Low-loss, low-threshold 0.98 μm wavelength InGaAsP/InGaP/GaAs broadened waveguide lasers grown by GSMBE

We describe the design and experimental results for broadened waveguide (BW) high-power, low-loss, low threshold current 0.98 μm-aluminum-free InGaAsP/InGaP/GaAs lasers. The dramatic decrease in the internal losses with an increase in the width of the waveguide layer for a SCH-MQW structure, is attributed to lower free-carrier absorption due to the reduced overlap of the optical mode with the highly doped cladding regions. The BW lasers grown with both InGaAsP and GaAs waveguides show lower internal loss and threshold current than those designed for optimum optical confinement factor within the QW region. We report a record low internal loss of 2.2 cm^-1 and highest CW output power of 6.8 W for a InGaP/GaAs laser grown by GSMBE. We also report the highest quasi-continuous output power of 13.3 W measured for a single 100 μm aperture, 0.8-0.98 μm Al-free laser diode, grown by either MBE or MOCVD