Fiber Bragg Grating Wavelength Shift Measurement Method Based on Cross spectrum Detection and Crosscorrelation Technology

2014 ◽  
Vol 43 (6) ◽  
pp. 606004
Author(s):  
李智忠 LI Zhizhong ◽  
许忠良 XU Zhongliang ◽  
李海涛 LI Haitao ◽  
程玉胜 CHENG Yusheng ◽  
史秋亮 SHI Qiuliang
2018 ◽  
Vol 28 (2) ◽  
pp. 139
Author(s):  
Pham Van Hoi ◽  
Nguyen Thuy Van ◽  
Pham Van Dai ◽  
Le Huu Thang ◽  
Nguyen Van An ◽  
...  

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:


2012 ◽  
Vol 239-240 ◽  
pp. 156-162
Author(s):  
Fan Yang ◽  
Biao Wei

In order to improve the signal demodulation performance of fiber Bragg grating (FBG) sensing system, a wavelength shift detection method based on cross-correlation analysis is proposed to improve the accuracy of the measurement. The simulation results indicate that the absolute error of the measurement can be between 2 pm - 3 pm within the range of SNR of 14 dB-7 dB. Under the condition with high SNR, the absolute error can be approximately reduced to 0.5 pm. Hence, this demodulation algorithm can reduce the influences of the noises effectively and help to further study the features of the FBG sensor demodulation system.


2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Siti Musliha Aishah Musa ◽  
RK Raja Ibrahim ◽  
Asrul Izam Azmi

This paper presents early work on Fiber Bragg grating (FBG) as temperature sensor to monitor temperature variation inside a packed-bed non-thermal plasma reactor. FBG made from germania-doped fiber with center Bragg wavelength of 1552.5 nm was embedded inside non-thermal plasma reactor with sphere shape dielectric bead (barium titanate) and used to probe the temperature variation inside the reactor. The experimental works have proven that FBG is a suitable sensor to monitor temperature variation inside of reactor via LabVIEW program. Besides that, Optical Spectrum Analyzer (OSA) recorded Bragg wavelength shift as voltage of power supply increases, which indicate the non-uniform temperature variation occurring inside the reactor. However, it does not affect the chemical reaction inside the reactor because the temperature condition is in steady state.


2022 ◽  
Vol 12 (2) ◽  
pp. 886
Author(s):  
Hun-Kook Choi ◽  
Young-Jun Jung ◽  
Bong-Ahn Yu ◽  
Jae-Hee Sung ◽  
Ik-Bu Sohn ◽  
...  

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.


2020 ◽  
Vol 91 (1) ◽  
pp. 015007
Author(s):  
Chi Wang ◽  
Yidong Zhang ◽  
Jianmei Sun ◽  
Chenye Yang ◽  
Xuan Ren ◽  
...  

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5469
Author(s):  
Xiuxiu Xu ◽  
Mingming Luo ◽  
Jianfei Liu ◽  
Nannan Luan

We propose and demonstrate a temperature and humidity sensor based on a fluorinated polyimide film and fiber Bragg grating. Moisture-induced film expansion or contraction causes an extra strain, which is transferred to the fiber Bragg grating and leads to a humidity-dependent wavelength shift. The hydrophobic fluoride doping in the polyimide film helps to restrain its humidity hysteresis and provides a short moisture breathing time less than 2 min. Additionally, another cascaded fiber Bragg grating is used to exclude its thermal crosstalk, with a temperature accuracy of ±0.5 °C. Experimental monitoring over 9000 min revealed a considerable humidity accuracy better than ±3% relative humidity, due to the sensitized separate film-grating structure. The passive and electromagnetic immune sensor proved itself in field tests and could have sensing applications in the electro-sensitive storage of fuel, explosives, and chemicals.


Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4478 ◽  
Author(s):  
Jiachen Yu ◽  
Zhenlin Wu ◽  
Xin Yang ◽  
Xiuyou Han ◽  
Mingshan Zhao

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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