Fiber Bragg grating sensors for aerospace applications: a review

Civil engineering assets and geo-structures continually deteriorate during their lifetime, particularly in harsh environments that may be contaminated with corrosive substances. However, efficient and constant structural health monitoring and accurate prediction of the service-life of these assets can help to ensure their safety, performance, and health conditions and enable proper maintenance and rehabilitation. Nowadays, many of the largest cities throughout the world are situated in coastal zones, leading to a dramatic increase in the construction of nearshore geo-structures/infrastructures which are vulnerable to corrosion attacks resulting from salinity contamination. Additionally, seawater intrusion can threaten the quality and the sustainability of fresh groundwater resources, which are a crucial resource in coastal areas. To address these issues, detection of salinity in soil utilizing a novel polymer optical fibre Bragg grating (POFBG) sensor was investigated in this research. Experiments were carried out at different soil water contents with different salinities to assess the sensor’s response in a representative soil environment. The sensitivity of the POFBG sensor to salinity concentrations in water and soil environment is estimated as 58 ± 2 pm/%. The average standard error value in salinity is calculated as 0.43% for the samples with different soil water contents. The results demonstrate that the sensor is a promising and practical tool for the measurement and monitoring with high precision of salinity contamination in soil.

Section: Sensor Principle and Fabricationmentioning

confidence: 99%

Nearshore Contamination Monitoring in Sandy Soils Using Polymer Optical Fibre Bragg Grating Sensing Systems

Fadaie

Mehravar

Webb

et al. 2022

“…Gratings are periodic structures fabricated on the fiber core, enabling the interaction of light with the surrounding environment. In recent years, fiber optic grating technology has evolved to include several grating types, including fiber Bragg grating (FBG) [ 7 , 8 , 9 ], long-period fiber grating (LPFG) [ 10 ] and tilted fiber grating (TFG) [ 11 , 12 ]. Compared with the above-mentioned optical fiber grating, the excessively tilted fiber grating (Ex-TFG) shows a series of orthogonal polarization dual peaks in the transmission spectrum and exhibits a high surrounding refractive index (SRI) sensitivity with low temperature crosstalk.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Laser Inscribed Excessively Tilted Fiber Grating for Humidity Sensing

Jing,

Liu,

Liu

et al. 2024

We propose a humidity sensor using an excessively tilted fiber grating (Ex-TFG) coated with agarose fabricated using femtosecond laser processing. The processed grating showcases remarkable differentiation between TE and TM modes, achieving an exceptionally narrow bandwidth of approximately 1.5 nm and an impressive modulation depth of up to 15 dB for both modes. We exposed the agarose-coated TFG sensor to various relative humidity levels and monitored the resonance wavelength to test its humidity sensing capability. Our findings demonstrated that the sensor exhibited a rapid response time (2–4 s) and showed a high response sensitivity (18.5 pm/%RH) between the humidity changes and the resonant wavelength shifts. The high sensitivity, linearity, repeatability, low hysteresis, and excellent long-term stability of the TFG humidity sensor, as demonstrated in our experimental results, make it an attractive option for environmental monitoring or biomedical diagnosis.

“…On the other hand, and due to their materials and fabrication, fiber optic sensors share advantages such as compact size, light weight, immunity to electromagnetic interference, and chemical inertness. Therefore, fiber optic sensors have been developed to operate in harsh environments [ 19 , 20 ] and have shown reliability in measuring optical and mechanical variables such as refractive index [ 21 , 22 ], curvature [ 23 , 24 ], surface tension [ 25 , 26 ], and temperature [ 27 , 28 ]. Ratiometric sensing has been implemented in optical fibers to measure oxygen concentration [ 29 , 30 ], pH [ 31 , 32 , 33 ], and antibiotics [ 34 ].…”

Section: Introductionmentioning

confidence: 99%

Highly Coupled Seven-Core Fiber for Ratiometric Anti-Phase Sensing

Cuando-Espitia,

Camarillo-Avilés,

May-Arrioja

et al. 2023

A ratiometric fiber optic temperature sensor based on a highly coupled seven-core fiber (SCF) is proposed and experimentally demonstrated. A theoretical analysis of the SCF’s sinusoidal spectral response in transmission configuration is presented. The proposed sensor comprises two SCF devices exhibiting anti-phase transmission spectra. Simple fabrication of the devices is shown by just splicing a segment of a 2 cm long SCF between two single-mode fibers (SMFs). The sensor proved to be robust against light source fluctuations, as a standard deviation of 0.2% was registered in the ratiometric measurements when the light source varied by 12%. Its low-cost detection system (two photodetectors) and the range of temperature detection (25 °C to 400 °C) make it a very attractive and promising device for real industrial applications.