cw instability and steady-state pulses in a ring laser with intracavity parametric amplification
Mandaar Bhaskar Pande, Subhasish Dutta Gupta
A homogeneously broadened two-level ring laser with an intracavity parametric amplifier is studied. The presence of the parametric amplifier is shown to lead to two distinct nontrivial cw solutions compared to the one in its absence. The conditions for the stability of these cw solutions are obtained. It is shown that in the context of the resonant modes one cw solution is always phase stable, whereas the other is always phase unstable. For pump parameters beyond a critical value (the second threshold), both these cw solutions become amplitude unstable, and self-pulsing can set in. The shape and the velocity of these pulses are evaluated numerically. It is shown that two distinct types of steady-state pulses beyond the second laser threshold are possible due to the phase sensitivity introduced by the parametric amplifier. This is in sharp contrast to the case without the parametric amplifier, where only Risken-Nummedal pulses [see H. Risken and K. Nummedal, J. Appl. Phys. 39, 4662 (1968)] are possible. It is shown that the parametric amplifier can lead to the narrowing or broadening of the Risken-Nummedal pulses. Moreover, it is shown that the ring laser with or without the parametric amplifier allows for a pulsed solution distinct from the above-mentioned one, which, however, turns out to be unstable.
Physical Review A•Dec 1, 1992•2 citations