Evaluation of Polarization Mode Dispersion and Chromatic Dispersion   using Quantum Interferometry
  The use of quantum correlations between photons to measure polarization mode dispersion (PMD) and chromatic dispersion is investigated. Two types of apparatus are discussed which use coincidence counting of entangled photon pairs to allow sub-femtosecond resolution for measurement of both PMD and chromatic dispersion, as well as separation of even-order and odd-order chromatic effects in the PMD. Group delays can be measured with a resolution of order 0.1 fs, whereas attosecond resolution can be achieved for phase delays. 
A. Fraine, D.S. Simon, O. Minaeva, R. Egorov, A.V. Sergienko
quant-ph physics.optics