Generation of high-purity telecom-band entangled photon pairs in dispersion-shifted fiber.
We study the purity of correlated photon pairs generated in a dispersion-shifted fiber at various temperatures. The ratio of coincidence to accidental-coincidence counts greater than 100 can be obtained as the fiber is cooled to liquid-nitrogen temperature (77 K). We then generate polarization-entangled photon pairs by using a compact counterpropagating scheme. Two-photon interference with visibility >98% and Bell's inequality violation by >8 standard deviations of measurement uncertainty are observed at 77 K, without subtracting the accidental-coincidence counts due to background Raman photons.
Lee
Kim Fook
KF
Department of Electrical Engineering and Computer Science, Center for Photonic Communication and Computing, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. kflee@ece.northwestern.edu
Chen
Jun
J
Liang
Chuang
C
Li
Xiaoying
X
Voss
Paul L
PL
Kumar
Prem
P