https://doi.org/10.1140/epjd/e20020019
PPLN waveguide for quantum communication
1
Laboratoire de Physique de la Matière
Condensée (UMR 6622 du CNRS) , Université de Nice-Sophia
Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
2
Group of
Applied Physics, Université de Genève, 20 rue de
l'École-de-Médecine, 1211 Geneva 4, Switzerland
Corresponding author: a tanzilli@unice.fr
Received:
13
July
2001
Published online: 15 February 2002
We report on energy-time and time-bin entangled photon-pair sources based on a periodically poled lithium niobate (PPLN) waveguide. Degenerate twin photons at 1 314 nm wavelength are created by spontaneous parametric down-conversion and coupled into standard telecom fibers. Our PPLN waveguide features a very high conversion efficiency of about 10-6, roughly 4 orders of magnitude more than that obtained employing bulk crystals [1]. Even if using low power laser diodes, this engenders a significant probability for creating two pairs at a time – an important advantage for some quantum communication protocols. We point out a simple means to characterize the pair creation probability in case of a pulsed pump. To investigate the quality of the entangled states, we perform photon-pair interference experiments, leading to visibilities of 97% for the case of energy-time entanglement and of 84% for the case of time-bin entanglement. Although the last figure must still be improved, these tests demonstrate the high potential of PPLN waveguide based sources to become a key element for future quantum communication schemes.
PACS: 42.65.Wi – Nonlinear waveguides / 03.65.Ud – Entanglement and quantum nonlocality (e.g. EPR paradox, Bell's inequalities, GHZ states, etc.) / 03.67.Hk – Quantum communication
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
