Squeezed states produced by modulation interaction and phase conjugation in fibers

Number-state expansions are derived for the squeezed states produced by four-wave mixing (modulation interaction and phase conjugation) in fibers. These expansions are valid for arbitrary pump-induced coupling and dispersion- and pump-induced mismatch coefficients. To illustrate their use, formulas are derived for the associated field-quadrature and photon-number variances and correlations.