A wavelength-tunable fiber-coupled source of narrowband entangled photons

Alessandro Fedrizzi, Thomas Herbst, Andreas Poppe, Thomas Jennewein, Anton Zeilinger

Research output: Contribution to journalArticle

290 Citations (Scopus)

Abstract

We demonstrate a wavelength-tunable, fiber-coupled source of polarization-entangled photons with extremely high spectral brightness and quality of entanglement. Using a 25 mm PPKTP crystal inside a polarization Sagnac interferometer we detect a spectral brightness of 273000 pairs (s mW nm)(-1), a factor of 28 better than comparable previous sources while state tomography showed the two-photon state to have a tangle of T = 0.987. This improvement was achieved by use of a long crystal, careful selection of focusing parameters and single-mode fiber coupling. We demonstrate that, due to the particular geometry of the setup, the signal and idler wavelengths can be tuned over a wide range without loss of entanglement.

Original languageEnglish
Pages (from-to)15377-15386
Number of pages10
JournalOptics Express
Volume15
Issue number23
DOIs
Publication statusPublished - 12 Nov 2007

Keywords

  • PARAMETRIC DOWN-CONVERSION
  • QUANTUM COMMUNICATION
  • PAIRS
  • CRYPTOGRAPHY
  • KTIOPO4
  • CRYSTAL
  • STATE
  • LIGHT
  • KTP

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