Dynamic modeling of Optical Phased Arrays

Optical Phased Arrays (OPAs) based on liquid crystals (LCs) have useful properties for all-electronic beam steering. Typical devices contain hundreds to thousands of individually-controlled phase shifters. Their behavioral dynamics are modeled in this paper starting from the physics of the LC in a single phase shifter. Results relevant to two useful device types are presented. The first is an endless phase shifter, suitable for adjusting and maintaining coherence throughout a multiple-subaperture optical beamforming (Tx or Rx) system. The second is a beam steerer, also applicable to such systems. Throughput, phase lag, and beam-shape modifications are found and compared with experiment. A simple heuristic form describing the performance, suitable for systems-engineering use, is also presented.