High-resolution aliasing-free optical beam steering

TLDR

Many applications such as LIDAR, free‑space optical communications, and spatially resolved optical sensors require compact, robust beam‑steering solutions, yet achieving high steering resolution with wide angle and low divergence is limited by trade‑offs, and chip‑based two‑axis optical phased arrays have so far achieved no more than 23 resolvable spots. The authors aim to demonstrate a two‑axis steerable optical phased array with dramatically higher performance, targeting over 500 resolvable spots and 80° steering while maintaining record low divergence. They achieve this by employing non‑uniform emitter spacing on a large‑scale emitter array fabricated in a 300 mm CMOS facility. The resulting device delivers over 500 resolvable spots, 80° steering in the phased‑array axis, a record 0.14° divergence in both axes, and enables two‑dimensional beam steering to more than 60,000 resolvable points.

Abstract

Many applications, including laser (LIDAR) mapping, free-space optical communications, and spatially resolved optical sensors, demand compact, robust solutions to steering an optical beam. Fine target addressability (high steering resolution) in these systems requires simultaneously achieving a wide steering angle and a small beam divergence, but this is difficult due to the fundamental trade-offs between resolution and steering range. So far, to our knowledge, chip-based two-axis optical phased arrays have achieved a resolution of no more than 23 resolvable spots in the phased-array axis. Here we report, using non-uniform emitter spacing on a large-scale emitter array, a dramatically higher-performance two-axis steerable optical phased array fabricated in a 300 mm CMOS facility with over 500 resolvable spots and 80° steering in the phased-array axis (measurement limited) and a record small divergence in both axes (0.14°). Including the demonstrated steering range in the other (wavelength-controlled) axis, this amounts to two-dimensional beam steering to more than 60,000 resolvable points.