  The Stokes parameters of the pulsed synchrotron radiation produced in the
striped pulsar wind model are computed and compared with optical observations
of the Crab pulsar. We assume the main contribution to the wind emissivity
comes from a thin transition layer where the dominant toroidal magnetic field
reverses its polarity. The radial component of the field is neglected, but a
small meridional component is added. The resulting radiation is linearly
polarized (Stokes V=0). In the off-pulse region, the electric vector lies in
the direction of the projection on the sky of the rotation axis of the pulsar.
This property is unique to the wind model and in good agreement with the data.
Other properties such as a reduced degree of polarization and a characteristic
sweep of the polarization angle within the pulses are also reproduced. These
properties are qualitatively unaffected by variations of the wind Lorentz
factor, the electron injection power law index and the inclination of the line
of sight.
