Name: Sebastien Fernandez - Free space optical link to a tethered balloon for frequency transfer and chronometric Geodesy
Start: 2023-11-16T11:00:00+01:00
End: 2023-11-16T12:30:00+01:00
Location: Paris

Sebastien Fernandez - Free space optical link to a tethered balloon for frequency transfer and chronometric Geodesy

jeudi 16 novembre 2023 - 11:00

lundi 13 novembre 2023
mardi 14 novembre 2023
mercredi 15 novembre 2023
jeudi 16 novembre 2023
11:00 Free space optical link to a tethered balloon for frequency transfer and chronometric Geodesy - Sebastien Fernandez (SYRTE)
Free space optical link to a tethered balloon for frequency transfer and chronometric Geodesy
- Sebastien Fernandez (SYRTE)
11:00 - 12:30
Room: Salle Denisse (ex Atelier) Optical clocks have demonstrated uncertainties in the $10^{-18}$ region in fractional frequency. This makes them prime candidates for applications like chronometric geodesy, navigation and fundamental physics. Such applications require frequency transfer between a reference clock in a static place and a transportable one, e.g. enabling geopotential mapping over a region. It is thus necessary to develop a free-space optical link, in order to extend the current fiber link network in a flexible way. I will present the TOFU (“Transfert Optique de Fréquence Ultrastable”) project. It consists in developing a free space phase-stabilized optical link through an airborne relay, over expected distances up to ~100km. We already set up a 300m-folded link between a ground transceiver and a retroreflector carried by a balloon at CNES premises. I will present the design of this system, which includes a phase measurement and compensation unit and an optical transceiver. Following, I will show the performance and limitations of the system, that we evaluated during a measurement campaign lead in March 2023. Finally, I will describe the further technical developments in order to build an active airborne transceiver, replacing the passive retroreflector.