Experimental investigation on a Q-switched, mode-locked fiber laser based on the combination of active mode locking and passive Q switching

Abstract

We performed an experimental investigation on a Q-switched, mode-locked laser based on the combination of passive Q switching and active mode locking. This study was carried out using an erbium fiber ring laser incorporating an active mode locker employing a fast Si-based variable optical attenuator and a passive Q switch based on a carbon nanotube saturable absorber. It was found that stable Q-switched, mode-locked pulses can be readily generated when using a particular cavity modulation index and pump power. It was also found that our scheme can easily alter the operating regime among the Q switching, Q-switched mode locking, and mode locking by simply controlling the cavity modulation index and/or the pump power. For this particular laser configuration, the cavity modulation index and pump power operating conditions have been experimentally analyzed for three laser operating regimes. (C) 2012 Optical Society of America