Reconfigurable Optical Antenna Array with Sb2S3 Phase-Change Waveguides for Non-Mechanical Beam Steering at 1550 nm

Abstract

This paper presents the design and numerical analysis of a reconfigurable optical phased array (OPA) based on silicon nitride (Si3N4) waveguides integrated with antimony trisulfide (Sb2S3) phase-change material segments for non-mechanical beam steering at 1550 nm. By embedding 400 nm-wide Sb2S3 segments into Si3N4 ridge waveguides, a significant effective refractive index contrast of Δneff = 0.560 is achieved between the crystalline and amorphous states, enabling a phase shift of approximately 1.73 rad over a compact 1 μm segment length. Full-wave electromagnetic simulations demonstrate that a two-element array achieves a symmetric beam steering range of ±12° with a peak directivity of 12.3 dB and consistent side-lobe suppression. Furthermore, eight distinct three-element sub-array configurations are analyzed, providing discrete steering angles of 7 and 9 with main-lobe directivities up to 14.2 dBi. The proposed architecture offers a compact, non-volatile, and low-power solution suitable for solid-state light detection and ranging )LiDAR(, free-space optical communications, and adaptive beam control applications.