Virginia D'Auria

Continuous-variable entanglement of two bright coherent states that never interacted

We study continuous-variable entanglement of bright quantum states in a pair of evanescently coupled nonlinear

Towards high repetition rate operational quantum relay at telecom wavelength

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Ultra-fast photon pair sources for long-distance quantum communication

waveguides operating in the regime of degenerate down conversion. We consider the case where only the energy of the nonlinearly generated fields is exchanged between the waveguides while the pump fields stay independently guided in each original waveguide. We show that this device, when operated in the depletion regime, entangles the two noninteracting bright pump modes due to a nonlinear cascade effect. It is also shown that two-color quadripartite entanglement can be produced when certain system parameters are appropriately set. This device works in the traveling-wave configuration, such that the generated quantum light shows a broad spectrum. The proposed device can be easily realized with current technology and therefore stands as a good candidate for a source of bipartite or multipartite entangled states for the emerging field of optical continuous-variable quantum information processing.

Narrowband polarization entanglement sources based on integrated optics for quantum applications at telecom wavelength

Quantum entanglement, besides being a theoretical ground in quantum physics, is now considered as a key resource for the implementations of many complex quantum information science (QIS) protocols. One of the most investigated QIS protocols for long-distance quantum communication, involving entanglement as a genuine resource, is the entanglement swapping in quantum relay (QR) configuration. Alas, the quality of a QR is heavily affected by synchronization issues between remote entangled photon pair sources. In this paper, we present an all-optical, high repetition rate synchronization technique in picosecond regime, and demonstrate the realization of ultra-fast photon pair sources based on high-performance telecom components and nonlinear optics.

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

We report on the realization of ultra-fast photon pair sources for long-distance quantum relays. Our sources are capable to deliver high-quality single photon pairs at high repetition rate, guaranteeing efficient operational condition for intended protocol.

Ultra-fast heralded single photon source based on telecom technology

Polarization entangled photon pair sources based on either type-II or type-0 PPLN waveguides emitting at telecom wavelengths are presented. Implementation of such sources, associated high-quality entanglement, as well as related potential for future quantum applications are shown.

Quantum description of timing jitter for single-photon ON-OFF detectors

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.