2D broadband beamsteering with large-scale MEMS optical phased array

Optical-phased arrays (OPAs) enable complex beamforming, random-access beam pointing, and simultaneous scan and tracking of multiple targets by controlling the phases of two-dimensional (2D) coherent emitters. So far, no OPA can achieve all desirable features including large 2D arrays, high optical efficiency, wideband operation in wavelengths, fast response time, and large steering angles at the same time. Here, we report on a large-scale 2D OPA with novel microelectro- mechanical-system (MEMS)-actuated phase shifters. Wavelength-independent phase shifts are realized by physically moving a grating element in the lateral direction. The OPA has 160 × 160 independent phase shifters across an aperture of 3.1 mm× 3.2 mm. It has ameasured beam divergence of 0.042° × 0.031°, a field of view(FOV) of 6.6° × 4.4°, and a response time of 5.7 µs. It is capable of providing about 25,600 rapidly steerable spots within its FOV. The grating phase shifters are optimized for the near-infrared telecom wavelength bands from 1200 to 1700 nm with 85% optical efficiency.