Philippe Emplit

Photon pair source based on parametric fluorescence in periodically poled twin-hole silica fiber

We present observations of quasi-phase matched parametric fluorescence in a periodically poled twin-hole silica fiber. The phase matching condition in the fiber enables the generation of a degenerate signal field in the fiber-optic communication band centered on 1556 nm. We performed coincidence measurements and a Hong-Ou-Mandel experiment to validate that the signal arises from photon pairs. A coincidence peak with a signal to noise ratio (SNR) of 4 using 43 mW of pump power and a Hong-Ou-Mandel dip showing 40% net visibility were measured. Moreover, the experiments were performed with standard single mode fibers spliced at both ends of the poled section, which makes this source easy to integrate in fiber-optic quantum communication applications.

Creating and manipulating entangled optical qubits in the frequency domain

Dx13epartement d’Optique P. M. Dux0eeux, Institut FEMTO{ST, Unitx13e Mixte de Recherche du CNRS 6174,Universitx13e de Franche-Comtx13e, route de Gray 16, Besan˘con F-25030, France(Dated: March 5, 2014)Radio-frequency phase modulation of frequency entangled photons leads to a two-photon inter-ference pattern in the frequency domain. In recent experiments, the pattern was measured withnarrow-band frequency lters which select photons belonging to a given frequency bin. Here weshow how photons can be grouped into even and odd frequencies by using periodic frequency lterscalled interleavers. In our theoretical analysis we show how this reduces the high-dimensional pho-ton state to an e ective two-dimensional state. This is of interest for applications such as quantumcryptography or low-dimensional tests of quantum nonlocality. We then report an experimentalrealization of this proposal. The observed two-photon interference pattern and violation of theCHSH inequality { the simplest binary-outcome Bell inequality { are in good agreement with thetheoretical predictions.

Manipulating frequency entanglement with phase modulators

A parametric down conversion source pumped by a monochromatic laser will produce frequency entangled photon pairs. We demonstrate this by an experiment in which five-dimensional frequency entanglement is manipulated at telecommunication wavelengths using commercially available components such as electro-optic phase modulators and narrowband frequency filters. A theoretical intuition for this approach is developed by introducing the notion of frequency bin entanglement. We conclude by showing that using this method one can in principle violate the CHSH, the CGLMP, and a new – as yet unnamed – Bell inequalities.

Propagation and survival of frequency-bin entangled photons in metallic nanostructures

Abstract We report on the design of two plasmonic nanostructures and the propagation of frequency-bin entangled photons through them. The experimental findings clearly show the robustness of frequency-bin entanglement, which survives after interactions with both a hybrid plasmo-photonic structure, and a nano-pillar array. These results confirm that quantum states can be encoded into the collective motion of a many-body electronic system without demolishing their quantum nature, and pave the way towards applications of plasmonic structures in quantum information.

Two-photon experiments in the frequency domain

We report on the study of two-photon interference in the frequency domain. Bell and Hong-Ou-Mandel experiments are investigated. These experiments involve the manipulation of photons in the frequency domain, using off-the-shelf telecommunication components such as electro-optic phase modulators and narrow-band frequency filters. In the first experiment, photon pairs entangled in frequency are created and separated. Each photon is then directed through an independent electro-optic phase modulator. Variation of the radio-frequency parameters of the modulation gives rise to a well-controlled Bessel-shape two-photon interference pattern in the frequency domain. This is efficiently measured with narrow-band frequency filters and superconducting single photon detectors. Experimental measurements exhibit high visibilities (over 99 percent both for net and raw visibilities) and allow the (theoretically proven) optimal violation of a Bell inequality for our setup (by more than 18 standard deviations). The second experiment is a Hong-Ou-Mandel experiment in the frequency domain. We show that a grating (spatial domain) or a phase modulator (temporal domain) can be seen as a frequency beam splitter. A broadband spectrum of photon pairs is divided into two interleaved frequency combs, each one used as an independent input to this acting beam splitter. A theoretical calculation shows clear photon anti-bunching behavior.

Manipulating Frequency Entangled Photons

A parametric down conversion source pumped by a monochromatic laser will produce frequency entangled photon pairs. We demonstrate this by an experiment in which five-dimensional frequency entanglement is manipulated at telecommunication wavelengths using commercially available components such as electro-optic phase modulators and narrowband frequency filters. A theoretical intuition for this approach is developed by introducing the notion of frequency bin entanglement. We conclude by showing that using this method one can in principle violate the CHSH, the CGLMP, and a new – as yet unnamed – Bell inequalities.

Photon pair source based on periodically poled twin-hole silica fibre

In this paper we report the experimental observation of photon pair generation in periodically poled twin-hole silica fibre. Compared with periodically poled D-shape fibres, twin-hole fibres have important advantages: direct splicing to standard fibres is possible; as well as periodic poling technology compatible with tens of centimetres of interaction length, thus potentially ensuring higher conversion.