  We propose a method of an improving quality of a ring cavity which is
imperfect due to non-unit mirror reflectivity. The method is based on using
squeezed states of light pulses illuminating the mirror and gradual homodyne
detection of a radiation escaping from the cavity followed by single
displacement and single squeezing operation performed on the released state. We
discuss contribution of this method in process of storing unknown coherent and
known squeezed state and generation of squeezing in the optical ring cavities.
