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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.430-432.1211 ◽

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.

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

Sensors ◽

10.3390/s18124478 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4478 ◽

Cited By ~ 4

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.

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