  Recently demonstrated ghost interference using correlated photons of
different frequencies, has been theoretically analyzed. The calculation
predicts an interesting nonlocal effect: the fringe width of the ghost
interference depends not only on the wave-length of the photon involved, but
also on the wavelength of the other photon with which it is entangled. This
feature, arising because of different frequencies of the entangled photons, was
hidden in the original ghost interference experiment. This prediction can be
experimentally tested in a slightly modified version of the experiment.
