Publication Date:
2020-02-12
Description:
A new measurement method is presented utilizing glass fibers with inscribed Fiber Bragg Gratings (FBG). Strain and temperature changes have direct effects on these gratings. With this technology and suitable transducers, however, also parameters like pressure, dislocation, vibration, acceleration, humidity and even chemicals can be monitored. A broadband or sweeping laser light source is used and light with wavelengths corresponding to the FBGs is reflected back to a data acquisition unit (interrogator). Depending on variations of the parameter to be measured, the grating is stretched or compressed and as a result the reflected (Bragg) wavelength is shifted to longer or shorter wavelength respectively. This shift is proportional to the change of the parameters value. The fiber sensor or the transducers can be fixed, welded, glued onto or even embedded in the media, which shall be monitored. The biggest advantages of the technique are – A single fiber can carry a multitude of sensors, sensing is done simultaneously parallel (multiplexing). – The optically encoded signals of the measured parameters are transmitted in the fiber to the data acquisition unit. Thus, no additional data line is necessary. – The sensors have minimum volume with low weight, are flexible and easy to install. – Measuring with light does not require power for the sensors or the fibers, sensing is immune against electromagnetic interference (EMI) and intrinsically safe. Consequently, measurement can be done in places that are explosion-proof zones, exhibit strong magnetic fields or are not accessible anymore after the sensors have been installed. – Attenuation 0.1 dB/km only. Thus a measurement length of some 100 km can be realized.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
Format:
application/pdf
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