HIGH-POWER HIGH-EFFICIENCY 0.98-MU-M WAVELENGTH INGAAS-(IN)GAAS(P)-INGAP BROADENED WAVE-GUIDE LASERS GROWN BY GAS-SOURCE MOLECULAR-BEAM EPITAXY

We describe the design and experimental results for high-power, high-e fficiency, low threshold current, 0.98 mu m wavelength, broadened wave guide (BW) aluminum-free InGaAs-(In)GaAs(P)-InGaP lasers, The decrease in the internal losses with an increase in the width of the waveguide layer for a separate-confinement heterostructure multiple-quantum-wel l (SCH-MQW) structure is attributed to lower free-carrier absorption d ue to the reduced overlap of the optical mode with the highly doped cl adding regions, The BW lasers grown with both InGaAsP and GaAs wavegui des show lower internal losses and similar threshold currents than tho se designed for an optimum optical confinement factor within the QW re gion, We report a record-low internal loss of 1.8 +/- 0.2 cm(-1) for ( In)GaAs(P)-InGaP lasers grown by gas-source molecular beam epitaxy (GS MBE). The temperature dependence of internal loss suggests that optica l loss from free-carrier absorption in the waveguide dominates at T > 40 degrees C, while near room temperature, the residual loss is attrib uted to scattering and free-carrier absorption in the QW's, The relati ve insensitivity of internal loss near room temperature has enabled th e use of a simplified InGaAs-GaAs-InGaP BW structure to achieve very h igh CW and quasi-CW (QCW) power operation, We report the highest CW ou tput power of 6.8 W for a GaAs-InGaP laser, and the highest quasi-cont inuous output power of 13.3 W measured for a single 100-mu m-wide aper ture, 0.8-0.98-mu m wavelength Al-free laser diode grown by GSMBE.