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ABSTRACT: We report an observation of parametric amplification with a gain greater than 30dB in a 1.7-m microstructure fiber. It is
found that there exists a peak pump power Ps. For peak pump powers less than Ps, the amplified twin (signal: longer wavelength, and idler: shorter wavelength) pulses are highly correlated, and the bandwidth
of the amplified signal pulse broadens monotonically with pump power. For peak pump powers exceeding Ps, the correlation between the amplified twin pulses drops when the pump power increases, the bandwidth of the amplified signal
pulse becomes narrower when the pump power increases, and the central wavelength of the amplified signal (idler) pulse shifts
towards longer (shorter) wavelength, respectively, due to phase matching.
Applied Physics B 04/2012; 81(6):801-805. · 2.19 Impact Factor
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ABSTRACT: We review the current status of single-photon-source and single-photon-detector technologies operating at wavelengths from the ultraviolet to the infrared. We discuss applications of these technologies to quantum communication, a field currently driving much of the development of single-photon sources and detectors.
The Review of scientific instruments 07/2011; 82(7):071101. · 1.52 Impact Factor
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ABSTRACT: We investigate a strategy for M-ary discrimination of nonorthogonal phase states with error rates below the homodyne limit. This strategy uses feed forward to update a reference field and signal nulling for the state discrimination. We experimentally analyze the receiver performance using postprocessing and a Bayesian strategy to emulate the feed-forward process. This analysis shows that for a moderate system detection efficiency, it is possible to surpass the homodyne error limit for quadrature phase-shift keying signals using feed forward.
Physical Review A 01/2011; 84:062324. · 2.88 Impact Factor
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ABSTRACT: We experimentally map the transverse profile of diffractionlimited beams using photon-number-resolving detectors.We observe strong compression of diffracted beam profiles for high detected photon number. This effect leads to higher contrast than a conventional irradiance profile between two Airy disk-beams separated by the Rayleigh criterion.
Optics Express 03/2010; 18(6):6033-9. · 3.59 Impact Factor
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ABSTRACT: We analyze the generation of single spatial mode, spectrally uncorrelated photon pairs via type II spontaneous parametric down-conversion in a Potassium Titanyl Phosphate (KTP) waveguide using real experimental parameters. We show that this source can be used as an efficient, heralded, pure-state single-photon source.
Optics Express 02/2010; 18(4):3708-18. · 3.59 Impact Factor
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ABSTRACT: Using photon pairs created via four-wave mixing in a microstructure fiber, we measure g<sup>(2)</sup>(0) of idler photons heralded by a signal photon to be well below one, and six times less than unconditional g<sup>(2)</sup>(0).
Lasers and Electro-Optics, 2008 and 2008 Conference on Quantum Electronics and Laser Science. CLEO/QELS 2008. Conference on; 06/2008
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ABSTRACT: We describe an experimental test of local realistic and nonlocal realistic theories using polarization-entangled two-photon singlet states created using a fiber-based polarization Sagnac interferometer. We show a violation of Bell’s inequality in the Clauser-Horne-Shimony-Holt form by 15 standard deviations, thus excluding local hidden-variable theories, and a violation of a Leggett-type nonlocal hidden-variable inequality by more than three standard deviations, thus excluding a class of nonlocal hidden-variable theories.
Phys. Rev. A. 03/2008; 77(3).
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ABSTRACT: We describe the creation and characterization of entangled or hyper-entangled quantum states using a fiber-based two-photon source. We use these entangled states to study local- and non-local realism.
Winter Topical Meeting Series, 2008 IEEE/LEOS; 02/2008
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ABSTRACT: 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.
Optics Express 01/2008; 15(26):18339-44. · 3.59 Impact Factor
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ABSTRACT: On coupling two phase-coherent frequency-conjugate laser pulses into a microstructure fiber, we observe phase-sensitive photon generation via four-wave mixing, and suppression of Raman emission at the middle frequency.
Optics Letters 10/2006; 31(18):2771-3. · 3.40 Impact Factor
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ABSTRACT: We report efficient generation of correlated photon pairs through degenerate four-wave mixing in a microstructure fiber. With 735.7 nm pump pulses producing correlated signal (688.5 nm) and idler (789.8 nm) photons in a 1.8 m microstructure fiber, we detect photon pairs at a rate of 37.6 kHz with a coincidence/ accidental contrast of 10:1 with deltalambda = 0.7 nm. This is the highest rate to our knowledge reported to date in a fiber-based photon source. The light source is highly nonclassical as defined by the Zou-Wang-Mandel inequality, which is violated by 1100 times the uncertainty.
Optics Letters 01/2006; 30(24):3368-70. · 3.40 Impact Factor
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ABSTRACT: We propose and experimentally demonstrate a new method of generating correlated photons in a microstructure fiber by means of a reversed degenerate four-wave-mixing process. Here one photon is annihilated from each of the bichromatic pump pulses to generate a pair of photons at the mean frequency. For a microstructure fiber as short as 1.5 m the measured coincidence counting rate is approximately eight times that of the accidental coincidences with a peak pump power of 0.25 W.
Optics Letters 07/2005; 30(12):1530-2. · 3.40 Impact Factor
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ABSTRACT: We proposed and demonstrated a new method to generate correlated photons in a microstructure fiber via a reversed degenerate four-wave-mixing process with a pair of laser pulse at conjugate frequencies.
Quantum Electronics and Laser Science Conference, 2005. QELS '05; 06/2005
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ABSTRACT: We demonstrate correlated photon-pair generation using four-wave mixing in micro-structured fiber. The anomalous group dispersion just above the zero-dispersion point ensures phase-matching. We obtained coincidence-counting rate significantly over the accidental counting rate.
Quantum Electronics and Laser Science, 2003. QELS. Postconference Digest; 07/2003
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ABSTRACT: 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 μW of average pump power. At this rate, we observed two-photon fringe interference visibilities greater than 97%, over a 10 THz (≈21 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 3 minutes per state. The high spectral brightness (26 kHz nm−1 mW−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.
Phys. Rev. A. 76(4).
