  We experimentally study Bragg-scattering four-wave mixing in a highly
nonlinear fiber at telecom wavelengths using photon counters. We explore the
polarization dependence of this process with a continuous wave signal in the
macroscopic and attenuated regime, with a wavelength shift of 23 nm. Our
measurements of mean photon numbers per second under various pump polarization
configurations agree well with the theoretical and numerical predictions based
on classical models. We discuss the impact of noise under these different
polarization configurations.
