  We report an experimental study of group-velocity dispersion effect on an
entangled two-photon wavepacket, generated via spontaneous parametric
down-conversion and propagating through a dispersive medium. Even in the case
of using CW laser beam for pump, the biphoton wavepacket and the second-order
correlation function spread significantly. The study and understanding of this
phenomenon is of great importance for quantum information applications, such as
quantum communication and distant clock synchronization.
