Problem of Spike Elimination in Lasers

We have investigated theoretically and experimentally the conditions under which spiking in the laser output can be completely suppressed. It is predicted that a nonlinear absorber in the cavity producing greater loss at the higher power levels, and vice versa, should be highly effective. Experimental work was carried out with a single-mode traveling-wave laser, since in this case the predictions can be most easily checked. Instead of using a nonlinear absorber, a Kerr cell controlled by a feedback circuit was used. It was found, in agreement with theory, that the time delay between the build-up of the electromagnetic energy in the cavity and the corrective action of the Kerr cell is a rather important parameter. Spike suppression can only be obtained when this time delay is short as compared to the duration of one oscillation pulse.