1.1W continuous-wave, narrow spectral width, (<1Å) emission from broad-stripe, distributed-feedback diode lasers (λ=0.893μm)

By etching a distributed-feedback grating directly into the Al-free optical confinement region of a 100 mu m stripe InGaAs/InGaP/GaAs diode laser, 1.1 W cw front-facet output power has been obtained at 0.893 mu m with a spectral full width at half maximum of 0.9 Angstrom. These devices have 1 mm long cavities and shallow gratings with a coupling coefficient, kappa similar to 7 cm(-1). The combination of long device length and low grating coupling results in both efficient operation as well as a longitudinally uniform field profile. As a result, all excited lateral modes oscillate at the same longitudinal cavity resonance to high power levels. Using shallow gratings etched in an InGaP upper confinement layer permits the growth of a high-quality cladding layer over the grating surface yielding excellent device performance. Facet-coated (5%/95%) devices demonstrate external differential quantum efficiencies of 51% and peak wallplug efficiencies of 32% at 1.1 W cw output power. (C) 1998 American Institute of Physics. [S0003-6951(98)00441-0].