隧道结级联多有源区激光器光束整形与合束系统OA

In tunnel-junction-based semiconductor lasers with cascaded multi-active-region structures,the emission regions are typically optically isolated in the lateral direction,leading to multiple incoherent and spatially separated far-field patterns.After fast-axis collimation,the output beam exhibits a series of angularly symmetric but discrete pat-terns,which significantly increase the far-field divergence and maintain a multi-spot intensity profile.When the beam is focused or imaged,this angular separation degrades the focal quality,thereby limiting the fiber-coupling efficiency and output brightness.To address this issue,a beam-shaping method based on critical-angle-controlled total internal reflec-tion(TIR)prisms is proposed.The design employs a TIR prism array in combination with a symmetric high-reflectivity prism to reconstruct the angular distribution of emissions from multiple active regions via selective reflection near the critical angle.As a result,the initially discrete triple-peak distribution in angular space is transformed into a single con-centrated peak,reducing the fast-axis divergence from 0.52°to 0.11°,corresponding to an angular compression ratio of approximately 79％.This effectively enhances the directional uniformity of the multi-emitter output beam.By integrat-ing a fast-axis dark-zone compression prism with a Galilean beam-compression system,the beam parameter products(BPPs)of both the fast and slow axes are further balanced.After beam shaping,the fast-axis BPP decreases from 54.6 mm·mrad to 22.8 mm·mrad,while the focal-plane intensity evolves from a discrete triple-spot pattern to a single com-pact spot.The focused beam is efficiently coupled into a 300 μm-core fiber with a numerical aperture of 0.22,achiev-ing a peak output power of 630 W and an optical-to-optical conversion efficiency of 78.8％.Furthermore,analyses of as-sembly and fabrication tolerances,thermo-mechanical coupling,and spectral dispersion as well as thermo-optic effects confirm the stability and feasibility of the proposed TIR-based beam-shaping and combining scheme,demonstrating its strong potential for high-brightness multi-emitter semiconductor laser systems.