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

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

Publications: Contribution to journalArticlePeer Reviewed


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. © 2007 Optical Society of America.
Original languageEnglish
Pages (from-to)15377-15386
Number of pages10
JournalOptics Express
Issue number23
Publication statusPublished - 2007

Austrian Fields of Science 2012

  • 103026 Quantum optics


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