Long-term thermal stability tests at 1000 degree C of silica fiber Bragg grating made with ultrafast laser radiation

2005 ◽  
Author(s):  
Dan Grobnic ◽  
Christopher W. Smelser ◽  
Stephen J. Mihailov ◽  
Robert B. Walker
Keyword(s):  
Thermal Stability ◽  
Laser Radiation ◽  
Fiber Bragg Grating ◽  
Ultrafast Laser ◽  
Silica Fiber ◽  
Bragg Grating ◽  
Stability Tests

scholarly journals Fiber Bragg grating fabrication by femtosecond laser radiation

2019 ◽  
Vol 220 ◽  
pp. 03007
Author(s):  
Anton Chernikov ◽  
Dmitriy Kochuev ◽  
Kirill Khorkov ◽  
Ruslan Chkalov ◽  
Nikolay Davydov
Keyword(s):  
Laser Radiation ◽  
Femtosecond Laser ◽  
Fiber Bragg Grating ◽  
Fiber Optic ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Fiber Optic Sensors ◽  
Bragg Grating ◽  
Femtosecond Laser Radiation ◽  
Grating Fabrication

The paper presents the results of fiber Bragg gratings fabrication by femtosecond laser radiation using point-by-point and line-by-line inscription methods. The approach makes it possible to fabricate the second and higher diffraction orders fiber Bragg gratings, which can be used as sensitive elements of fiber-optic sensors.

scholarly journals Observing the Viscous Relaxation Process of Silica Optical Fiber at ~1000 °C Using Regenerated Fiber Bragg Grating

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2293 ◽  
Author(s):  
Zhiru Cui ◽  
Jianhui Gong ◽  
Chen Wang ◽  
Nana Che ◽  
Yanshuang Zhao ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Relaxation Process ◽  
Fiber Bragg Grating ◽  
Active Role ◽  
Silica Fiber ◽  
Bragg Grating ◽  
Optical Fiber Devices ◽  
Two Factors ◽  
Silica Optical Fiber ◽  
Viscous Relaxation

A regenerated fiber Bragg grating (RFBG) in silica fiber was used to observe the viscous relaxation process of the host silica fiber at high temperatures of around 1000 °C. Two factors, preannealing time and loaded tension, which affect viscous relaxation, were observed. When an RFBG is stretched after a longer preannealing, the measured viscosity of the optical fiber was observed to reach equilibrium faster, which means that preannealing accelerates viscous relaxation. A similar acceleration phenomenon was also observed when a larger load was applied to stretch the optical fiber, although the acceleration effect of loaded tension was not as strong as in the preannealing case. The results play an active role in establishing effective optical-fiber devices for application in high-temperature environments.

Long-term stable sapphire fiber Bragg grating sensors at 1400°C

2014 ◽  
Author(s):  
T. Habisreuther ◽  
T. Elsman ◽  
Z. Pan ◽  
A. Graf ◽  
P. Ahonen ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
Sapphire Fiber

FBG Earth Pressure Sensors Applied in Surrounding Rock Pressure of Tunnel

2013 ◽  
Vol 351-352 ◽  
pp. 1173-1178
Author(s):  
Zhou Chun Cai ◽  
Chuan Li ◽  
Yuan Yu Guan ◽  
Wu Fen Chen ◽  
Li Jun Guo ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Rock Pressure ◽  
Pressure Sensors ◽  
Earth Pressure ◽  
Surrounding Rock ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Stress Changes ◽  
Surrounding Rock Pressure

During the period of tunnel excavation, shoring, forming and long-term operation, stress changes of tunnel surrounding rock are complex, the real-time monitoring of surrounding rock pressure is the key factor in ensuring long-term stability in tunnel. Fiber Bragg grating earth pressure sensors apply in surrounding rock pressure of tunnel which can change the pressure of the surrounding rock into fiber Bragg grating wavelength shift. According to the feature of pressure and temperature in Tian Xin Tunnel, 40 earth pressure sensors are embedded in 20 representative sections and one earth pressure sensor is embedded in each arch shoulder. In addition, one temperature compensation sensor is embedded in each arch crown. During the 235 monitoring days, the biggest daily change of surrounding rock pressure reaches 800 KPa. In 3 months of the sensor installation, the average monthly variation is within 50 KPa. The long-term measurement results indicate that the changes of surrounding rock pressure are different in different locations. When the surrounding rock is close to the excavated and blasted surface the surrounding rock pressure changes largely.

