scholarly journals Tilted Fiber Bragg Grating Sensor Using Chemical Plating of a Palladium Membrane for the Detection of Hydrogen Leakage

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4478 ◽  
Author(s):  
Jiachen Yu ◽  
Zhenlin Wu ◽  
Xin Yang ◽  
Xiuyou Han ◽  
Mingshan Zhao
Keyword(s):  
Fiber Bragg Grating ◽  
Low Cost ◽  
Hydrogen Sensor ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Cross Sensitivity ◽  
Chemical Plating ◽  
Palladium Membrane ◽  
Surrounding Refractive Index ◽  
The Cross

A tilted fiber Bragg grating (TFBG) hydrogen sensor coated with a palladium (Pd) membrane by the electroless plating method is proposed in this paper. A uniform layer of Pd metal is fabricated in aqueous solutions by the chemical coating method, which is used as the sensitive element to detect the change of the surrounding refractive index (SRI) caused by hydrogen absorption. The change in SRI causes an unsynchronized change of the cladding modes and the Bragg peak in the TFBG transmission spectrum, thereby eliminating the cross-sensitivity due to membrane expansion and is able to simultaneously monitor the presence of cracks in the pipe, as well as the hydrogen leakage. By subtracting the wavelength shift caused by fiber expansion, the change of SRI, i.e., the information from the H2 level, can be separately obtained. The drifted wavelength is measured for the H2 concentration below the hydrogen explosion limit between 1% and 4%. The chemical-based coating has the advantages of a low cost, a simple operation, and being suitable for coating on long fiber structures. The proposed sensor is able to detect the H2 signal in 5 min at a 1% H2 concentration. The proposed sensor is proved to be able to monitor the hydrogen level without the cross-sensitivity of temperature variation and expansion strains, so could be a good candidate for security applications in industry.

scholarly journals Wavelength Shift Measurement Method Without Use of Spectrometer: The New Way for Environment Photonic Sensors

2018 ◽  
Vol 28 (2) ◽  
pp. 139
Author(s):  
Pham Van Hoi ◽  
Nguyen Thuy Van ◽  
Pham Van Dai ◽  
Le Huu Thang ◽  
Nguyen Van An ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Low Cost ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Shift Measurement ◽  
Liquid Environment ◽  
Mixing Ratios ◽  
Narrow Line Width ◽  
Photonic Sensors ◽  
Testing Environments

The photonic sensors have shown very effectively for measuring the toxic contents in the liquid and air environments. In principle, the photonic sensors based on measurement of wavelength shift between reference condition and testing environments that we need use the spectrometer with high cost. In this paper, we present new configurations of photonic devices for measuring wavelength shift without use of spectrometer, which has a large potential for application in sensing technique with low cost. There are two configurations of photonic sensors are presented: i) first of them is based on fiber Bragg grating (FBG) combined with DFB laser diode with controlling wavelength emission by laser temperature and ii) second one is used  the fiber ring laser from Erbium-doped fiber and two FBG operated as  reference and sensing probe. The etched-fiber Bragg grating (e-FBG) as sensing probe is suitable for bio- and/ or chemical sensors. A novel photonic sensor can increase sensitivity and measuring accuracy of device by the narrow line-width of reflection spectra from laser and the sensor can determine a refractive index variation of 2x10-4, which is similarly for high resolution spectrometer. The experimental results show that this sensing method could determine different mixing ratios of organic solvents in liquid environment with good repeatability, high accuracy and rapid response.Keywords:

Research on Measurement of Fiber Bragg Grating Considering the Cross-Sensitivity of Temperature and Strain

2018 ◽  
Vol 55 (2) ◽  
pp. 020605
Author(s):  
丁朋 Ding Peng ◽  
董小鹏 Dong Xiaopeng ◽  
叶肖伟 Ye Xiaowei
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Cross Sensitivity ◽  
The Cross

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 Temperature Self-Compensated Refractive Index Sensor Based on Fiber Bragg Grating and the Ellipsoid Structure

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5211 ◽  
Author(s):  
Binbin Yan ◽  
Lei Sun ◽  
Yanhua Luo ◽  
Liwei Yang ◽  
Haifeng Qi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fiber Bragg Grating ◽  
Resonant Peak ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Refractive Index Sensor ◽  
Average Sensitivity ◽  
Surrounding Refractive Index ◽  
Index Unit ◽  
Sensing Performance

