Carrier lifetime and modulation bandwidth of a quantum well AlGaAs/InGaP/GaAs/InGaAs transistor laser

A quantum well (160 A) transistor laser with a 400 mu m cavity length that achieves the large 3 dB modulation bandwidth of 13.5 GHz is described. The fast base recombination (transport determined, tau(BL)< 10 ps) permits improvement of the carrier-photon damping ratio (> 1/root 2), resulting in a resonant peak magnitude of unity and consequently a resonance frequency of similar to 0 GHz (no peak) in the small-signal response. Quantum well band filling and bandwidth saturation are observed on the ground state (lambda=1000 nm), and increase with operation on the first excited state (lambda=980 nm). (c) 2006 American Institute of Physics.