  The photon-induced process of electron-positron pair creation in a strong
homogeneous magnetic field, provided that the polarization of particles is
arbitrary, has been considered. The polarization of a photon is described in
terms of the well-known Stokes parameters, and the relevant probabilities of
the process turn out to have simple analytical expressions, which allows us to
analyze the polarization and spin effects. A substantial influence of the
linear polarization of a photon on the spin orientations of electrons and
positrons has been demonstrated.
