Integrated Optical Phased Array with 180-Degree Field of View for Solid-State 2D Optical Beam Steering

We present our recent progress in integrated silicon optical phased array (OPA), which overcomes long-standing challenges in achieving high-performance solid-state 2D optical beam steering. Our OPA chip demonstrates aliasing-free beam steering across a full 180° field of view, combined with high beam quality, including side-lobe levels below -19 dB and main-lobe efficiency exceeding 92%. These results are achieved by using a half-wavelength-pitch waveguide array, a trapezoidal slab grating as a single emitter, and Gaussian amplitude distribution among all the channels. Conventional OPAs employ an array of waveguide gratings as emitters. To achieve a full 180^{\circ } field of view (FOV), the spacing between these grating emitters needs to be reduced to half a wavelength or less. However, such close spacing often results in significant crosstalk, degrading beam quality. In contrast, the slab grating design transforms the coupling between adjacent channels into a beneficial one. The consistent coupling in the slab region enables controlled near-field interference and beamforming, and then the light beam is emitted to the far field without grating lobes. This advancement has significant potential for a broad range of applications such as light detection and ranging (LiDAR), free-space optical communications, 3D holography and biomedical imaging.