Fast sinusoidal frequency scan OFDR for long distance distributed acoustic sensing

Lihi Shiloh, Avishay Eyal

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Implementation of Optical Frequency Domain Reflectometry (OFDR) requires a source whose instantaneous frequency can be accurately scanned over a sufficiently wide frequency range. Achieving high repetition rates of accurate linear frequency sweeps can be rather challenging. In contrast, fast and accurate Sinusoidal Frequency Scan (SFS-OFDR) can be easily implemented via direct or external optical frequency modulation. While enabling high spatial resolution measurements of a sensing fiber at high scan rates, SFS-OFDR requires a special processing algorithm to convert the detector output to fiber profiles. Previous implementation of the algorithm involved O(N2) complexity and prohibited real time operation. In this work a novel algorithm for processing SFS-OFDR raw data is introduced. Based on two consecutive FFT operations, the algorithm produces the fiber profile with O(NlogN) operations and lends itself for real time applications. The new method was tested via simulation and experiment. It enabled static detection with high resolution (∼3m) at 64km and highly sensitive dynamic detection (stretching amplitude of 70nm) near the end of a 64km sensing fiber with spatial resolution <10m and with 400Hz scan repetition rate.

Original languageEnglish
Title of host publication25th International Conference on Optical Fiber Sensors
EditorsLibo Yuan, Youngjoo Chung, Wei Jin, Byoungho Lee, John Canning, Kentaro Nakamura
ISBN (Electronic)9781510610910
StatePublished - 2017
Event25th International Conference on Optical Fiber Sensors, OFS 2017 - Jeju, Korea, Republic of
Duration: 24 Apr 201728 Apr 2017

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering


Conference25th International Conference on Optical Fiber Sensors, OFS 2017
Country/TerritoryKorea, Republic of


  • Distributed Acoustic Sensing (DAS)
  • OFDR
  • Optical Fiber Sensors (OFS)

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Fast sinusoidal frequency scan OFDR for long distance distributed acoustic sensing'. Together they form a unique fingerprint.

Cite this