Strained‐layer In0.35Ga0.65As‐GaAs‐AlGaAs graded index separate confinement heterostructure multiple quantum well lasers were grown by molecular beam epitaxy and processed as ridge waveguide structures. Devices with 3 &mgr;m×200 &mgr;m 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 &mgr;m×200 &mgr;m 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.