Single-end-access distributed strain sensing with wide dynamic range using higher-speed Brillouin optical correlation-domain reflectometry

Abstract

Single-end-access real-time fiber-optic distributed strain sensing has recently been demonstrated using an ultrahigh-speed configuration of Brillouin optical correlation-domain reflectometry (BOCDR). Its extremely high sampling rate was, however, achieved at the cost of a limited strain dynamic range (<0.2%). Here, by employing a noise-floor compensation technique, we develop a new cost-effective higher-speed configuration of BOCDR with a wide strain dynamic range (up to 2.0%; evaluated by static strain measurement). This value is larger than that of any other BOCDR configuration. Using this configuration, we demonstrate some fundamental distributed strain measurements and breakage detection.

Recent Advances in Brillouin Optical Correlation-Domain Reflectometry

“…An apodization scheme based on synchronous intensity modulation [53] and a lock-in detection scheme [54] were also performed to suppress the noise floor and to enhance the strain dynamic range, etc. Finally, to achieve high-speed operation (the sampling rate was limited to <20 Hz in the standard configuration [55]), phase-detected BOCDR [56][57][58] and slope-assisted BOCDR were developed. In both schemes, the idea for high-speed operation is the same; namely, the omission of the frequency-scanning process for acquiring the BGS.…”

Long Range Raman-Amplified Distributed Acoustic Sensor Based on Spontaneous Brillouin Scattering for Large Strain Sensing

“…Single-SA BOCDA systems have been used to measure vibrations of up to 100 Hz over 130 m of sensing fiber with a spatial resolution of 3.45 cm [33]. Dual-SA BOCDA is a modified version of single-SA BOCDA interrogation technique capable of measuring dynamic strain with frequencies and amplitude of 625 Hz and 700 µε, respectively, over 20 m sensing fiber and with 7 cm spatial resolution [34]. Brillouin Optical Correlation-domain Refractometry (BOCDR) is another correlation-domain interrogation technique but unlike BOCDA, it only requires access to a single-end of the sensing fiber [34,35].…”

“…Dual-SA BOCDA is a modified version of single-SA BOCDA interrogation technique capable of measuring dynamic strain with frequencies and amplitude of 625 Hz and 700 µε, respectively, over 20 m sensing fiber and with 7 cm spatial resolution [34]. Brillouin Optical Correlation-domain Refractometry (BOCDR) is another correlation-domain interrogation technique but unlike BOCDA, it only requires access to a single-end of the sensing fiber [34,35]. Sensing systems based on BOCDR have been used to measure dynamic events with a strain range and frequency of 3 mε and 100 Hz, respectively, and a spatial resolution of 40 cm over a 12 m-long fiber [34].…”

“…Brillouin Optical Correlation-domain Refractometry (BOCDR) is another correlation-domain interrogation technique but unlike BOCDA, it only requires access to a single-end of the sensing fiber [34,35]. Sensing systems based on BOCDR have been used to measure dynamic events with a strain range and frequency of 3 mε and 100 Hz, respectively, and a spatial resolution of 40 cm over a 12 m-long fiber [34]. Despite their excellent spatial resolutions, systems based on correlation-domain interrogation techniques are best suited for applications that require high spatial resolution dynamic measurement over a relatively short sensing range.…”

Bending-loss-independent operation of slope-assisted Brillouin optical correlation-domain reflectometry

“…Since the basic idea was first implemented 22 , BOCDR has been extensively studied for more than ten years, leading to substantial improvement of its performance 24 – 30 . Some of the recent advances include the development of simplified configurations 25 , polymer-fiber-based configurations 27 , and high-speed configurations, such as phase-detected BOCDR 28 , 29 and slope-assisted (SA-) BOCDR 30 . In SA-BOCDR, the Brillouin frequency shift (BFS), which corresponds to the information on the applied strain and temperature, is converted into the spectral power on the slope of the Brillouin gain spectrum (BGS).…”