Twin beams correlation and single beam noise for triply resonant KTP OPOs

Triply resonant optical parametric oscillations (TRO) are of interest for generating stable and highly correlated twin beams. Here we report intensity noise correlation and single beam spectra for pump powers up to 14 times the threshold value. The correlation spectrum appear to be independent of the pump power while the single beams exhibit a peak due to relaxation oscillation. Such a resonance contributes to mask the squeezing predicted for double resonant devices. The herein discussed TRO has shown a temporal stability of the pump resonance longer than 6 h while delivering up to 4 mW per beam, fluctuating less than 5% over periods longer than half an hour.