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arXiv · quant-ph/0107125

PPLN Waveguide for Quantum Communication

S. Tanzilli·H. de Riedmatten·W. Tittel·H. Zbinden·P. Baldi·M. de Micheli·D. B. Ostrowsky·N. Gisin
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Abstract

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 1314 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. 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

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S. Tanzilli, H. de Riedmatten, W. Tittel, H. Zbinden, P. Baldi, M. de Micheli, D. B. Ostrowsky, N. Gisin. 2001-07-25. PPLN Waveguide for Quantum Communication. https://doi.org/10.1140/epjd%2Fe20020019

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