  We theoretically study reflection and transmission of light in a
one-dimensional disordered phase-conjugating medium. Using an invariant
imbedding approach a Fokker-Planck equation for the distribution of the probe
light reflectance and expressions for the average probabilities of reflection
and transmission are derived. A new crossover length scale for localization of
light is found, which depends on the competition between phase conjugation and
disorder. For weak disorder, our analytical results are in good agreement with
numerical simulations.
