Amandine Issautier

A polarization entangled photon-pair source based on a type-II PPLN waveguide emitting at a telecom wavelength

We report the realization of a fiber-coupled polarization entangled photon-pair source at 1310 nm based on a birefringent titanium in-diffused waveguide integrated into periodically poled lithium niobate. By making use of a dedicated and high-performance setup, we characterized the quantum properties of the pairs by measuring two-photon interference in both Hong–Ou–Mandel and standard Bell inequality configurations. For the two sets of measurements we obtained interference net visibilities reaching nearly 100%, which represent important and competitive results compared to those for the similar waveguide-based configurations already reported. These results prove the relevance of our approach as an enabling technology for long-distance quantum communication.

Toward Continuous-Wave Regime Teleportation for Light Matter Quantum Relay Stations

We report a teleportation experiment involving narrowband entangled photons at 1560 nm and qubit photons at 795 nm emulated by faint laser pulses. A nonlinear difference frequency generation stage converts the 795-nm photons to 1560 nm in order to enable interference with one photon out of the pairs, i.e., at the same wavelength. The spectral bandwidth of all involved photons is of about 25 MHz, which is close to the emission bandwidth of emissive quantum memory devices, notably those based on ensembles of cold atoms and rare earth ions. This opens the route toward the realization of hybrid quantum nodes, i.e., combining quantum memories and entanglement-based quantum relays exploiting either a synchronized (pulsed) or a asynchronous (continuous-wave) scenario.

Analysis of elliptically polarized maximally entangled states for bell inequality tests

When elliptically polarized maximally entangled states are considered, i.e., states having a non random phase factor between the two bipartite polarization components, the standard settings used for optimal violation of Bell inequalities are no longer adapted. One way to retrieve the maximal amount of violation is to compensate for this phase while keeping the standard Bell inequality analysis settings. We propose in this paper a general theoretical approach that allows determining and adjusting the phase of elliptically polarized maximally entangled states in order to optimize the violation of Bell inequalities. The formalism is also applied to several suggested experimental phase compensation schemes. In order to emphasize the simplicity and relevance of our approach, we also describe an experimental implementation using a standard Soleil-Babinet phase compensator. This device is employed to correct the phase that appears in the maximally entangled state generated from a type-II nonlinear photon-pair source after the photons are created and distributed over fiber channels.

Polarization entangled photon-pair source based on a type-II PPLN waveguide emitting at a telecom wavelength

We report the realization of a fiber coupled polarization entangled photon-pair source at 1310 nm based on a birefringent titanium in-diffused waveguide integrated on periodically poled lithium niobate. By taking advantage of an original setup, we characterized the quantum properties of the pairs by measuring two-photon interference in both Hong-Ou-Mandel and standard Bell inequality configurations. We obtained, for the two sets of measurements, interference net visibilities reaching nearly 100 %, which represent the best results ever reported for similar waveguide-based configurations. These results prove the relevance of our approach as an enabling technology for long-distance quantum communication.

Polarization entanglement engineering at telecom wavelengths

We report an efficient polarization entanglement engineering scheme based on a stabilized birefringent delay line. The scheme is capable of handling ultra narrowband photons making it compatible for multiplexing and quantum memory based applications.

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

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.