scholarly journals Development of regenerated fiber Bragg grating sensors with long-term stability

2016 ◽  
Vol 24 (19) ◽  
pp. 21897 ◽  
Author(s):  
Mert Celikin ◽  
David Barba ◽  
Binod Bastola ◽  
Andreas Ruediger ◽  
Federico Rosei
Author(s):  
Jian-Neng Wang ◽  
Jaw-Luen Tang

A new high-resolution temperature and strain sensor with fiber Bragg grating (FBG) technology was developed. The FBG sensor consists of a reference fiber grating and a grating pair scheme that could offer the potential of simultaneous measurement of strain and temperature for monitoring pavement structures. Experimental results showed that measurement errors of ±μ∈ and ±0.13°C for strain and temperature could be achieved, respectively. Feasible applications of this sensor for monitoring pavement structures were investigated. The reliability and long-term stability tests for this sensor were examined by mounting it on the surface of two kinds of specimens, asphalt and concrete, and several temperature cycles with a designed working temperature range up to 110°C were applied for at least 24 h. An electronic thermocouple and a long-period optical fiber grating (LPG) sensor with similar function were used to compare the performance. Small root-mean-squared temperature variations (better than 1°C) and excellent long-term stability (within 2%) were obtained. The maximum variations in temperature for 48 h were only 1.94% and 2.32% for asphalt and concrete specimens, respectively. Results indicated that although the performance of this FBG sensor was comparable with that of the conventional thermocouple, its long-term stability was four times better than its counterpart, the LPG sensor. This type of simple and low-cost fiber-optic sensor is expected to benefit the developments and applications of new paving materials, mix design procedures, or the enhancement of pavement management systems.


2014 ◽  
Author(s):  
T. Habisreuther ◽  
T. Elsman ◽  
Z. Pan ◽  
A. Graf ◽  
P. Ahonen ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3635
Author(s):  
Takhmina Ayupova ◽  
Madina Shaimerdenova ◽  
Daniele Tosi

In this work, we present a gold-coated shallow-tapered chirped fiber Bragg grating (stCFBG) for dual refractive index (RI) and temperature sensing. The stCFBG has been fabricated on a 15-mm long chirped FBG, by tapering a 7.29-mm region with a waist of 39 μm. The spectral analysis shows two distinct regions: a pre-taper region, in which the stCFBG is RI-independent and can be used to detect thermal changes, and a post-taper region, in which the reflectivity increases significantly when the RI increments. We estimate the RI and thermal sensitivities as 382.83 dB/RIU and 9.893 pm/°C, respectively. The cross-talk values are low (−1.54 × 10−3 dB/°C and 568.1 pm/RIU), which allows an almost ideal separation between RI and thermal characteristics. The stCFBG is a compact probe, suitable for long-term and temperature-compensated biosensing and detection of chemical analytes.


1998 ◽  
Vol 531 ◽  
Author(s):  
A. Frank ◽  
Ph. M. Nellen ◽  
U. Sennhauser

AbstractFiber reinforced structural elements equipped with optical fiber sensors are of potential interest for long term surveillance of bridges, dams, and other civil engineering applications. We report herein on the embedding of optical fiber Bragg grating sensors into continuously pultruded glass fiber reinforced epoxy material (GFRP) rods used as structural elements.Two fibers, one with acrylic, one with polyimide coating, and fiber Bragg gratings were extensively characterized. The residual axial strain after embedding was measured. Temperature and strain coefficients of Bragg gratings during quasi-static cycling and temperature cycling tests were monitored and compared to extensometric and resistance strain gauge measurements.The effect of fiber embedding was also studied with push-out tests giving information about adhesion properties like surface bond energy, lateral stress, and coefficient of friction.For sensor purposes long term characteristics of the conversion factor between the measured Bragg grating wavelength and strain or temperature in the specimen have to be known to identify best-suited coatings for embedding and protecting fiber sensors and for obtaining reliability data on sensor performance.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3572
Author(s):  
Sandra Drusová ◽  
R. Martijn Wagterveld ◽  
Karel J. Keesman ◽  
Herman L. Offerhaus

Drinking water wells require continuous monitoring to prevent groundwater-related issues such as pollution, clogging and overdrafting. In this research, optical fibers with fiber Bragg grating sensors were placed in an aquifer to explore their potential use in long-term well monitoring. Fiber Bragg grating sensors were simultaneously sensitive to consolidation strain and temperature, and these two responses were separated by creating autoregressive consolidation models. Consolidation responses from these multiple sensors were rescaled to obtain pressure distribution along the depth. Pressure and temperature data showed impermeable soil layers and locations where groundwater accumulated. Time development of temperature along the fiber revealed oxidation of minerals and soil layers with varying permeability. Fiber Bragg grating sensors are useful tools to examine subsurface processes near wells and they can show the first signs of clogging.


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