Impact Statement:A broadband UWFBG array with flat reflection spectrum is proposed for distributed vibration sensing. The sensing signal of the UWFBG array is 17dB higher than the RBS, wh...Show More
Abstract:
An enhanced distributed optical fiber sensor based on broadband ultra-weak fiber Bragg grating array (UWFBG) for dynamic strain measurement with large temperature toleran...Show MoreMetadata
Impact Statement:
A broadband UWFBG array with flat reflection spectrum is proposed for distributed vibration sensing. The sensing signal of the UWFBG array is 17dB higher than the RBS, which can greatly improve the sensing distance and sensitivity. Compared with normal UWFBG, the reflection spectrum of the broadband UWFBG is very flat, could support large temperature differences. Multiple vibration events can be accurately restored. It is a very promising technology in downhole vertical seismic detection.
Abstract:
An enhanced distributed optical fiber sensor based on broadband ultra-weak fiber Bragg grating array (UWFBG) for dynamic strain measurement with large temperature tolerance range was proposed and experimentally demonstrated. The reflectivity of UWFBG is about -50 dB, and the intensity of the reflected signal is 17 dB higher than the Rayleigh back-scattering. Using an unbalanced Michelson interferometer (MI) and 3 × 3 coupler phase demodulation technique, multiple vibration events can be detected simultaneously. We experimentally demonstrated the effectiveness of the technique by monitoring dynamic strain with a large temperature range of 20-200 °C. The minimum phase detection of the system is 1.02 × 10 - 3 rad/√Hz, and the signal-to-noise ratio (SNR) is above 59.2 dB @100 Hz at different temperatures. Meanwhile, the system has a wide frequency response from 10 Hz to 4.5 kHz.
Published in: IEEE Photonics Journal ( Volume: 12, Issue: 4, August 2020)
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