TRANSVERSE-MODE COUPLING IN A KERR MEDIUM

We analyze nonlinear transverse mode coupling in a Kerr medium placed in an optical cavity and its influence on bistability and different ki nds of quantum noise reduction. Even for an input beam that is perfect ly matched to a cavity mode, the nonlinear coupling produces an excess noise in the fluctuations of the output beam. Intensity squeezing see ms to be particularly robust with respect to mode coupling, while quad rature squeezing is more sensitive. However, it is possible to find a mode whose quadrature squeezing is not affected by the coupling.