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Light P.S.,University of Adelaide | Anstie J.D.,University of Adelaide | Benabid F.,CNRS XLIM Research Institute, Limoges | Luiten A.N.,University of Adelaide
Optics Letters | Year: 2015

We have built an optical-frequency standard based on interrogating iodine vapor that has been trapped within the hollow core of a hermetically sealed kagome-lattice photonic crystal fiber. A frequency-doubled Nd:YAG laser locked to a hyperfine component of the P(142)37-0 127I2 transition using modulation transfer spectroscopy shows a frequency stability of 3 × 10-11 at 100 s. We discuss the impediments in integrating this all-fiber standard into a fully opticalfiber- based system, and suggest approaches that could improve performance of the frequency standard substantially. © 2015 Optical Society of America. Source


Arnault F.,CNRS XLIM Research Institute, Limoges
Journal of Physics A: Mathematical and Theoretical | Year: 2012

We give a multidimensional generalization of the complete set of Bell-correlation inequalities given by Werner and Wolf (2001 Phys. Rev. A 64 032112) and by Zukowski and Brukner (2002 Phys. Rev. Lett. 88 210401), for the two-dimensional case. Our construction applies to the n-party, two-observable case, where each observable is d-valued. The inequalities obtained involve homogeneous polynomials. They define the facets of a polytope in a complex vector space of dimension d n. We detail the inequalities obtained in the case d = 3 and, from them, we recover known inequalities. We finally explain how the violations of our inequalities by quantum mechanics can be computed and could be observed, when using unitary observables. © 2012 IOP Publishing Ltd. Source


Roberg M.,TriQuint Semiconductor | Reveyrand T.,CNRS XLIM Research Institute, Limoges | Ramos I.,University of Colorado at Boulder | Falkenstein E.A.,Qualcomm | Popovic Z.,University of Colorado at Boulder
IEEE Transactions on Microwave Theory and Techniques | Year: 2012

This paper presents a theoretical analysis of harmonically terminated high-efficiency power rectifiers and experimental validation on a class-C single Schottky-diode rectifier and a class-F-1 GaN transistor rectifier. The theory is based on a Fourier analysis of current and voltage waveforms, which arise across the rectifying element when different harmonic terminations are presented at its terminals. An analogy to harmonically terminated power amplifier (PA) theory is discussed. From the analysis, one can obtain an optimal value for the dc load given the RF circuit design. An upper limit on rectifier efficiency is derived for each case as a function of the device on-resistance. Measured results from fundamental frequency source-pull measurement of a Schottky diode rectifier with short-circuit terminations at the second and third harmonics are presented. A maximal device rectification efficiency of 72.8% at 2.45 GHz matches the theoretical prediction. A 2.14-GHz GaN HEMT rectifier is designed based on a class-F-1 PA. The gate of the transistor is terminated in an optimal impedance for self-synchronous rectification. Measurements of conversion efficiency and output dc voltage for varying gate RF impedance, dc load, and gate bias are shown with varying input RF power at the drain. The rectifier demonstrates an efficiency of 85% for a 10-W input RF power at the transistor drain with a dc voltage of 30 V across a 98-Ω resistor. © 1963-2012 IEEE. Source


Benoist J.,CNRS XLIM Research Institute, Limoges
Journal of Global Optimization | Year: 2015

In this paper, we solve a conjecture proposed by Borwein and Sims (Fixed-point algorithms for inverse problems in science and engineering, Springer optimization and its applications, 2011) in a Hilbert space setting. For the simple non-convex example of the sphere and the line, the sequence of Douglas–Rachford iterates converges in norm to a point of the intersection except when the initial value belongs to the hyperplane of symmetry. © 2015, Springer Science+Business Media New York. Source


Huynh V.N.,Quy Nhon University | Nguyen H.T.,Quy Nhon University | Thera M.,CNRS XLIM Research Institute, Limoges
Mathematical Programming | Year: 2013

In this paper, we establish some new characterizations of metric regularity of implicit multifunctions in complete metric spaces by using lower semicontinuous envelopes of the distance functions to set-valued mappings. Through these new characterizations it is possible to investigate implicit multifunction theorems based on coderivatives and on contingent derivatives as well as the perturbation stability of implicit multifunctions. © 2013 Springer-Verlag Berlin Heidelberg and Mathematical Optimization Society. Source

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