High-power low-divergence semiconductor lasers for GaAs-based 980-nm and InP-based 1550-nm applications

High-power diode lasers with low-vertical divergence and high-fiber coupling efficiency were developed for GaAs-based 980-nm pump lasers and InP-based 1550-nm Fabry-Perot and distributed-feedback (DFB) lasers, Narrow divergence at 980 nm was made possible by a large optical-mode waveguide design, with full-width at half-maximum (FWHM) far-field angles of 11.7 degrees x 17.8 degrees and coupling efficiency of 80% into a cleaved single-mode fiber (SMF), A vertical taper processing technique was developed for InP-based laser structures, Fabry-Perot lasers produced over 90-mW output power, 17 degrees x 16 degrees FWHM beam divergence angles, and 63% coupling efficiency into a lensed SMF, The vertical taper was successfully integrated in 1550-nm DFB lasers, and over 80-mW single-mode output power with beam divergence angles of 12 degrees x 14 degrees was obtained.