Using Fiber Bragg Grating Sensors to Monitor Pavement Structures

2005 ◽  
Vol 1913 (1) ◽  
pp. 165-176 ◽  
Author(s):  
Jian-Neng Wang ◽  
Jaw-Luen Tang
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Fiber Grating ◽  
Term Stability ◽  
Long Term Stability ◽  
Fbg Sensor ◽  
Lpg Sensor ◽  
Pavement Structures ◽  
Better Than

A new high-resolution temperature and strain sensor with fiber Bragg grating (FBG) technology was developed. The FBG sensor consists of a reference fiber grating and a grating pair scheme that could offer the potential of simultaneous measurement of strain and temperature for monitoring pavement structures. Experimental results showed that measurement errors of ±μ∈ and ±0.13°C for strain and temperature could be achieved, respectively. Feasible applications of this sensor for monitoring pavement structures were investigated. The reliability and long-term stability tests for this sensor were examined by mounting it on the surface of two kinds of specimens, asphalt and concrete, and several temperature cycles with a designed working temperature range up to 110°C were applied for at least 24 h. An electronic thermocouple and a long-period optical fiber grating (LPG) sensor with similar function were used to compare the performance. Small root-mean-squared temperature variations (better than 1°C) and excellent long-term stability (within 2%) were obtained. The maximum variations in temperature for 48 h were only 1.94% and 2.32% for asphalt and concrete specimens, respectively. Results indicated that although the performance of this FBG sensor was comparable with that of the conventional thermocouple, its long-term stability was four times better than its counterpart, the LPG sensor. This type of simple and low-cost fiber-optic sensor is expected to benefit the developments and applications of new paving materials, mix design procedures, or the enhancement of pavement management systems.

On-Line Monitoring of Charge Unit by Using Fiber Bragg Grating Temperature Sensors

2012 ◽  
Vol 503-504 ◽  
pp. 1672-1678
Author(s):  
Zhao Yang ◽  
Xiao Ping Xu ◽  
Chuan Li ◽  
Yan Chen ◽  
Jiang Chun Xu ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Fiber Bragg Grating ◽  
Minimum Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Bragg Grating ◽  
Temperature Changes ◽  
Temperature Range ◽  
On Line

The charge unit supply power when the power is cut off. It has been the necessary components in every type of substations to ensure the continuous operations of electric relays, automatic devices and circuit breakers. By using contacting electrical insulating Fiber Bragg Grating temperature sensor, the monitored equipment can be measured and controlled under the safe temperature. The temperatures of three fans and environment have been surveyed since June 6, 2010, in the charge unit of Yanjin substation’s main control room. The real-time monitoring of 24-hours indicates that the temperature changes in the range of 1°C. At the long-term of 479 days, the average daily minimum temperature range of three fans is 12.48°C, and the maximum range is 23.07°C. The maximum temperature is 39.14°C on April 30, 2011, and the minimum temperature is 23.98°C on January 10, 2011. The daily average of ambient temperature range is 12.04 °C, the maximum temperature is 38.38 °C on July 16, 2010, and the minimum temperature is 26.34 °C on January 9, 2011. The maximum difference between the temperature of fan and the ambient temperature is 7.60 °C on October 23, 2010. According to the relevant standards and monitoring results, the maximum threshold of fan temperature is defined to 85°C, and the threshold of temperature rise is 20°C.

scholarly journals Field Deployable Fiber Bragg Grating Strain Patch for Long-Term Stable Health Monitoring Applications

2013 ◽  
Vol 3 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Vivien Schukar ◽  
Nadine Kusche ◽  
Gerhard Kalinka ◽  
Wolfgang Habel
Keyword(s):  
Fiber Bragg Grating ◽  
Health Monitoring ◽  
Bragg Grating ◽  
Monitoring Applications

Study on Buried Pipeline Security and Early-Warning System in Landslide Area Based on Fiber Bragg Grating Sensors

2008 ◽  
Author(s):  
Jianping Liu ◽  
Hongju Wang ◽  
Jianbin Hao ◽  
Pengchao Chen ◽  
Muyang Ai
Keyword(s):  
Fiber Bragg Grating ◽  
Electromagnetic Interference ◽  
Surface Displacement ◽  
Warning System ◽  
Bragg Grating ◽  
Buried Pipeline ◽  
Fbg Sensors ◽  
Long Term Monitoring ◽  
Term Monitoring

Compared with electric sensors, Fiber Bragg Grating (FBG) sensors are immune to electromagnetic interference, corrosion resistant, small in size and light in weight. Therefore, FBG sensors are easy to bury into geotechnical soil mass, measuring strain and temperature simultaneously. Focused on buried pipeline integrity, a type of sensing network made up of FBG sensors is introduced in this paper, monitoring pipeline strain, landslide surface displacement and inner displacement. An application of the sensing network to a huge landslide affecting a gas mainline is also introduced. The field experimental data show that, the FBG sensors have many advantages such as good real-time monitoring ability, flexible to develop sensing network, convenient to realize long-term monitoring. Moreover, the FBG sensors give reliable long-term monitoring data of pipeline strain and surface and inner displacement of the landslide, which provide the basis to evaluate pipelines integrity affected by landslides.

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