scholarly journals Cladding Modified Fiber Bragg Grating for Copper Ions Detection

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Husam Abduldaem Mohammed ◽  
Aqiel Almamori ◽  
Ali A. Alwahib
Keyword(s):  
Fiber Bragg Grating ◽  
Copper Ions ◽  
Evanescent Field ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Chemical Agent ◽  
Toxic Heavy Metal ◽  
Fbg Sensor ◽  
Fbg Sensors ◽  
Significant Wavelength

This paper reports a fiber Bragg grating (FBG) as a biosensor. The FBGs were etched using a chemical agent,namely,hydrofluoric acid (HF). This implies the removal of some part of the cladding layer. Consequently, the evanescent field propagating out of the core will be closer to the environment and become more sensitive to the change in the surrounding. The proposed FBG sensor was utilized to detect toxic heavy metal ions aqueous medium namely, copper ions (Cu2+). Two FBG sensors were etched with 20 and 40 μm diameters and fabricated. The sensors were studied towards Cu2+ with different concentrations using wavelength shift as a result of the interaction between the evanescent field and copper ions. The FBG sensors showed a good response in terms of significant wavelength shift in corresponding to varying Cu2+ concentrations when immersed in aqueous mediums. The sensors exhibited excellent repeatability towards Cu ions.The results demonstrate that the smaller FBG etching diameter, the better optical response in terms of wavelength and linearity. 

scholarly journals Demonstration of a Filterless, Multi-Point, and Temperature-Independent Fiber Bragg Grating Dynamical Demodulator Using Pulse-Width Modulation

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5825
Author(s):  
Joao B. Rosolem ◽  
Marcio C. Argentato ◽  
Fábio R. Bassan ◽  
Rivael S. Penze ◽  
Claudio Floridia ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Optical Filter ◽  
Tunable Laser ◽  
Harsh Environments ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Fbg Sensor ◽  
Fbg Sensors

We demonstrated in this work a filterless, multi-point and temperature-independent FBG (fiber Bragg grating) dynamical demodulator using pulse-width-modulation (PWM). In this approach, the FBG interrogation system is composed of a tunable laser and a demodulator that is designed to detect the wavelength shift of the FBG sensor without any optical filter making it very suitable to be used in harsh environments. In this work, we applied the proposed method that uses the PWM technique for FBG sensors placed in high pressure and high-temperature environments. The proposed method was characterized in the laboratory using an FBG sensor modulated in a frequency of 6 Hz, with a 1 kHz sweeping frequency in the wavelength range from 1527 to 1534 nm. Also, the method was evaluated in a field test in an engine of a thermoelectric power plant.

Investigation on Temperature Compensation of Fiber Bragg Grating Sensors for Hull Monitoring

2018 ◽  
Author(s):  
Ruiqi Ma ◽  
Guoqing Feng ◽  
Huilong Ren ◽  
Peng Fu ◽  
Shuang Wu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Fiber Bragg Grating ◽  
Temperature Compensation ◽  
Compensation Method ◽  
Bragg Grating ◽  
Theoretical Derivation ◽  
Temperature Changes ◽  
Hull Girder ◽  
Fbg Sensor ◽  
Fbg Sensors

Hull monitoring system with Fiber Bragg Grating (FBG) sensors increasingly receives people’s attentions. However, for the ship hull monitoring, the deformation of hull girder changes a lot as is subjected to a huge temperature variation. Therefore, the compensation method with only FBG temperature self-correction is not suitable for the hull monitoring sensors because no material thermal expansion effects are reasonably included. In this paper, the new compensation method of hull monitoring FBG sensor based on the sensor theory with both FBG temperature self-correction and steel thermal expansion effects correction is studied. The coupled compensation method suitable for hull monitoring sensor is obtained by theoretical derivation. As the comparison, the coupled compensation experiment was carried out. The results show that the relative error under the temperature compensation method is large in the case of drastic strain and temperature changes, and the correction results of the tested method will be closer to the true level.

scholarly journals Femtosecond-Laser-Assisted Fabrication of Radiation-Resistant Fiber Bragg Grating Sensors

