A 970 nm strained-layer InGaAs/GaAlAs quantum well laser for pumping an erbium-doped optical fiber amplifier

We report the performance of a 970 nm strained-layer InGaAs/GaAlAs quantum well laser and its application for pumping Er-doped optical fiber amplifiers. The laser was grown by molecular beam epitaxy and has three In0.2Ga0.8As/GaAs quantum wells. For a 5-μm-wide and 400-μm-long ridge-waveguide laser, a cw threshold current of 20 mA and an external quantum efficiency of 0.28 mW/mA per facet were obtained. Maximum output power exceeds 32 mW/facet. With antireflection coating, even higher external quantum efficiency (0.40 mW/mA) was achieved, and more than 20 mW of power was coupled into a single mode fiber. Preliminary experiments of pumping the Er-doped fiber amplifier gave 15 dB of gain at 1.555 μm for a pump power of 14 mW into the Er fiber.