  We present the first observation of two-photon polarization interference
structure in the second-order Glauber's correlation function of two-photon
light generated via type-II spontaneous parametric down-conversion. In order to
obtain this result, two-photon light is transmitted through an optical fibre
and the coincidence distribution is analyzed by means of the START-STOP method.
Beyond the experimental demonstration of an interesting effect in quantum
optics, these results also have considerable relevance for quantum
communications.
