In our paper we consider the non-classical behaviour of both the Hermitian
(observable) Stokes parameters of light and the phase difference of two mod
es that describe the quantum polarization states of optical field. To chara
cterize the degree of polarization of light we introduce a new quantity tak
ing into account the quantum properties of different quantum states of two
orthogonally polarized modes. The problem of determination of the phase dif
ference in two modes of optical field for the quantum polarization states o
f light is discussed. To describe in general such a quantum field we introd
uce two pairs of the phase operators: the phase angles for the Stokes param
eters of light in a three-dimensional picture of the Poincare sphere. We al
so consider a special type of the eight-port polarization interferometer (p
olarimeter) for simultaneous homodyne detection of both the Stokes paramete
rs of light and the polarization phase operators and their fluctuations as
well. Using an anisotropic (spatioperiodic) Kerr-like nonlinear medium asso
ciated with the polarization interferometer we could generate and also obse
rve the polarization-squeezed phase states of light. The fluctuations in th
e phase difference between two orthogonally polarized modes for these non-c
lassical states are less than the fluctuations for light in coherent state.