We have demonstrated a bright single-mode-fiber source of polarization-entangled photon pairs with visibility > 97% and fidelity > 95% at a detected coincidence rate of 7 kHz/nm over a 3 dB, 10THz bandwidth.
We report an experimental demonstration of a bright high-fidelity single-mode-optical-fiber source of polarization-entangled photon pairs. The source takes advantage of single-mode fiber optics, highly nonlinear microstructure fiber, judicious phase-matching, and the inherent stability provided by a Sagnac interferometer. With a modest average pump power (300 microW), we create all four Bell states with a detected two-photon coincidence rate of 7 kHz per bandwidth of 0.9 nm, in a spectral range of more than 20 nm. To characterize the purity of the states produced by this source, we use quantum-state tomography to reconstruct the corresponding density matrices, with fidelities of 95 % or more for each Bell state.
We describe the preparation of a high spectral brightness, broad wavelength coverage, single-spatial mode source of polarization-entangled photon pairs operated at room temperature. The source takes advantage of single-mode fiber optics, highly nonlinear microstructure fiber, judicious phase-matching, and the inherent stability provided by a Sagnac interferometer. With a modest average pump power (300 μW), we create all four Bell states with a detected two-photon coincidence rate of 7 kHz per bandwidth of 0.9 nm, in a spectral range of more than 20 nm.
We describe the preparation of a high spectral brightness, broad wavelength coverage, single-spatial mode source of polarization-entangled photon pairs operated at room temperature. The source takes advantage of single-mode fiber optics, highly nonlinear microstructure fiber, judicious phase-matching, and the inherent stability provided by a Sagnac interferometer. With a modest average pump power (300 μW), we create all four Bell states with a detected two-photon coincidence rate of 7 kHz per bandwidth of 0.9 nm, in a spectral range of more than 20 nm.
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 7kHz per 0.5THz(0.9nm) of bandwidth per $300\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{W}$ of average pump power. At this rate, we observed two-photon fringe interference visibilities greater than 97%, over a 10THz $(\ensuremath{\approx}21\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ spectral range. We measured violations of Bell's inequality by more than 22 standard deviations for each of the four Bell states in less than 3minutes per state. The high spectral brightness $(26\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}\phantom{\rule{0.2em}{0ex}}{\mathrm{nm}}^{\ensuremath{-}1}\phantom{\rule{0.2em}{0ex}}{\mathrm{mW}}^{\ensuremath{-}1})$, large tunable wavelength range, single spatial mode, and phase stability make this source a promising candidate for a wide range of quantum-information applications.
We report the development of a fiber-based single-spatial-mode source of photon-pairs where the efficiency of extracting photon pairs is 14× higher than a previous implementation [16]. This critical improvement in efficiency enabled a spectrally bright and pure photon-pair source having a small second-order correlation function (0.03) and a raw spectral brightness of 44,700 pairs/(s nm mW). The source can be configured to generate entangled photon-pairs, characterized via optimal and minimal quantum state tomography, to have a fidelity of 97% and tangle of 92%, without correcting for accidentals.