A diode-pumped Nd:KGd(WO4)2 laser mode locked by a saturable Bragg reflector (SBR) is passively stabilized to suppress Q -switched mode locking and to extend the parameter range of continuous-wave mode locking. An indium phosphide plate exhibiting two-photon absorption and free-carrier absorption is used for passive stabilization. The intracavity pulse energy for the onset of stable continuous-wave mode locking is reduced by a factor of 4 compared with the laser without stabilization. By increasing the modulation depth of the SBR, pulse shortening by 30% is achieved and bandwidth-limited 6.2-ps pulses are measured.
© 2004 Optical Society of America
Pavel Černý, Gareth Valentine, David Burns, and Kenneth McEwan, "Passive stabilization of a passively mode-locked laser by nonlinear absorption in indium phosphide," Opt. Lett. 29, 1387-1389 (2004)