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.
@article{arxiv.1308.3545,
title = {Nonlocal cancellation of dispersion in Franson interferometry},
author = {Tian Zhong and Franco N. C. Wong},
journal= {arXiv preprint arXiv:1308.3545},
year = {2015}
}