In this paper, a temperature self-compensated refractive index sensor based on fiber Bragg grating (FBG) and the ellipsoid structure is demonstrated. The ellipsoid can excite the cladding modes and recouple them into the fiber core. Two well-defined wavelength bands are observed in the reflection spectrum of the proposed sensor, i.e., the Bragg resonant peak and the cladding resonant peaks. By measuring the wavelength shift of the cladding resonant peak, the surrounding refractive index (SRI) can be determined, and the wavelength shift of the Bragg resonant peak can be used as a reliable reference to self-compensate the temperature variation (temperature sensitivity of 10.76 pm/°C). When the SRI changes from 1.3352 to 1.3722, the cladding resonant peak redshifts linearly with an average sensitivity of 352.6 pm/RIU (refractive index unit). When the SRI changes from 1.3722 to 1.4426, an exponential redshift is observed with a maximum sensitivity of 4182.2 pm/RIU. Especially, the sensing performance is not very reliant on the distance between the FBG and the ellipsoid, greatly improving the ease of the fabrication.

A Modified Dual-Wavelength Matrix Calculation Method for Fiber Bragg Grating (FBG)

2012 ◽  
Vol 430-432 ◽  
pp. 1211-1214
Author(s):  
Xin Liu
Keyword(s):  
Fiber Bragg Grating ◽  
Calculation Method ◽  
Dual Wavelength ◽  
Fiber Sensor ◽  
Bragg Grating ◽  
Fiber Grating ◽  
Cross Sensitivity ◽  
Sensitivity Problem ◽  
The Cross ◽  
Matrix Calculation

Fiber grating is an optical passive device which is developed very fast in recent years. FBG is the most grating which is used as fiber sensor. Cross-sensitivity of fiber grating sensor is an important problem which is restricted the development of the fiber sensor. We do a deep research on the cross-sensitivity problem of the Fiber Bragg grating in this paper. Based on the basic principle of how the cross-sensitivity problem is produced, we suggest a modification in a dual-wavelength matrix calculation method which is used to solve the cross-sensitivity problem in traditional. The modified dual-wavelength matrix calculation method has a higher accuracy than the traditional method.

Modeling of Fiber Bragg Grating Hydrogen Sensor with Multiple Membranes

2015 ◽  
Vol 738-739 ◽  
pp. 15-18
Author(s):  
Ying Ting Luo ◽  
Hao Wu ◽  
Yong Huang ◽  
Xiong Li ◽  
Hong Tu Song ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Partial Pressure ◽  
Fiber Bragg Grating ◽  
Hydrogen Concentration ◽  
Linear Response ◽  
Hydrogen Sensor ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Low Concentration ◽  
The Relationship

This paper develops a multiple membranes fiber Bragg grating (FBG) hydrogen sensor and investigates the relationship between wavelength of FBG hydrogen sensor and ambient hydrogen concentration. A physical and mathematical model is built to explain the sensor behavior when it is subjected to the changes in hydrogen concentration and in temperature. The shifts in Bragg wavelengths of the Pd-coated FBG hydrogen sensor as a function of hydrogen partial pressure is obtained. Thus the developed FBG hydrogen sensor has a linear response to hydrogen in the low concentration range. Tests were carried on to prove the relationship between wavelength shift and hydrogen concentration.

scholarly journals Determination of Wavelength Shift of Fiber Bragg Grating Sensors by Tunable Single-mode Diode Laser

2013 ◽  
Vol 23 (1) ◽  
pp. 75
Author(s):  
Nguyen The Anh ◽  
Pham Thanh Son ◽  
Nguyen Thuy Van ◽  
Hoang Thi Hong Cam ◽  
Ngo Quang Minh ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Low Cost ◽  
Broad Band ◽  
Single Mode ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Physical Parameters ◽  
Lasing Wavelength ◽  
Dfb Laser

We propose a novel principle of determination of fiber Bragg grating (FBG) wavelength shift which is impacted by a variation of physical parameters such as temperature, pressure and/or strain. In common case the wavelength shift of FBG was monitored by wavelength measurement using a high-cost spectrometer and a broad band light source. In our proposed technique the wavelength shift of FBG can be determined by change of lasing wavelength of distributed feedback laser (DFB-laser) due to the change of laser substrate temperature. The maximal opto-electrical intensity of photodetector would be obtained when the laser wavelength and FBG reflection wavelength are coincided. The FBG sensor prototype has shown excellent response for laser temperature change in the range of \(10^{\circ}C-50^{\circ}C\) with the ratio \(\Delta \lambda /\Delta T\) of the DFB laser is of 77.5 pm.K\(^{ - 1}\). Key features of the proposed technique are fabrication of low-cost FBG sensors for civil engineering.

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