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Scientific article
English

Phase-noise measurements in long-fiber interferometers for quantum-repeater applications

Publication date2008
Abstract

Many protocols for long distance quantum communication require interferometric phase stability over long distances of optical fibers. In this paper we investigate the phase noise in long optical fibers both in laboratory environment and in installed commercial fibers in an urban environment over short time scales (up to hundreds of µs). We show that the phase fluctuations during the travel time of optical pulses in long-fiber loops are small enough to obtain high visibility first-order interference fringes in a Sagnac interferometer configuration for fiber lengths up to 75 km. We also measure phase fluctuations in a Mach-Zehnder interferometer in installed fibers with arm length 36.5 km. We verify that the phase noise respects Gaussian distribution and measure the mean phase change as a function of time difference. The typical time needed for a mean phase change of 0.1 rad is of order of 100 µs, which provides information about the time scale available for active phase stabilization. Our results are relevant for future implementations of quantum repeaters in installed optical fiber networks.

Keywords
  • Electric noise measurement
  • Gaussian distribution
  • Mach-Zehnder interferometers
  • Optical fibre networks
  • Optical repeaters
  • Phase noise
  • Quantum communication
  • Sagnac interferometers
Citation (ISO format)
MINAR, Jiri et al. Phase-noise measurements in long-fiber interferometers for quantum-repeater applications. In: Physical review, A, Atomic, molecular, and optical physics, 2008, vol. 77, n° 5, p. 052325. doi: 10.1103/PhysRevA.77.052325
Identifiers
ISSN of the journal1050-2947
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