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

Modulation bandwidths of 24 GHz (I/sub bias/=25 mA) and 33 GHz (I/sub bias/=65 mA) are demonstrated for 3×100 μm
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In/sub 0.35/Ga/sub 0.65/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 facets using chemically-assisted ion-beam etching. Both the undoped and p-doped lasers also demonstrate modulation current efficiency factors exceeding 5 GHz/mA
¹
2/, the best reported results for any semiconductor laser.