Large‐Signal Effects in Self‐Locked Lasers

摘要

Most past studies of mode locking are concerned with conditions near laser threshold. In this paper we use numerical analysis to study large‐signal conditions. Specifically, we restrict ourselves to a traveling wave cavity, a homogeneously broadened line, and a small spatial extent of the medium. The density matrix equations characterizing the medium and Maxwell's equations are solved by computer. It is found for small pump power that mode locking and spike formation occur as previously predicted by the small‐signal theory. As the pump intensity is increased, the spike amplitude increases to a certain critical level and then upon further increasing the pump power, the spike repetition frequency increases discontinuously to twice, three times, four times, etc., its original value. The critical spike amplitudes are not simply related to 180° pulses.