Theory of quantum fluctuations of optical dissipative structures and its application to the squeezing properties of bright cavity solitons

摘要

We present a method for the study of quantum fluctuations of dissipativestructures forming in nonlinear optical cavities, which we illustrate in thecase of a degenerate, type I optical parametric oscillator. The method consistsin (i) taking into account explicitly, through a collective variabledescription, the drift of the dissipative structure caused by the quantumnoise, and (ii) expanding the remaining -internal- fluctuations in thebiorthonormal basis associated to the linear operator governing the evolutionof fluctuations in the linearized Langevin equations. We obtain generalexpressions for the squeezing and intensity fluctuations spectra. Then wetheoretically study the squeezing properties of a special dissipativestructure, namely, the bright cavity soliton. After reviewing our previousresult that in the linear approximation there is a perfectly squeezed modeirrespectively of the values of the system parameters, we consider squeezing atthe bifurcation points, and the squeezing detection with a plane--wave localoscillator field, taking also into account the effect of the detector size onthe level of detectable squeezing.