LOCKING BANDWIDTH OF ACTIVELY MODE-LOCKED SEMICONDUCTOR-LASERS

The locking bandwidth of an actively mode-locked semiconductor laser i s a measure of its tolerance to variations in the input drive frequenc y. At frequencies outside the locking bandwidth, the output pulses fro m the laser exhibit large amplitude fluctuations and timing jitter. Th is paper investigates the locking bandwidths of fundamentally driven a nd harmonically driven high-repetition-rate actively mode-locked semic onductor lasers. We show that the locking bandwidth is maximized when the cavity length is minimized. The locking bandwidth is related to an important constant, the ''pull-in time''. Experimental data and numer ical modeling show that the pull-in time is a function of the optical bandwidth of the system and the RF drive level.