Fully fibred polarization entangled photon pair source at a telecom wavelength for long distance quantum networking

In this paper we present the experimental results obtained on a new fully fibred polarization entangled photon-pair source at a telecom wavelength (1560 nm). Photon pairs are created using a type-0 interaction in a periodically poled lithium niobate waveguide, which has been shown to be the most efficient for non linear crystals [1]. Polarization entanglement is then generated using a polarization dependent fibre delay line. Compared to a similar configuration reported previously [2], we obtain much higher visibilities on the violation of the Bell inequalities (≥ 97%), due to active delay line stabilization. In addition we remove the stringent constraint on the exact delay line length.