Distributed and dynamic strain sensing with high spatial resolution and large measurable strain range

A distributed and dynamic strain sensing system based on frequency-scanning phase-sensitive optical time domain reflectometry is proposed and demonstrated. By utilizing an RF pulse scheme with a fast arbitrary waveform generator, a train of optical pulses covering a large range of different optical frequencies, short pulse width, and high extinction ratio is generated. Also, a Rayleigh-enhanced fiber is used to eliminate the need for averaging, allowing single-shot operation. Using direct detection and harnessing a dedicated least mean square algorithm, the method exhibits a record high spatial resolution of 20 cm, concurrently with a large measurable strain range (80µε, 60 demonstrated), a fast sampling rate of 27.8 kHz (almost the maximum possible for a 55 m long fiber and 60 frequency steps), and low strain noise floor (<1.8nε/√Hz for vibrations below 700 Hz and <0.7nε/√Hz for higher frequencies).


Published in:
Optics Letters, 45, 18, 5020-5023
Year:
Sep 04 2020
Laboratories:


Note: The status of this file is: Anyone


 Record created 2020-09-07, last modified 2020-10-29

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