THE CRUCIAL ROLE OF DOPING FOR HIGH-REPETITION-RATE MONOLITHIC MODE-LOCKING OF MULTIPLE-QUANTUM-WELL GAAS ALGAAS LASERS/

Monolithic colliding pulse mode locking of a molecular beam epitaxy (M BE) grown GaAs/AlGaAs quantum well laser has been achieved through bac k doping of the active region to simulate the residual doping present in metal organic vapor phase epitaxy grown mode-locked laser wafers. F requency domain measurements are presented which show multiple collidi ng pulse mode-locked operation of an MBE grown device at 186 and 372 G Hz. Devices with no intentional doping in the active laver showed no e vidence of mode-locked operation, Band-edge absorption spectra are als o presented which indicate the effect doping has in broadening the exc itonic linewidth in the saturable absorber. (C) 1997 American Institut e of Physics.