High-power (>10 W) continuous-wave operation from 100-μm-aperture 0.97-μm-emitting Al-free diode lasers

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Abstract
By incorporating a broad transverse waveguide (1.3 μm) in 0.97-μm-emitting InGaAs(P)/InGaP/GaAs separate-confinement-heterostructure quantum-well diode-laser structures we obtain record-high continuous-wave (cw) output powers for any type of InGaAs-active diode lasers: 10.6–11.0 W from 100-μm-wide-aperture devices at 10 °C heatsink temperature, mounted on either diamond or Cu heatsinks. Built-in discrimination against the second-order transverse mode allows pure fundamental-transverse-mode operation (θ⊥=36°) to at least 20-W-peak pulsed power, at 68×threshold. The internal optical power density at catastrophic optical mirror damage (COMD) P̄COMD is found to be 18–18.5 MW/cm2 for these conventionally facet-passivated diodes. The lasers are 2-mm-long with 5%/95% reflectivity for front/back facet coating. A low internal loss coefficient (αi=1 cm−1) allows for high external differential quantum efficiency ηd (85%). The characteristic temperatures for the threshold current T0 and the differential quantum efficiency T1 are 210 and 1800 K, respectively. Low differential series resistance Rs: 26 mΩ; leads to electrical-to-optical power conversion efficiency values in excess of 40% from 1 W up to 10.6 W cw output power, and as much as 50% higher than those of 0.97-μm-emitting Al-containing devices.