Theory of self-phase-locked optical parametric oscillators - art. no. 023814

The plane-wave dynamics of 3 omega --> 2 omega,omega subharmonic optical pa rametric oscillators containing a second-harmonic generator of the idler-wa ve w is analyzed analytically by using the mean-field approximation and num erically by taking into account the field propagation inside the media. The resonant chi ((2))(-3 omega ;2 omega, omega):chi ((2))(-2 omega;omega,omeg a) cascaded second-order nonlinearities induce a mutual injection locking o f the signal and idler waves that leads to coherent self-phase locking of t he pump and subharmonic waves, freezing the phase diffusion noise. In case of signal-and-idler resonant devices, largely detuned subthreshold states o ccur due to a subcritical bifurcation, broadening out the self-locking freq uency range to a few cavity linewidths.