Scalable low-power silicon photonic platform for all-solid-state beam steering

Solid-state beam steering is the key to realize miniature, mass-producible LIDAR (Light Detection And Ranging) and free-space communication systems without using any moving parts. The huge power consumption required in solid-state beam steering, however, prevents this technology from further scaling. Here we show two different approaches to enable low-power solid-state beam steering. In the first approach, we use spatial-mode multiplexing to reduce the power consumption of the phase shifters in a large-scale optical phased array. We show an improvement of phase shifter power consumption by nearly 9 times, without sacrificing optical bandwidth or operation speed. Using this approach, we demonstrate 2D beam steering with a silicon photonic phased array containing 512 actively controlled elements. This phased array consumes only 1.9 W of power while steering over a 70 degrees x 6 degrees field of view. This power consumption is at least an order of magnitude lower compared to other demonstrated large-scale active phased arrays. In the second approach, we achieve 2D beam steering with a switchable emitter array and a metalens that collimates the emitted light. The power consumption of this approach scales logarithmically with the number of emitters and therefore favors large-scale systems. This approach allows straightforward feedback control and better robustness to environmental temperature change. Our approaches demonstrate a path forward to build truly scalable beam steering devices.