Tackling the Limits of Optical Fiber Links

Fabio Stefani (1, 2) , Olivier Lopez (1) , Anthony Bercy (1, 2) , Won-Kyu Lee (2) , Christian Chardonnet (1) , Giorgio Santarelli (2) , Paul-Eric Pottie (2) , Anne Amy-Klein (1)

1 MMTF
2 LNE - SYRTE - Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace

We theoretically and experimentally investigate relevant noise processes arising in optical fiber links, which fundamentally limit their relative stability. We derive the unsuppressed delay noise for three configurations of optical links: two-way method, Sagnac interferometry, and actively compensated link, respectively designed for frequency comparison, rotation sensing, and frequency transfer. We also consider an alternative two-way setup allowing real-time frequency comparison and demonstrate its effectiveness on a proof-of-principle experiment with a 25-km fiber spool. For these three configurations, we analyze the noise arising from uncommon fiber paths in the interferometric ensemble and design optimized interferometers. We demonstrate interferometers with very low temperature sensitivity of respectively -2.2, -0.03 and 1 fs/K. We use one of these optimized interferometers on a long haul compensated fiber link of 540 km. We obtain a relative frequency stability of 3x10^-20 after 10,000 s of integration time.

Mots clés: Interferometers; Physics - Optics; Time and Frequency Metrology; Optical Links; Frequency Stabiliezd Lasers; Fiber Optics

Domaines: Physique Quantique [quant-ph]; Physique [physics]

Fabio Stefani, Olivier Lopez, Anthony Bercy, Won-Kyu Lee, Christian Chardonnet, et al.. Tackling the Limits of Optical Fiber Links. Journal of the Optical Society of America B, 2015, 32 (5), pp.787. ⟨10.1364/JOSAB.32.000787⟩. ⟨hal-01090057⟩