CW PERFORMANCE OF AN INGAAS-GAAS-ALGAAS LATERALLY-COUPLED DISTRIBUTED-FEEDBACK (LC-DFB) RIDGE LASER-DIODE

Single-mode distributed feedback (DFB) laser diodes typically require a two-step epitaxial growth or use of a corrugated substrate. We demonstrate InGaAs-GaAs-AlGaAs DFB lasers fabricated from a single epitaxial growth using lateral evanescent coupling of the optical field to a surface grating etched along the sides of the ridge, A CW threshold current of 25 mA and external quantum: efficiency of 0.48 mW/mA per facet were measured for a 1 mm cavity length device with anti-reflection coated facets. Single-mode output powers as high as 11 mW per facet at 935 nm wavelength were attained, A coupling coefficient of at least 5.8 cm(-1) was calculated from the subthreshold spectrum taking into account the 2% residual facet reflectivity.