A 4096-element 3D-integrated Si-SiN optical phased array for high-power coherent LiDAR

Integrated optical phased arrays (OPAs) are pivotal for next-generation solid-state light detection and ranging (LiDAR), offering high-speed, inertia-free beam steering in a compact form factor. However, achieving high angular resolution alongside multi-watt emission power remains a formidable challenge. In this work, we present a 3D-integrated silicon-silicon nitride (Si-SiN) hybrid OPA comprising 4096 (4 × 1024) elements, packaged with a CMOS driver chip via flip-chip bonding. The proposed heterogeneous Si-SiN architecture leverages PN carrier-depletion phase shifting with sub-nanosecond response capability, currently demonstrating a 2 μs CMOS-driven beam switching time and ultra-low-power (1.5 μW/π), while delivering an angular resolution of 0.038° × 0.017° (FWHM) and a total main-lobe CW emission power of 1.5 W at a 20 W high-power injection. This approach effectively circumvents silicon's nonlinear limitations while maintaining high-density integration. System-level validations include indoor coherent detection and a four-channel phase-locked synthetic aperture scheme that successfully compresses the beam divergence to 300 μrad. This architecture provides a scalable roadmap for the development of high-performance, long-range solid-state LiDAR systems.