Tunable chirping of a fiber Bragg grating without center wavelength shift using a simply supported beam

2002 ◽  
Vol 41 (4) ◽  
pp. 740 ◽  
Author(s):  
Yunqi Liu
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Center Wavelength ◽  
Simply Supported Beam ◽  
Simply Supported

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.

Development of Fiber Bragg Grating (FBG) as Temperature Sensor Inside Packed-bed Non-thermal Plasma Reactor

2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Siti Musliha Aishah Musa ◽  
RK Raja Ibrahim ◽  
Asrul Izam Azmi
Keyword(s):  
Fiber Bragg Grating ◽  
Temperature Variation ◽  
Thermal Plasma ◽  
Temperature Sensor ◽  
Plasma Reactor ◽  
Packed Bed ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Bragg Wavelength ◽  
Non Thermal Plasma

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.

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.

scholarly journals Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5469
Author(s):  
Xiuxiu Xu ◽  
Mingming Luo ◽  
Jianfei Liu ◽  
Nannan Luan
Keyword(s):  
Fiber Bragg Grating ◽  
Humidity Sensor ◽  
Field Tests ◽  
Polyimide Film ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Sensing Applications ◽  
Fluorinated Polyimide ◽  
Temperature And Humidity ◽  
Fluoride Doping

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.

Fiber ring-cavity laser based on semiconductor optical amplifier

2018 ◽  
Vol 32 (24) ◽  
pp. 1850266
Author(s):  
Min Luo ◽  
Wei Cao ◽  
Haiyan Chen
Keyword(s):  
Quantum Wells ◽  
Fiber Bragg Grating ◽  
Semiconductor Optical Amplifier ◽  
Operating Temperature ◽  
Ring Cavity ◽  
Optical Amplifier ◽  
Injection Current ◽  
Bragg Grating ◽  
Center Wavelength ◽  
Fiber Ring

A fiber ring-cavity laser based on InP/InGaAsP multi-quantum wells semiconductor optical amplifier is proposed and experimentally demonstrated. The laser uses InP/InGaAsP multi-quantum as well as the gain medium and fiber Bragg grating as the wavelength selector. It’s demonstrated that the center wavelength of the output amplified spontaneous emission spectrum for the InP/InGaAsP multiple-quantum wells appears blue shift when its injection current increases. A lasing at central wavelength of 1549.66 nm with the maximum output power of 1.524 mW is obtained with electro-optical efficiency of 1.1% at injection current of 220 mA and the fiber Bragg grating operating temperature of 23[Formula: see text]C. The threshold injection current of the laser is 78 mA. When the operating temperature of fiber Bragg grating increases from 8[Formula: see text]C to 28[Formula: see text]C, the center wavelength of output laser increases from 1549.27 to 1549.59 nm. It shows that the laser has good temperature stability.

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.

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