  Dispersion and its cancellation in entanglement-based nonlocal quantum
measurements are of fundamental and practical interests. We report the first
demonstration of cancellation of femtosecond-level dispersion by inverting the
sign of the differential dispersion between the long and short paths in only
one arm of a fiber-based Franson interferometer. We restore the otherwise
limited quantum visibility to an unprecedented 99.6%, and put time-energy
entanglement at the same level of quality as polarization entanglement for use
in quantum information processing applications.
