antennas with 94% and 93.5% upward power at the center frequency for the first and second antenna respectively, exceeding state-of-the-artwork to the best of our knowledge, and wide full-width half maximum of 8.88° x 78.05° and 7.53° x 69.85° in elevation and azimuthal planes, respectively. Both antennas provide a broad bandwidth across the 1400-1700 nm wavelength range with more than 80% efficiency in the S, C, and L bands. To overcome the limited scan ranges and small aperture size, a two-dimensional non-uniform array of 10 × 10 elements is utilized to increase the beam steering capability. A genetic algorithm is used to optimize the position of array elements, resulting in an aliasing-free array with a wide steering range of 160° with beam width 0.5° and consistent -11 dB maximum side lobe level across the steering range.