Generation of ultrashort pulses in a negative-feedback laser

The results are given of theoretical and experimental investigations of stimulated emission from a modelocked negative-feedback solid-state (ruby) laser. Under certain conditions, governed by the delay time in the feedback circuit, the laser suffers from high-frequency instabilities in the form of sehvlocked intermode beats. These instabilities increase significantly the stringency of the requirements which have to be satisfied if negative feedback is to be used for amplitude stabilization.