We describe a stable type II optical parametric oscillator operated above threshold that provides 9.7±0.5 dB (89%) of quantum noise reduction on the intensity difference of the signal and idler modes. We also report the first experimental study, to our knowledge, by homodyne detection of the generated bright two-mode state in the case of frequency-degenerate operation obtained by the introduction of a birefringent plate inside an optical cavity.
© 2005 Optical Society of America
Julien Laurat, Laurent Longchambon, Claude Fabre, and Thomas Coudreau, "Experimental investigation of amplitude and phase quantum correlations in a type II optical parametric oscillator above threshold: from nondegenerate to degenerate operation," Opt. Lett. 30, 1177-1179 (2005)