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Politi A.,University of Bristol | Matthews J.C.F.,University of Bristol | Laing A.,University of Bristol | Peruzzo A.,University of Bristol | And 10 more authors.
Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010 | Year: 2010

Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate highfidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm. © 2009 Optical Society of America.


Overney F.,Federal Office of Metrology | Jeanneret B.,Federal Office of Metrology
IEEE Transactions on Instrumentation and Measurement | Year: 2011

An RLC bridge based on an automated synchronous sampling system has been developed using commercially available high-resolution analog-to-digital and digital-to-analog converters. This bridge allows the comparison of any kind of impedance standards in the four-terminal-pair configuration at frequencies between 50 Hz and 20 kHz within a range from 1 Ω to 100 kΩ. An automatic balance of the bridge is carried out using a downhill simplex algorithm. Consistency checks have been realized by comparing resistance, inductance, and capacitance standards at different frequencies. The consistency of the measured voltage ratio is better than 20 μV/V over the whole frequency range and even smaller than 5 μV/V around 1 kHz. Finally, the results of the calibration of a 10-nF capacitance standard have been compared to those obtained using a commercial high-accuracy capacitance bridge. The difference is smaller than the commercial bridge specifications over the whole frequency range. © 2006 IEEE.


He G.,EXFO Inc. | Breton M.,EXFO Inc. | Dallaire-Poirier S.,EXFO Inc. | Bull G.,EXFO Inc. | And 4 more authors.
IET Optoelectronics | Year: 2011

The authors propose an improved near-field scanning system for measuring the mode distribution exiting a multimode fibre (MMF), notably for evaluating conformity to the encircled flux (EF) standard of a measurement source used for MMF loss/attenuation characterisation. This system offers advantages over both charge coupled device (CCD)-based and traditional scanning approaches. EF measurements taken with this new system are in excellent agreement with CCD-based measurements. © 2011 The Institution of Engineering and Technology.


Welti A.,ETH Zurich | Kanji Z.A.,ETH Zurich | Luond F.,Federal Office of Metrology | Stetzer O.,ETH Zurich | Lohmann U.,ETH Zurich
Journal of the Atmospheric Sciences | Year: 2014

To identify the temperature and humidity conditions at which different ice nucleation mechanisms are active, the authors conducted experiments on 200-, 400-, and 800-nm size-selected kaolinite particles, exposing them to temperatures between 218 and 258Kand relative humidities with respect to ice (RHi) between 100% and 180%, including the typical conditions for cirrus and mixed-phase-cloud formation. Measurements of the ice active particle fraction as a function of temperature and relative humidity with respect to ice are eported. The authors find enhanced activated fractions when water saturation is reached at mixed-phasecloud temperatures between 235 and 241K and a distinct increase in the activated fraction below 235K at conditions below water saturation. To provide a functional description of the observed ice nucleation mechanisms, the experimental results are analyzed by two different particle-surface models within the framework of classical nucleation theory. Describing the ice nucleation activity of kaolinite particles by assuming deposition nucleation to be the governing mechanism below water saturation was found to be inadequate to represent the experimental data in the whole temperature range investigated. The observed increase in the activated fraction below water saturation and temperatures below 235K corroborate the assumption that an appreciable amount of adsorbed or capillary condensed water is present on kaolinite particles, which favors ice nucleation. © 2014 American Meteorological Society.


Di Domenico G.,University Of Neuchtel | Devenoges L.,University Of Neuchtel | Joyet A.,University Of Neuchtel | Stefanov A.,Federal Office of Metrology | Thomann P.,University Of Neuchtel
Proceedings of the IEEE International Frequency Control Symposium and Exposition | Year: 2011

The continuous atomic fountain primary frequency standard FOCS-2 is quite unique since all the atomic fountain clocks presently contributing to the international atomic time (TAI) are operating in pulsed mode [1]. Our alternative approach offers the possibility to operate with a high atomic flux without the collisional shift limiting the accuracy or the Dick effect limiting the stability when a quartz is used as local oscillator [2], [3]. Moreover, it contributes to the metrological diversity since the relative importance of the error budget contributors is different in the two types of fountains, notably for microwave cavity and density related effects. In this contribution we present the status of the metrological evaluation of the continuous fountain FOCS-2. Thanks to an innovative atomic beam source followed by an atomic state preparation stage, we reach a signal-to-noise ratio of 600√Hz and thus a relative frequency instability of 6 × 10-14 T-1/2. A detailed investigation of the frequency shifts which are specific to the continuous operation (light-shift from the source and cavity end-to-end phase shift) shows that the continuous fountain is compatible with an inaccuracy at the 10-15 level or below. © 2011 IEEE.


