REFLECTION-INDUCED CHANGES IN THE OPTICAL-SPECTRA OF 980-NM QW LASERS

High-power 980-nm strained quantum well diode lasers having low reflectivity facet coatings are sensitive to weak reflections that affect the laser emission spectrum. In devices having 0.2% output facet reflectivity, 2% reflections from an external plane mirror shifted the output spectrum from 970 to 1000 nm. Wavelength stabilization and improved immunity to spurious reflections were demonstrated using bulk grating and fiber-grating reflectors. Continuous laser tuning from 958 to 1011 nm was achieved with 1% net grating reflectivity.