Long-term stable sapphire fiber Bragg grating sensors at 1400°C

2014 ◽  
Author(s):  
T. Habisreuther ◽  
T. Elsman ◽  
Z. Pan ◽  
A. Graf ◽  
P. Ahonen ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
Sapphire Fiber

scholarly journals Shallow-Tapered Chirped Fiber Bragg Grating Sensors for Dual Refractive Index and Temperature Sensing

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3635
Author(s):  
Takhmina Ayupova ◽  
Madina Shaimerdenova ◽  
Daniele Tosi
Keyword(s):  
Refractive Index ◽  
Spectral Analysis ◽  
Fiber Bragg Grating ◽  
Thermal Characteristics ◽  
Temperature Sensing ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
Thermal Changes ◽  
Chirped Fiber Bragg Grating

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.

Characterization of Embedded Optical Fiber Bragg Grating Sensors

1998 ◽  
Vol 531 ◽  
Author(s):  
A. Frank ◽  
Ph. M. Nellen ◽  
U. Sennhauser
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Bragg Gratings ◽  
Bragg Grating ◽  
Structural Elements ◽  
Fiber Reinforced ◽  
Fiber Sensors ◽  
Fiber Bragg Grating Sensors ◽  
Optical Fiber Bragg Grating

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.

scholarly journals Temperature and Consolidation Sensing Near Drinking Water Wells Using Fiber Bragg Grating Sensors

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3572
Author(s):  
Sandra Drusová ◽  
R. Martijn Wagterveld ◽  
Karel J. Keesman ◽  
Herman L. Offerhaus
Keyword(s):  
Drinking Water ◽  
Fiber Bragg Grating ◽  
Optical Fibers ◽  
Bragg Grating ◽  
Soil Layers ◽  
Multiple Sensors ◽  
Fiber Bragg Grating Sensors ◽  
Water Wells ◽  
Potential Use

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.

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
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Term Stability ◽  
Long Term Stability ◽  
Fiber Bragg Grating Sensors

scholarly journals Fiber Bragg Grating Sensors for Underwater Vibration Measurement: Potential Hydropower Applications

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4272
Author(s):  
Oscar de la Torre ◽  
Ignazio Floris ◽  
Salvador Sales ◽  
Xavier Escaler
Keyword(s):  
Fiber Bragg Grating ◽  
Numerical Models ◽  
Vibration Measurement ◽  
Quality Data ◽  
Bragg Grating ◽  
Laser Vibrometer ◽  
Main Concern ◽  
High Expectations ◽  
Fiber Bragg Grating Sensors ◽  
Hydraulic Machinery

The present paper assesses the performance and characteristics of fiber Bragg grating sensors, with a special interest in their applications in hydraulic machinery and systems. The hydropower industry is turning to this technology with high expectations of obtaining high quality data to validate and calibrate numerical models that could be used as digital twins of key assets, further strengthening the sector’s relevant position within industry 4.0. Prior to any validation, fiber Bragg grating sensors’ ability to perform well underwater for long periods of time with minimal degradation, and their ease of scalability, drew the authors´ attention. A simplified modal analysis of a partially submerged beam is proposed here as a first step to validate the potential of this type of technology for hydropower applications. Fiber Bragg grating sensors are used to obtain the beam’s natural frequencies and to damp vibrations under different conditions. The results are compared with more established waterproof electric strain gauges and a laser vibrometer with good agreement. The presence of several sensors in a single fiber ensures high spatial resolution, fundamental to precisely determine vibration patterns, which is a main concern in this industry. In this work, the beam’s vibration patterns have been successfully captured under different excitations and conditions.

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