  The dependence of one- and two-photon characteristics of pulsed entangled
two-photon fields generated in spontaneous parametric down-conversion on the
pump-pulse properties (shape of the pump-pulse spectrum and its internal
structure) is examined. It is shown that entangled two-photon fields with
defined properties can be generated. A general relation between the spectra of
the down-converted fields is established. As a special case interference of two
partially overlapping pulsed two-photon fields is studied. Fourth-order
interference pattern of entangled two-photon fields is investigated in the
polarization analog of the Hong-Ou-Mandel interferometer.
