730-nm-emitting Al-free active-region diode lasers with compressively strained InGaAsP quantum wells

Abstract

0.73-μm-emitting, Al-free active-region, strained (Δa/a≈1.4%) InGaAsP single-quantum-well diode lasers have been grown by low-pressure metal–organic chemical-vapor deposition. A broad waveguide laser design with In0.5(Ga0.5Al0.5)0.5P cladding layers is utilized to achieve a large effective transverse spot size (d/Γ=0.433 μm) and to minimize carrier leakage from the active region. Threshold current densities of 514 A/cm2 (100-μm-wide stripe, L=1 mm), external differential quantum efficiencies of 60%, and characteristic temperature coefficients for the threshold current, T0, and external differential quantum efficiency characteristic temperature, T1, have values of 72 and 153 K, respectively. Continuous wave output powers of 1.4 W are obtained from facet-coated (90%/10%) devices operating at 735 nm.