Low threshold 1.3 µm GaInAsP/InP buried optical waveguide lasers

Low threshold GaInAsP/InP Buried Optical Waveguide lasers emitting at 1.3 µm were successfully fabricated by two step liquid phase epitaxy. Room temperature CW threshold current as low as 59 mA (corresponding to ∼ 11 mA per micron active stripe width) and CW differential quantum efficiencies of 26%/facet was achieved. CW operation was achieved for these devices at heat sink temperatures as high as 70°C. A single transverse mode (∼ 13 to 20° angular divergence) was obtained at more than twice the threshold current. The mechanism for transverse mode stabilization is believed to result from scattering "losses" suffered by the higher order transverse modes at the buried mesa sidewalls. No relaxation oscillation was observed in their transient response.