1000-Channel Integrated Optical Phased Array with 180{\deg} Field of View, High Resolution and High Scalability

TL;DR

This paper presents a scalable 1000-channel optical phased array achieving a 180-degree field of view, high resolution, and low side-lobe levels, advancing compact beam steering technology for applications like LiDAR and optical communication.

Contribution

The work introduces a large-scale 1000-channel OPA with optimized waveguide routing and a passive PWM control scheme, enabling wide-angle, high-resolution beam steering with simplified control complexity.

Findings

Achieved grating-lobe-free beam steering over 180° FOV

Attained high resolution of 0.07° x 0.17°

Minimum side-lobe level of -18.7 dB

Abstract

Optical phased array (OPA) is a promising technology for compact, solid-state beam steering, with applications ranging from free-space optical communication to LiDAR. However, simultaneously achieving a large field of view (FOV), high resolution, and low side-lobe level (SLL) remains a major challenge. Traditional OPAs face inherent limitations: they exhibit grating lobes when emitter spacing exceeds half the operating wavelength, while at half-wavelength spacing, significant crosstalk issues persist. Previously, we demonstrated a small-scale OPA that harnesses near-field interference and beamforming via a trapezoidal slab grating and a half-wavelength-pitch waveguide array to achieve a 180{\deg} FOV. However, its resolution was limited by the small channel count. In this work, we present a 1000-channel OPA that scales this architecture while addressing key challenges in waveguide crosstalk and control complexity. By optimizing waveguide routing, we minimize inter-channel coupling in the dense waveguide array. Additionally, we propose and demonstrate a passive matrix control scheme using 20 row and 50 column pulse-width modulation (PWM) signals to arbitrarily control 1000 thermo-optic phase shifters, significantly simplifying the electronic control and packaging. Our OPA achieves grating-lobe-free beam steering across a full 180{\deg} FOV, with a high resolution of 0.07{\deg} * 0.17{\deg} and a minimum SLL of -18.7 dB at 0{\deg}. This large-scale, cost-effective chip-based OPA paves the way for next-generation high-resolution, wide-angle beam steering systems.