We describe an achromatic, phase-stable, broadband source of polarization-entangled photon pairs with high spectral brightness that uses four-wave mixing in a fiber Sagnac interferometer. We achieved a polarization-entangled two-photon coincidence rate of 7 kHz per 0.5 THz (0.9 nm) of bandwidth per 300 ?W of average pump power. At this rate, we observed two-photon fringe interference visibilities greater than 97%, over a 10 THz (? 24 nm) spectral range. We measured violations of Bell s inequality by more than 24 standard deviations for each of the four Bell states in less than 3 minutes per state. Our measurements demonstrate that this source possesses a high spectral brightness (7 kHz/300 ?W/0.9 nm), large tunable wavelength range (24 nm), single spatial mode, and phase stability, making it a promising candidate for a wide range of quantum-information applications.
Citation: Proceedings of SPIE
Pub Type: Journals
accidental, Bell state, coincidence, four-wave mixing, Raman scattering, Sagnac interferometer