Experimental wavelength-division-multiplexed photon-pair distribution

Abstract

Compiled 10 février 2018We have experimentally implemented the distribution of photon pairs produced by spontaneous parametric down conversion through telecom dense wavelength division multiplexing filters. Using the measured counts and coincidences between symmetric channels, we evaluate the maximum fringe visibility that can be obtained with polarization entangled photons and compare different filter technologies. c 2018 Optical Society of America OCIS codes: 060.5565, 060.2340, 060.4265.In order to be truly useful for technological applications, future quantum communication networks will require a large number of high quality entangled photon pair sources. An attractive way to reduce the associated cost is to use the wide spectrum produced by spontaneous parametric down conversion (SPDC) in combination with standard off-the-shelf dense wavelength division multiplexing (DWDM) filters to distribute nondegenerate photon pairs to a large number of users. It is then an important task to test photon pair sources in a WDM environment with various types of filters, in order to unveil filter characteristics that are necessary to obtain sources featuring high visibility while maintaining a useful brightness. Among previous works based on the idea of DWDM distribution of photon pairs [1-4], Lim et al [1] performed a proof-of-principle experiment using a dichroic mirror to separate the two photons of the pair and tunable filters on each channel to simulate the demultiplexing operation. Furthermore, a wavelength selective switch, based on arrayed waveguide grating technology, was tested in [2]. Frequency dependent losses were taken into account to explain the experimental coincidence probabilities, however the system required a different tuning of the pump for distribution over the various channel pairs, hence it could not be simultaneously multi-user in that configuration. In this work, we compare various DWDM filters with respect to the quality of a photon pair source with the ultimate goal of determining the filter performances required for quantum communication applications. The WDM photon pair distribution device is based on the energy conservation condition of spontaneous parametric down conversion : if ω p is the pump frequency, then the frequencies of the signal and idler photons ω s and ω i are symmetric with respect to ω p /2. The idea then is to tune the degeneracy frequency ω p /2 to the central frequency of the filter, so that the signal and idler photons can be transmitted by symmetric channel pairs. The users that will receive the two photons of an entangled pair can be determined by using a standard telecom switching device. If we wanted each user to receive a given channel permanently, then distributing entanglement, for instance, to Alice (ω A ) and Bob (ω B ), would mean tuning the pump frequency to ω A + ω B .Commercial optical demultiplexing filters are based on three main technologies [5] : (a) dielectric thin-film filters (DTF), consisting of Fabry-Perot cavities and quarter wavelength layers ; thes...

High-Efficiency Plug-and-Play Source of Heralded Single Photons

“…Many integrated quantum devices have been fabricated, ranging from waveguide sources [1][2][3][4][5][6] and entanglement sources [7][8][9][10][11][12] to on-chip detectors [13,14], from quantum teleporters [15] to complex linear circuits [16] with photonic manipulation [17]. However, the functioning of these circuits still relies on the careful alignment of external bulk components, limiting usefulness outside the lab.…”

Multi-user distribution of polarization entangled photon pairs

“…This possibility has been explored in several recent works [22][23][24][25][26] , while further work is in progress to integrate these devices 27 and to design flexible optical networks based on such sources 28 . In view of the wide use of wavelength division multiplexing in quantum networks for practical applications, it is essential to be able to properly test the employed demultiplexing technologies and quantify their effect to the quality of the distributed entanglement 29 . In this work, we demonstrate the distribution of polarization entangled photons using three different technologies and provide quality factors that are derived from classical characterization of these devices and that can be used to assess the quality of the obtained quantum correlations.…”

Actively switchable nondegenerate polarization-entangled photon-pair distribution in dense wave-division multiplexing

“…This source is different from a traditional source obtained by post-selecting cross-sections of two rings [7]. Our source is also different fro m schemes shown in Refs,1,2,5,[8][9][10][11][12][13][14], where either two nonlinear crystals [5,8,9] or an interferometer [1,2,[10][11][12][13][14] configuration are needed, which are rather com plex. Another point we want to mention is that although this source seems similar to scheme shown in Ref.…”

“…A combination of this technique with a photon source prepared by the spontaneously param etric down conversion (SP DC) can help one to distribute entangled non-degenerate photon pairs to a large number of users, which is a key step for building a quantum network. There are some reported works related to the combination of DWDM and photon pairs [1][2][3][4][5]. Jiang et al [1] used a coarse WDM to generate two non-degenerate polarization entangled photon pairs.…”

“…Moreover, a passive wavelength selective switch, based on arrayed waveguide grating technology, was tested in [3]. Most of the previous works use the photon with the spectral bandwidth of tens of nanom eters [1][2][3]5], and entanglement exists in channel pairs symm etric to the center of the emission spectrum. These schemes can realize the photon pair distribution in a channel pair passively using DWDM, but it is difficult to control and switch actively the photon pair distribution between different channel pairs.…”