2022 ◽  
Vol 12 (2) ◽  
pp. 886
Author(s):  
Hun-Kook Choi ◽  
Young-Jun Jung ◽  
Bong-Ahn Yu ◽  
Jae-Hee Sung ◽  
Ik-Bu Sohn ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Fiber Bragg Grating ◽  
Optical Fibers ◽  
Coming Out ◽  
Single Mode ◽  
Femtosecond Laser Irradiation ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Radiation Resistant ◽  
Fbg Sensors

This paper demonstrates the fabrication of radiation-resistant fiber Bragg grating (FBG) sensors using infrared femtosecond laser irradiation. FBG sensors were written inside acrylate-coated fluorine-doped single-mode specialty optical fibers. We detected the Bragg resonance at 1542 nm. By controlling the irradiation conditions, we improved the signal strength coming out from the FBG sensors. A significant reduction in the Bragg wavelength shift was detected in the fabricated FBG sensors for a radiation dose up to 105 gray, indicating excellent radiation resistance capabilities. We also characterized the temperature sensitivity of the radiation-resistant FBG sensors and detected outstanding performance.

Detection of Pipeline Curvature with FBG Sensors Twisted

2013 ◽  
Vol 303-306 ◽  
pp. 67-73 ◽  
Author(s):  
Yan An Zhang ◽  
Zheng Liu ◽  
Lin Yong Shen ◽  
Jin Wu Qian
Keyword(s):  
Fiber Bragg Grating ◽  
Curve Fitting ◽  
Bragg Grating ◽  
Bending Deformation ◽  
Fbg Sensor ◽  
Underground Pipelines ◽  
Fbg Sensors ◽  
Simulation Results ◽  
Spatial Trajectory ◽  
Fitting Accuracy

In trenchless detection of underground pipelines, a method has been introduced which employs Fiber Bragg Grating (FBG) sensors to detect curvatures of the pipeline at discrete points and reconstructs the spatial trajectory of the pipeline by means of a newly developed approach. In measuring the pipeline curvature, the FBG sensor may be twisted besides sustaining bending deformation. This paper proposes a new algorithm for curvature calculation at discrete points, considering both overall revolving and partial twisting of the FBG sensors in order to enhance the curve fitting accuracy. Simulation results verify the effectiveness of the method.

Application of Fiber Bragg Grating Sensor coated with Polyaniline as an optical Sensor for chloroform detection

2017 ◽  
Vol 25 (7) ◽  
pp. 555-562
Author(s):  
Irma Zulayka Mohamad Ahad ◽  
Sulaiman Wadi Harun ◽  
Seng neon Gan ◽  
Sook Wai Phang
Keyword(s):  
Thin Film ◽  
Fiber Bragg Grating ◽  
Optical Sensor ◽  
Fast Response ◽  
Chemical Oxidation ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Peak Ratio ◽  
Bragg Wavelength ◽  
Fbg Sensor

Fiber Bragg Grating (FBG) sensor coated with PAni was designed as a sensing device in chloroform detection. PAni thin film was synthesized through chemical oxidation method by using aniline (Ani) as a monomer, ammonium persulphate (APS) as an initiator and dioctyl sodium sulfosuccinate (AOT) as a dopant. The chemical structure of PAni thin film was confirmed by using Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectrometer. The conducting behaviour of PAni thin film (1.157 × 10−2 S/cm) was determined by using four-point probe measurement. In the optical sensor part, FBG was etched in hydrofluoric acid solution (48% HF) to remove the cladding layer on fiber before coated with PAni. The response of this sensor was monitored based on the different of Bragg wavelength shift at ∼1557 nm in an optical spectrum analyzer (OSA) detector. PAni-coated FBG significantly increased in the Bragg wavelength shift (sensitivity = 0.0009) compared with uncoated FBG (sensitivity = 0.0002). The interaction between PAni and chloroform was significantly confirmed by the “polaron peak ratio” (Pf/Pi) and “quinoid and benzenoid peak ratio” (IQ/ IB) through UV-vis and FTIR spectroscopy analysis. In this study, FBG sensor coated with PAni thin film had been found as an efficient sensor in chloroform detection with fast response time (7 s).

