Low-bias-current direct modulation up to 33 GHz in InGaAs/GaAs/AlGaAs pseudomorphic MQWRidge-waveguide lasers

Modulation bandwidths of 24 GHz (Ibias=25 mA) and 33 GHz (Ibias=65 mA) are demonstrated for 3*100 mym2 In0.35 Ga0.65 As/GaAs multiple quantum well ridge-waveguide lasers with undoped and p-doped active regions, respectively. These performance enhancements have been achieved both by lowering the growth temperature of the high-Al-mole-fraction cladding layers and by utilizing short-cavity devices, fabricated with dry-etched facts using chemically-assisted ion-beam etching. Both the undoped and p-doped lasers also demonstrate modulation current efficiency factors exeeding 5 GHz/mA 1/2, the best reported results for any semiconductor laser.