| Summary: | 碩士 === 國立清華大學 === 電機工程學系 === 92 === In this thesis, we propose a temperature-insensitive Fiber Bragg Grating strain sensor system, using the new method of detecting the optical power to determine the level of stresses. We achieve temperature insensitivity by using two optical fiber Bragg gratings with similar reflection spectra, and use an optical switch to achieve multi-point fiber bragg grating strain sensing.
In this thesis, we modify a previous measuring scheme to acquire a practice multi-point fiber bragg grating strain sensor. The new scheme is cost-effective .Compared with previous sensing schemes is no crosstalk, and easy to control. Our prototype is able to detect, separately, the changes of stresses at different positions.
As for the effects of power fluctuation, we also provide a solution in this thesis. We used a microprocessor to obtain a division circuit functionally in reducing the effect of power fluctuations .In the strain measurement schemes , we used an backward ASE of EDFA as a broadband light source, and then control microprocessor to choose the reflection signal we want via an optical switch. Then we had two optical signals input to optical photo detectors, and used the electric circuit which controlled by the microprocessor to process the data so that we can see information in the LCD.
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