Publications (14)
The stability of an optical clock laser transferred to the interrogation oscillator for a Cs fountain
B. Lipphardt, G. Grosche, U. Sterr +3
We stabilise a microwave oscillator at 9.6 GHz to an optical clock laser at 344 THz by using a fibre-based femtosecond laser frequency comb as a transfer oscillator. With a second…
Chirped Frequency Transfer with an accuracy of and its Application to the Remote Synchronisation of Timescales
S. M. F. Raupach, G. Grosche
We demonstrate combined high-fidelity long-haul transfer of a linearly chirped, optical frequency and time transfer. In a proof-of-principle experiment we transfer an optical frequ…
Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks
B. M. Roberts, P. Delva, A. Al-Masoudi +51
We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in…
Measurement noise floor for a long-distance optical carrier transmission via fiber
G. Grosche, O. Terra, K. Predehl +6
We investigated the measurement floor and link stability for the transfer of an ultra-stable optical frequency via an optical fiber link. We achieved a near-delay-limited instabili…
Interrogation laser for a strontium lattice clock
T. Legero, Ch. Lisdat, J. S. R. Vellore Winfred +4
We report on the setup and characterization of a 698 nm master-slave diode laser system to probe the 1S0-3P0 clock transition of strontium atoms confined in a one-dimensional optic…
Long-distance chronometric leveling with a portable optical clock
J. Grotti, I. Nosske, S. B. Koller +19
We have measured the geopotential difference between two locations separated by by comparison of two optical lattice clocks via an interferometric fiber link, uti…
Test of special relativity using a fiber network of optical clocks
P. Delva, J. Lodewyck, S. Bilicki +28
Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching…
Optical frequency transfer via a 660 km underground fiber link using a remote Brillouin amplifier
S. M. F. Raupach, A. Koczwara, G. Grosche
In long-haul optical continuous-wave frequency transfer via fiber, remote bidirectional Er-doped fiber amplifiers are commonly used to mitigate signal attenuation. We demonstra…
A clock network for geodesy and fundamental science
C. Lisdat, G. Grosche, N. Quintin +32
Leveraging the unrivaled performance of optical clocks in applications in fundamental physics beyond the standard model, in geo-sciences, and in astronomy requires comparing the fr…
Brillouin amplification in phase coherent transfer of optical frequencies over 480 km fiber
O. Terra, G. Grosche, H. Schnatz
We describe the use of fiber Brillouin amplification (FBA) for the coherent transmission of optical frequencies over a 480 km long optical fiber link. FBA uses the transmission fib…
First international comparison of fountain primary frequency standards via a long distance optical fiber link
J. Guéna, S. Weyers, M. Abgrall +25
We report on the first comparison of distant caesium fountain primary frequency standards (PFSs) via an optical fiber link. The 1415 km long optical link connects two PFSs at LNE-S…
Optical frequency transfer via 146 km fiber link with 10^{-19} relative accuracy
G. Grosche, O. Terra, K. Predehl +5
We demonstrate the long-distance transmission of an ultra-stable optical frequency derived directly from a state-of-the-art optical frequency standard. Using an active stabilizatio…
Remote frequency measurement of the 1S0-3P1 transition in laser cooled Mg-24
J. Friebe, M. Riedmann, T. Wübbena +9
We perform Ramsey-Bordé spectroscopy on laser-cooled magnesium atoms in free fall to measure the 1S0 \rightarrow 3P1 intercombination transition frequency. The measured value of 6…
The 87-Sr optical frequency standard at PTB
St. Falke, H. Schnatz, J. S. R. Vellore Winfred +8
With 87-Sr atoms confined in a one dimensional optical lattice, the frequency of the optical clock transition 5s^2 ^1S_0 - 5s5p ^3P_0 has been determined to be 429 228 004 229 872.…