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Reference : UMR7538-ANNAMY0-005
Workplace : VILLETANEUSE
Date of publication : Monday, May 18, 2020
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 October 2020
Proportion of work : Full time
Remuneration : From 2728 € gross monthly according to experience
Desired level of education : PhD
Experience required : 1 to 4 years
The post-doctoral researcher will contribute to the development, optimization and exploitation of optical fiber links between France and UK, Germany and Italy. This work is part of an European project aiming at the very precise comparison of distant optical clocks, in order to investigate their consistency and, more generally, to perform advanced tests of physics, including for instance search for dark matter.
The post-doctoral researcher will join the group Metrology, Molecules and Fundamental tests of Laser Physics Department.
He/she will share his activities between the test and optimization of a new optical fiber link to Italy and the optimization and exploitation of two existing links to UK and Germany.
He/she will test different configurations for the better performance of the link to the Italian border at Modane, analyse the free-running noise as well as the residual noise after compensation, and optimize the link. He/she will have to process the data, with special attention to cycle slips and gaps.
The postdoctoral researcher will also contribute to the exploitation of the French part of the two international links to UK and Germany and to the frequency comparisons performed at LPL and at Strasbourg. He/she will perform various upgrades, process the data both of the link residual phase noise and the frequency comparisons, and assess the stability and uncertainty of the frequency transfer.
The candidates should have a PhD related to optics, laser-matter interaction, or optoelectronics with excellent experimental skills. Knowledge in noise analysis and time-frequency fundamental metrology is obviously a strong asset. Experience in laser frequency stabilization, low-noise electronics or signal processing is beneficial.
Optical fiber links were developed in the last decade to transfer an ultrastable frequency reference over hundreds of km, with a minimal degradation of its stability and accuracy performance. They consist of transmitting an ultrastable laser, which frequency is controlled with atomic clocks, through an optical fiber to the remote lab. The propagation phase noise is detected through an interferometric set-up and is actively corrected. We demonstrated that the transferred signal frequency is copying the input signal frequency with residual fractional instabilities below 10-15 at 1-s averaging time. The long-term stability can reach the 10-20 range and the residual frequency offset is also in the 10-20 range.
This activity takes place at the Laboratoire de Physique des Lasers (UMR 7538 CNRS-Université Sorbonne Paris Nord, formerly Université Paris 13), in Villetaneuse, within the MMTF (Métrologie, Molécules et Tests Fondamentaux) group (http://www-lpl.univ-paris13.fr/UK/Equipe-MMT-presentation.awp). The work will be performed in close collaboration with SYRTE, the French national metrological institute for time/frequency, in Paris.
LPL (Université Paris 13, CNRS) and LNE-SYRTE (Observatoire de Paris, CNRS, UPMC) have pioneered the development of optical links for applications both in time and frequency metrology and in high-precision measurements. We are developing a national metrological network to transfer an ultrastable frequency signal to 20 labs over France in the framework of the REFIMEVE+ project. .This network is connected to to PTB in Germany, NPL in UK and very recently INRIM in Italy in order to compare the best optical clocks of these countries with the clocks developed at SYRTE.
The postdoctoral researcher will be involved in our international collaboration networks in the frame of the Euramet project ROCIT (https://www.euramet.org/research-innovation/search-research-projects/details/project/robust-optical-clocks-for-international-timescales/).
During the period of link optimisation, or in case of failure, he/she will have also to go to the field in order to perform local loss and spectrum measurements.
Euramet project ROCIT (https://www.euramet.org/research-innovation/search-research-projects/details/project/robust-optical-clocks-for-international-timescales/)
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