Coding-nhanced Ultrafast and Distributed Brillouin Dynamic Gratings Sensing Using Coherent Detection

Arik Bergman, Tomi Langer, Moshe Tur

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Probe coding can significantly improve the signal to noise ratio and measurement speed in Brillouin Dynamic Grating (BDG) fiber-optic distributed sensing, but only if coherent reception is employed. This is because both the amplitude and phase of the BDG impulse response vary along the fiber due to fiber nonuniformities, as well as the effect of the distributed measurand. As a result, the backreflections from individual code chips add coherently and, therefore, the total backscattered return cannot be decoded by a direct detection receiver (excluding some rare scenarios). Here, following a theoretical derivation of the BDG impulse response, a fully coherent BDG-based sensor is reported. Using a 64-chip Golay bipolar (phase) code, an eightfold sensitivity improvement (over single pulse interrogation) is demonstrated. With a code repetition rate of 1 MHz, basically determined by the length of the fiber, 750-Hz strain oscillations were measured with no averaging, with a spatial resolution of 20 cm.

Original languageEnglish
Article number7726056
Pages (from-to)5593-5600
Number of pages8
JournalJournal of Lightwave Technology
Issue number24
StatePublished - 15 Dec 2016
Externally publishedYes


  • Coherent optical effects
  • dynamic gratings
  • fiber Bragg gratings
  • fiber optics sensors
  • optical time domain reflectometry
  • pulse compression


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