Abstract

It has been theoretically shown^[1 that the pump beam reflected back from a triply resonant parametric oscillator may be significantly squeezed when working close to a bistability turning point, in a way similar to the situation encountered in a Kerr medium inserted in an optical cavity^[2]. This effect can be explained in the following way : the pump beam generates by χ⁽²⁾ parametric down-conversion signal and idler modes which remain essentially trapped in the OPO cavity, because of its high finesse. These signal and idler beams generate back, by χ⁽²⁾ sum-frequency mixing, the pump mode, which escapes the cavity and mixes with the directly reflected part of the pump field (cascading nonlinearity process). Like in a Ken-medium, this process gives rise to a squeezed beam on some quadrature component which is usually neither phase nor amplitude, and which rotates as a function of the cavity detuning.

© 1996 IEEE