Chemical Sensors Based on Fiber Bragg Grating

2011 ◽  
Vol 84-85 ◽  
pp. 582-585 ◽  
Author(s):  
Ming Fu Zhao ◽  
De Yi Huang ◽  
Bin Zhou ◽  
Lei Zi Jiao
Keyword(s):  
Refractive Index ◽  
Fiber Bragg Grating ◽  
Chemical Sensor ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Bragg Wavelength ◽  
Chemical Substances ◽  
Fbg Sensor ◽  
Surrounding Refractive Index ◽  
The Relationship

In this paper, measurement method for the refractive index of chemical substances based on fiber Bragg grating (FBG) sensor was proposed. The relation between Bragg wavelength shift and surrounding refractive index (SRI) was analyzed theoretically and experimentally. The SRI sensitivity of the chemical sensor could be enhanced by reducing the cladding thickness of the FBG using hydrofluoric acid (HF) solution etching process. The experimental results indicated that the variation of Bragg wavelength increased as the SRI increased. In the low SRI region, the relationship between the Bragg wavelength shift and the change of the SRI was approximately linear.

scholarly journals Real Time Monitoring of Railway Traffic Using Fiber Bragg Grating Sensors

2010 ◽  
Author(s):  
M. L. Filograno ◽  
A. Rodri´guez-Barrios ◽  
M. Gonza´lez-Herraez ◽  
P. Corredera ◽  
S. Marti´n-Lo´pez ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
High Speed ◽  
Field Tests ◽  
Bragg Grating ◽  
Railway Traffic ◽  
Fbg Sensor ◽  
Commercial Operation ◽  
Load Calculation ◽  
Different Types ◽  
Fbg Sensors

In this work we present field tests concerning the application of Fiber Bragg Grating (FBG) sensors for the monitoring of railway traffic. The test campaigns are performed on the Spanish high speed line Madrid–Barcelona, with different types of trains (S-102 TALGO–BOMBARDIER, S-103 SIEMENS-VELARO and S-120 CAF). We located the FBG sensors in the rail track at 70 km from Madrid in the country side, where the trains primarily are tested during commercial operation with maximum speeds between 250–300 km/h. The FBG sensor interrogation system used allows the simultaneous monitoring of four FBG sensors at 8000 samples/s. The different position of the FBG sensors in relation with the rail can be used with different purposes such as train identification, axle counting, speed and acceleration detection, wheel imperfections monitoring and dynamic load calculation.

scholarly journals Simultaneous Measurement of Temperature and Mechanical Strain Using a Fiber Bragg Grating Sensor

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4223
Author(s):  
Shiuh-Chuan Her ◽  
Wei-Nan Lin
Keyword(s):  
Theoretical Prediction ◽  
Fiber Bragg Grating ◽  
Mechanical Strain ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Physical Parameters ◽  
Bragg Wavelength ◽  
Fbg Sensor ◽  
Host Structure ◽  
As Stress

Based on the shift of the Bragg wavelength, fiber Bragg grating (FBG) sensors have been employed to measure a variety of physical parameters such as stress, strain, displacement, temperature, vibration and pressure. In this work, a simple and easy way to be implemented FBG sensing methodology was proposed to measure the temperature and strain simultaneously. Half of the FBG was bonded on the host structure, while the other half of the FBG was left free. The host structure was an aluminum test specimen with dimensions of 20 × 3.8 × 0.5 cm3. As the host structure subjected to mechanical and thermal loadings, the Bragg wavelengths reflected from the bonded and unbonded FBGs are different. Theoretical predictions of the Bragg wavelength shifts of the bonded and unbonded FBGs were presented. Utilizing the Bragg wavelength shift of unbonded FBG, the temperature can be determined and is independent of mechanical strain. The Bragg wavelength shift of the bonded FBG allows the determination of the mechanical strain. The temperature measured by FBG sensor was compared with the result from a thermocouple, while the mechanical strain was validated with the theoretical prediction. Good agreement between the experimental measurement and theoretical prediction demonstrates that temperature-strain discrimination can be realized using the proposed method with one single FBG sensor.

