High-Power-Compatible Thick Silicon-on-Insulator Waveguide: An Implementation in Optical Phased Array

High-power transmission capability is a critical yet insufficiently explored frontier in integrated photonics. Owing to the restricted optical cross-sectional area of the 220 nm-thick silicon layer, conventional SOI platform is incapable of managing the nonlinear optical losses and thermal loads induced by high-power continuous-wave (CW) light. For high-power applications, we propose a strategy that combines a 500 nm-thick silicon layer with 800 nm-wide waveguide beyond single mode regime. Experimental results confirm that the proposed waveguide sustains stable transmission at 1550 nm under a high input power, and, compared with the single-mode waveguide, exhibits a higher on-chip power threshold and a relatively lower nonlinear loss. Based on this platform, we demonstrate a 64-element two-dimensional optical phased array (OPA) with a uniform circular aperture design with footprint of 3 mm × 2.5 mm and fabricated using a standard silicon photonics process. By incorporating efficient calibration algorithm, we achieve a sidelobe suppression ratio (SLSR) exceeding 4.45 dB at the central direction and enable two-dimensional beam steering over a 10° × 8° field with SLSR greater than 3.1 dB.