High-speed modulation of strained-layer InGaAs-GaAs-AlGaAs ridge waveguide multiple quantum well lasers

Abstract
Strained‐layer In0.35Ga0.65As‐GaAs‐AlGaAs graded index separate confinement heterostructuremultiple quantum well lasers were grown by molecular beam epitaxy and processed as ridge waveguide structures. Devices with 3 μm×200 μm cavities have threshold currents of 18 mA (3000 A/cm2) and optical waveguide losses of 4.2 cm−1. The microwave modulation bandwidth of a 3 μm×200 μm device was determined to be 19.5 GHz, which exceeds the 15.5 GHz reported for multimode index‐guided devices, and is the highest direct modulation bandwidth reported for a quantum well laser.