  We study a generalized notion of two-mode squeezing for the Stokes and
anti-Stokes fields in a model of a cavity Raman laser, which leads to a
significant reduction in decoherence or quantum noise. The model comprises a
loss-less cavity with classical pump, unsaturated medium and arbitrary
homogeneous broadening and dispersion. Allowing for arbitrary linear
combinations of the two modes in the definition of quadrature variables, we
find that there always exists a combination of the two output modes which
exhibits quadrature squeezing with noise reduction below the vacuum level. The
number of noise photons for this combination mode is proportional to the square
root of the number of Stokes noise photons.
