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

Author(s): A. Fedrizzi, T. Herbst, A. Poppe, T. Jennewein, A. Zeilinger

Journal: Optics Express

Volume: 15

Page(s): 15377-15386

Year: 2007

DOI Number: 10.1364/OE.15.015377

Link: Link to publication

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.

Note: http://arxiv.org/abs/0706.2877

File: Link to PDF

Zeilinger Group Zeilinger Group