scholarly journals Fast Measurement of Brillouin Frequency Shift in Optical Fiber Based on a Novel Feedforward Neural Network

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 474
Author(s):  
Fen Xiao ◽  
Mingxing Lv ◽  
Xinwan Li
Keyword(s):  
Neural Network ◽  
Optical Fiber ◽  
Frequency Shift ◽  
Brillouin Scattering ◽  
Principal Component ◽  
Feedforward Neural Network ◽  
Gain Spectrum ◽  
Fiber Sensors ◽  
Brillouin Gain ◽  
Distributed Optical Fiber

Brillouin scattering-based distributed optical fiber sensors have been successfully employed in various applications in recent decades, because of benefits such as small size, light weight, electromagnetic immunity, and continuous monitoring of temperature and strain. However, the data processing requirements for the Brillouin Gain Spectrum (BGS) restrict further improvement of monitoring performance and limit the application of real-time measurements. Studies using Feedforward Neural Network (FNN) to measure Brillouin Frequency Shift (BFS) have been performed in recent years to validate the possibility of improving measurement performance. In this work, a novel FNN that is 3 times faster than previous FNNs is proposed to improve BFS measurement performance. More specifically, after the original Brillouin Gain Spectrum (BGS) is preprocessed by Principal Component Analysis (PCA), the data are fed into the Feedforward Neural Network (FNN) to predict BFS.

scholarly journals Measurement Improvement of Distributed Optical Fiber Sensor via Lorenz Local Single Peak Fitting Algorithm

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1166
Author(s):  
Bin Liu ◽  
Jianping He ◽  
Shihai Zhang ◽  
Yinping Zhang ◽  
Jianan Yu ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Frequency Shift ◽  
Optical Fiber Sensor ◽  
Gain Spectrum ◽  
Fiber Sensor ◽  
Peak Fitting ◽  
Fitting Algorithm ◽  
Distributed Optical Fiber Sensor ◽  
Brillouin Gain ◽  
Distributed Optical Fiber

Brillouin frequency shift (BFS) of distributed optical fiber sensor is extracted from the Brillouin gain spectrum (BGS), which is often characterized by Lorenz type. However, in the case of complex stress and optical fiber self damage, the BGS will deviate from Lorenz type and be asymmetric, which leads to the extraction error of BFS. In order to enhance the extraction accuracy of BFS, the Lorenz local single peak fitting algorithm was developed to fit the Brillouin gain spectrum curve, which can make the BSG symmetrical with respect to the Brillouin center frequency shift. One temperature test of a fiber-reinforced polymer (FRP) packaged sensor whose BSG curve is asymmetric was conducted to verify the idea. The results show that the local region curve of BSG processed by the developed algorithm has good symmetry, and the temperature measurement accuracy obtained by the developed algorithm is higher than that directly measured by demodulation equipment. Comparison with the reference temperature, the relative measurement error measured by the developed algorithm and BOTDA are within 4% and 8%, respectively.

scholarly journals Distributed Dynamic Strain Sensing Based on Brillouin Scattering in Optical Fibers

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5629
Author(s):  
Agnese Coscetta ◽  
Aldo Minardo ◽  
Luigi Zeni
Keyword(s):  
Optical Fiber ◽  
Brillouin Scattering ◽  
Traffic Monitoring ◽  
Optical Fiber Sensors ◽  
Dynamic Strain ◽  
Dynamic Measurements ◽  
Research Activity ◽  
Fiber Sensors ◽  
Railway Traffic ◽  
Distributed Optical Fiber

Over the past three decades, extensive research activity on Brillouin scattering-based distributed optical fiber sensors has led to the availability of commercial instruments capable of measuring the static temperature/strain distribution over kilometer distances and with high spatial resolution, with applications typically covering structural and environmental monitoring. At the same time, the interest in dynamic measurements has rapidly grown due to the relevant number of applications which could benefit from this technology, including structural analysis for defect identification, vibration detection, railway traffic monitoring, shock events detection, and so on. In this paper, we present an overview of the recent advances in Brillouin-based distributed optical fiber sensors for dynamic sensing. The aspects of the Brillouin scattering process relevant in distributed dynamic measurements are analyzed, and the different techniques are compared in terms of performance and hardware complexity.

scholarly journals Distributed Optical Fiber Sensor Applications in Geotechnical Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7514
Author(s):  
Aldo Minardo ◽  
Luigi Zeni ◽  
Agnese Coscetta ◽  
Ester Catalano ◽  
Giovanni Zeni ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Brillouin Scattering ◽  
Optical Fiber Sensor ◽  
Early Warning Systems ◽  
Optical Fiber Sensors ◽  
Small Scale ◽  
Sudden Increase ◽  
Fiber Sensors ◽  
Artificial Rainfall ◽  
Distributed Optical Fiber

We report the experimental application of distributed optical fiber sensors, based on stimulated Brillouin scattering (SBS), to the monitoring of a small-scale granular slope reconstituted in an instrumented flume and subjected to artificial rainfall until failure, and to the monitoring of a volcanic rock slope. The experiments demonstrate the sensors’ ability to reveal the sudden increase in soil strain that foreruns the failure in a debris flow phenomenon, as well as to monitor the fractures in the tuff rocks. This study offers an important perspective on the use of distributed optical fiber sensors in the setting up of early warning systems for landslides in both rock and unconsolidated materials.

scholarly journals Long-Term Monitoring of a Tunnel in a Landslide Prone Area by Brillouin-Based Distributed Optical Fiber Sensors

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7032
Author(s):  
Aldo Minardo ◽  
Ester Catalano ◽  
Agnese Coscetta ◽  
Giovanni Zeni ◽  
Caterina Di Maio ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Brillouin Scattering ◽  
Strain Sensor ◽  
Fiber Sensors ◽  
Prone Area ◽  
Fiber Deformation ◽  
Active Landslide ◽  
Italian Apennines ◽  
Distributed Optical Fiber ◽  
Stimulated Brillouin

This paper shows the results of the monitoring of the deformations of a tunnel, carried out using a distributed optical fiber strain sensor based on stimulated Brillouin scattering. The artificial tunnel of the national railway crosses the accumulation zone of an active landslide, the Varco d’Izzo earthflow, in the southern Italian Apennines. Severely damaged by the landslide movements, the tunnel was demolished and rebuilt in 1992 as a reinforced concrete box flanked by two deep sheet pile walls. In order to detect the onset of potentially dangerous strains of the tunnel structure and follow their time trend, the internal deformations of the tunnel are also monitored by a distributed fiber-optic strain sensor since 2016. The results of the monitoring activity show that the deformation profiles are characterized by strain peaks in correspondence of the structural joints. Furthermore, the elongation of the fiber strands crossing the joints is consistent with the data derived by other measurement systems. Experiments revealed an increase in the time rate of the fiber deformation in the first and last part of the monitoring period when the inclinometers of the area also recorded an acceleration in the landslide movements.

Sign in / Sign up

Export Citation Format

Share Document