Pulsed source of spectrally uncorrelated and indistinguishable photons at telecom wavelengths

Abstract

We report on the generation of indistinguishable photon pairs at telecom wavelengths based on a type-II parametric down conversion process in a periodically poled potassium titanyl phosphate (PPKTP) crystal. The phase matching, pump laser characteristics and coupling geometry are optimised to obtain spectrally uncorrelated photons with high coupling efficiencies. Four photons are generated by a counter-propagating pump in the same crystal and anlysed via two photon interference experiments between photons from each pair source as well as joint spectral and g (2) measurements. We obtain a spectral purity of 0.91 and coupling efficiencies around 90% for all four photons without any filtering. These pure indistinguishable photon sources at telecom wavelengths are perfectly adapted for quantum network demonstrations and other multi-photon protocols.

Temporal Purity and Quantum Interference of Single Photons from Two Independent Cold Atomic Ensembles

“…In this case, the temporal state of the single photons relies on the spectral property of the external passive filter or optical cavity, which is monolithic and unavailable to be manipulated. On the other hand, to avoid filtering and produce a bright single-photon source, the spectral correlation can be removed through engineering the SPDC source [19][20][21][22][23]. The factorable joint amplitude for the signal and idler photons is necessary to guarantee a pure single-photon state.…”

Monotonic quantum-to-classical transition enabled by positively correlated biphotons

“…The spectrally uncorrelated JSA in Fig. 2(a1) can be generated by filtering a PPKTP downconversion source at 1584 nm [29][30][31]. The spectrally negatively correlated JSA in Fig.…”

Spectrally Pure States at Telecommunications Wavelengths from Periodically PoledMTiOXO4(M=Jin1, Zhao2, Deng3 et al. 2016Phys. Rev. Applied210150View full textAdd to dashboardCite

“…It is also interesting to consider the spatial correlation, since the spectral purity can be further improved by spatial filtering [16,37,38]. As reported in Ref.…”

“…Recently, the study of spectrally pure state generation in a PPKTP crystal has achieved significant progress [11][12][13][14][15][16]. Besides high spectral purity, the PPKTP crystal still have several other merits, such as high brightness (because the crystal can be very long, thanks to the periodically poling technique), high damage threshold (higher than PPLN crystal), wide tunability (more than 200 nm at telecom wavelengths [14]).…”