Rietveld G.,Dutch National Metrology Institute | Braun J.-P.,Federal Office of Metrology | Martin R.,Laborarorio Central Official de Electrotecnia | Wright P.,National Physical Laboratory United Kingdom | And 4 more authors.
IEEE Transactions on Instrumentation and Measurement | Year: 2015

Grid operators are facing a significant challenge in ensuring continuity and quality of electricity supply, while more and more renewable energy sources are connected to the grid. The resulting evolvement of so-called smart grids strongly relies on the availability of reliable measurement data for monitoring and control of these grids. This paper presents an overview of the results achieved in recent smart grid metrology research in Europe, aiming to realize the required metrology infrastructure for ensuring security and quality of supply in future smart electrical grids. A consortium of 22 metrology and research institutes has made significant steps in modeling of smart grids, enhancement of the revenue metering infrastructure, performance and evaluation of onsite power quality campaigns, and the development of a metrological framework for traceability of smart grid phasor measurements. © 1963-2012 IEEE.


Bielsa F.,French National Laboratory of Metrology and Testing | Eichenberger A.,Federal Office of Metrology | Gilbert O.,French National Laboratory of Metrology and Testing | Juncar P.,Institute National Of Metrologie Lne Inm Cnam | Geneves G.,French National Laboratory of Metrology and Testing
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010

In watt balance experiments, the determination of the position and the velocity of a moving coil have a crucial contribution in the overall uncertainty. In this paper, we present optical devices that will be set up to measure the two above mentioned parameters © 2010 IEEE.


Gilbert O.,French National Laboratory of Metrology and Testing | Bielsa F.,French National Laboratory of Metrology and Testing | Juncar P.,Institute National Of Metrologie Lne Inm Cnam | Eichenberger A.,Federal Office of Metrology | Geneves G.,French National Laboratory of Metrology and Testing
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010

The alignment of optical devices such as interferometers and laser position detectors is needed for the different adjustments of watt balances. This paper describes the optical apparatus and the numerical simulations developed to tune the alignment of experimental setup. A telescope coupled with a CCD camera and data processing are presented in detail. © 2010 IEEE.


Voros S.,Federal Office of Metrology | Anton M.,Physikalisch - Technische Bundesanstalt | Boillat B.,Federal Office of Metrology
Physics in Medicine and Biology | Year: 2012

A significant proportion of cancer patients is treated using MeV electron radiation. One of the measurement methods which is likely to furnish reliable dose values also under non-reference conditions is the dosimetry using alanine and read-out via electron spin resonance (ESR). The system has already proven to be suitable for QA purposes for modern radiotherapy involving megavoltage x-rays. In order to render the secondary standard measurement system of the PhysikalischTechnische Bundesanstalt based on alanine/ESR useable for dosimetry in radiotherapy, the dose-to-water (D W) response of the dosemeter needs to be known for relevant radiation qualities. For MeV electrons, the D W response was determined using the Fricke primary standard of the Swiss Federal Office of Metrology. Since there were no citable detailed publications on the Swiss primary standard available, this measurement system is described in some detail. The experimental results for the D W response are compared to results of Monte Carlo simulations which model in detail the beams furnished by the electron accelerator as well as the geometry of the detectors. The agreement between experiment and simulation is very good, as well as the agreement with results published by the National Research Council of Canada which are based on a different primary standard. No significant dependence of the D W response was found in the range between 6 and 20MeV. It is therefore suggested to use a unique correction factor k E for alanine for all MeV qualities of k E = 1.012 0.010. © 2012 Institute of Physics and Engineering in Medicine.

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