Multibeam Shaping of Laser Diode Arrays via Phase-Functional Decomposition for Monolithic Integration

Laser diode arrays (LDAs) offer scalable optical power for projection, materials processing, and sensing. Yet their inherent multibeam architecture, featuring spatially separated emitters, noncollinear propagation, and disparate divergence angles, impedes compact, alignment-free beam shaping. Conventional approaches rely on cascaded, bulky, and alignment-sensitive optics, limiting system integration, stability, and efficiency. Here, we introduce a unified phase-engineering framework for the design of a monolithic diffractive optical element (DOE), capable of integrating multiple beam-shaping functions into a single phase profile. Exploiting functional decomposition of the target wavefront, we encode three independent beam-shaping functions via linear phase superposition: (i) per-beam collimation and propagation-direction correction; (ii) pixel-level intensity redistribution to synthesize arbitrary far-field patterns; and (iii) spatial combining onto a shared focal plane. Critically, this framework enables full multibeam control without moving parts or alignment-sensitive assemblies. Simulations confirm the effectiveness and design flexibility of the proposed phase-engineering framework for flat-top circular, rectangular, and triangular profiles. Experimentally demonstrated on a 7-element LDA, the proposed strategy achieves high-contrast flat-top patterns with >80% diffraction efficiency and >86% intensity uniformity. This work establishes a generalizable, fabrication-ready framework for integrated multibeam photonics, resolving the fundamental scalability–compactness trade-off in next-generation laser systems.