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Pulsed Sagnac polarization-entangled photon source with a PPKTP crystal at telecom wavelength
- Source :
- Optics express. 22(10)
- Publication Year :
- 2014
-
Abstract
- We demonstrate pulsed polarization-entangled photons generated from a periodically poled $\mathrm{KTiOPO_4}$ (PPKTP) crystal in a Sagnac interferometer configuration at telecom wavelength. Since the group-velocity-matching (GVM) condition is satisfied, the intrinsic spectral purity of the photons is much higher than in the previous scheme at around 800 nm wavelength. The combination of a Sagnac interferometer and the GVM-PPKTP crystal makes our entangled source compact, stable, highly entangled, spectrally pure and ultra-bright. The photons were detected by two superconducting nanowire single photon detectors (SNSPDs) with detection efficiencies of 70% and 68% at dark counts of less than 1 kcps. We achieved fidelities of 0.981 $\pm$ 0.0002 for $\left| {\psi ^ -} \right\rangle$ and 0.980 $\pm$ 0.001 for $\left| {\psi ^ +} \right\rangle$ respectively. This GVM-PPKTP-Sagnac scheme is directly applicable to quantum communication experiments at telecom wavelength, especially in free space.<br />Comment: 5 pages, 5 figures http://dx.doi.org/10.1364/OE.22.011498
- Subjects :
- Quantum optics
Superconductivity
Physics
Quantum Physics
Photon
business.industry
Photon source
Nanowire
FOS: Physical sciences
Physics::Optics
Quantum key distribution
Quantum information processing
Polarization (waves)
Atomic and Molecular Physics, and Optics
Wavelength
Interferometry
Optics
Optoelectronics
Quantum information science
Telecommunications
business
Quantum Physics (quant-ph)
Spectral purity
Subjects
Details
- ISSN :
- 10944087
- Volume :
- 22
- Issue :
- 10
- Database :
- OpenAIRE
- Journal :
- Optics express
- Accession number :
- edsair.doi.dedup.....90fe5ad679532068a94935f810499b08