Smart Structural Health Monitoring Based on Detecting Picometer-Scale Wavelength Shift of Fiber Bragg Grating

2013 ◽  
Vol 562-565 ◽  
pp. 1346-1352
Author(s):  
Jun Jie Bai ◽  
Jian Xing Li ◽  
Jun Zhang ◽  
Xiao Yun Zhang ◽  
Le Wang ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Sensor Network ◽  
Health Monitoring ◽  
High Speed ◽  
Smart Structure ◽  
Comb Filter ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Center Wavelength ◽  
Fbg Sensor

The real-time monitoring technologies of smart civil structure based on detecting picometer-scale wavelength shift of fiber Bragg grating (FBG), including the wavelength demodulation technology of FBG, are researched extensively at home and abroad. In the paper, using the technologies of wavelength division multiplex (WDM) and time division multiplex (TDM), fiber Bragg grating (FBG) sensor network was built for monitoring smart structure health condition. Based on SOPC (System on Programmable Chip) technology and fiber comb filter, a high-speed and high-precision wavelength demodulation scheme of FBG sensor network was proposed. The optical system and hardware circuit for demodulation system were designed specifically. To improve the accuracy of demodulation system of FBG, a constant temperature channel of the demodulation system connected with a fiber comb filter, which offered reference points to calibrate the Bragg grating center wavelength. Based on 32-bit soft-core processor NoisⅡ, the embedded system collected and processed the photoelectric signal voltage transformed to rectangular voltage pulse. The upper computer displayed dynamically the FBG wavelength demodulation process and calibrated the Bragg grating center wavelength. The experiments of FBG wavelength demodulation and health monitoring of smart structural embedded fiber Bragg gratings were done. Experimental results show that, the FBG wavelength demodulation method can be used to demodulate the FBG wavelength with high speed and high precision (± 2 pm), which can be used extensively in large-scale multipoint monitor engineering, and the strains of the smart structure can be measured accurately.

scholarly journals Design Reliable Bus Structure Distributed Fiber Bragg Grating Sensor Network Using Gated Recurrent Unit Network

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7355
Author(s):  
Amare Mulatie Dehnaw ◽  
Yibeltal Chanie Manie ◽  
Ya Yu Chen ◽  
Po Han Chiu ◽  
Hung Wei Huang ◽  
...  
Keyword(s):  
Sensor Networks ◽  
Fiber Bragg Grating ◽  
Wavelength Division Multiplexing ◽  
Bragg Grating ◽  
Bragg Wavelength ◽  
Wavelength Division ◽  
Fbg Sensor ◽  
Bus Structure ◽  
Fbg Sensors ◽  
Gated Recurrent Unit

The focus of this paper was designing and demonstrating bus structure FBG sensor networks using intensity wavelength division multiplexing (IWDM) techniques and a gated recurrent unit (GRU) algorithm to increase the capability of multiplexing and the ability to detect Bragg wavelengths with greater accuracy. Several Fiber Bragg grating (FBG) sensors are coupled with power ratios of 90:10 and 80:10, respectively in the suggested experimental setup. We used the latest IWDM multiplexing technique for the proposed scheme, as the IWDM system increases the number of sensors and allows us to alleviate the limited operational region drawback of conventional wavelength division multiplexing (WDM). However, IWDM has a crosstalk problem that causes high-sensor signal measurement errors. Thus, we proposed the GRU model to overcome this crosstalk or overlapping problem by converting the spectral detection problem into a regression problem and considered the sequence of spectral features as input. By feeding this sequential spectrum dataset into the GRU model, we trained the GRU system until we achieved optimal efficiency. Consequently, the well-trained GRU model quickly and accurately identifies the Bragg wavelength of each FBG from the overlapping spectra. The Bragg wavelength detection performance of our proposed GRU model is tested or validated using different numbers of FBG sensors, such as 3-FBG, 5-FBG, 7-FBG, and 10-FBG, separately. As a result, the experiment result proves that the well-trained GRU model accurately identifies each FBG Bragg wavelength, and even the number of FBG sensors increase, as well as the spectra of FBGs, which are partially or fully overlapped. Therefore, to boost the detection efficiency, reliability, and to increase the multiplexing capabilities of FBG sensor networks, the proposed sensor system is better than the other previously proposed methods.

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