Experimental investigations on the suppression of Q switching in monolithic 40 GHz mode-locked semiconductor lasers

Inherent Q switching as a source of intracavity pulse energy modulations, i.e., unwanted amplitude noise, is still a challenging task in order to fabricate monolithic mode-locked semiconductor lasers in view of different commercial applications. In this letter, the results of experimental investigations on the influence of the quantum well number on the occurrence and suppression of Q switching in 40 GHz mode- locked multiple quantum well lasers are presented. Improved mode-locked lasers emit short optical pulses (<=1.6 ps) with very low amplitude noise (1%-2%) and timing jitter (50-100 fs).