Highly nondegenerate polarization-entangled photon pairs produced through noncritical phasematching in single-domain KTiOPO${}_4$

Abstract

Photon-pair sources are useful for entanglement distribution. The most mature of these are spontaneous parametric downconversion (SPDC) sources, most of which achieve phasematching via engineering the domains in poled crystals or the angle between the optic axis and the pump beam. For multi-channel entanglement distribution of photon pairs, where one photon is transmitted through free-space and the other photon is transmitted through fiber, it is beneficial to use highly nondegenerate photon-pair sources. The currently accepted approach in such sources is quasi-phasematching. In this paper, a simpler, more stable alternative is presented for producing highly nondegenerate photon pairs. A source of polarization-entangled photon pairs with low temperature sensitivity based on noncritical phasematched (NCPM) SPDC in single-domain potassium titanyl phosphate (KTP) was demonstrated. Over a crystal temperature range of $75^{\circ }$C, the center wavelength of the idler photons was observed to change by $10.8$nm while the average entanglement visibility was maintained above $98\%$. With the signal photons detected locally, the idler photons were transmitted through 62km and 93km of deployed telecom fibers with average raw visibilities of $98.2(1)\%$ and $95.6(3)\%$ respectively.

8 pages, 7 figures

References in corpus (17)

• Photonic quantum technologies
• A wavelength-tunable fiber-coupled source of narrowband entangled photons
• Progress in satellite quantum key distribution
• Ultrathin quantum light source enabled by a nonlinear van der Waals crystal with vanishing interlayer-electronic-coupling
• Fiber-assisted single-photon spectrograph
• Entangled Photon-Pair Sources based on three-wave mixing in bulk crystals
• Optimal Co-linear Gaussian Beams for Spontaneous Parametric Down-Conversion
• Drone-based all-weather entanglement distribution
• Passively stable distribution of polarisation entanglement over 192 km of deployed optical fibre
• Collinear source of polarization-entangled photon pairs at non-degenerate wavelengths
• Stable Polarization Entanglement based Quantum Key Distribution over Metropolitan Fibre Network
• Experimental wavelength-multiplexed entanglement-based quantum cryptography
• Practical quantum imaging with undetected photons
• Photonic entanglement as a resource in quantum computation and quantum communication
• Experimental conversion of position correlation into polarization entanglement
• Distributing Polarization Entangled Photon Pairs with High Rate over Long Distance through Standard Telecommunication Fiber
• Robust and bright polarization-entangled photon sources exploiting non-critical phase matching without periodic poling

Cited by in corpus (1)

• Highly Efficient and Broadband Optical Delay Line towards a Quantum Memory