能量調變型光纖光柵感測器在動態系統的實驗量測

The Measurements of Dynamics Responses by Power Modulated Fiber Gratting Sensors

許碩修(Shuo-Hsiu Hsu)

指導教授 ： 馬劍清

國立臺灣大學/工學院/機械工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00407

摘要

光纖光柵在應變感測上具有抗電磁干擾以及高靈敏度的特性，但發展至今在真正的動態量測應用上仍然有因難，主要的問題在於光柵訊號解讀的速度和精確度。能量調變型光纖光柵感測器原理是利用布拉格光纖光柵作應變感測、長週期光纖光柵做能量調變，藉此解讀光柵在受應力後訊號的改變，有反應速度快、解析度高以及架設簡單等優點。本論文將能量調變型光纖光柵感測器系統做改進後，利用一些實驗探討其應變量測能力。實驗搭配雷射都卜勒振動儀、雷射位移計、應變規以及阻抗分析儀等。除了定性的能力之外，建立定量方法達到定量量測，另外以分波的方式達到多工的效果，提升其實用性。
實驗的進行由靜態開始，接著是穩態應變量測，而最高頻可達到約160000 Hz，最後則是針對暫態訊號做量測能力的研究。

關鍵字

光纖光柵 ； 能量調變 ； 布拉格光纖光柵 ； 長週期式光纖光柵

並列摘要

The application of fiber gratings on strain sensing system has the advantages of electromagnetic immunity and high sensitivity. However, the capability on the measurement of dynamic response is still questionable. The main problem is the speed and accuracy of reading fiber gratings’ signal. The power modulated fiber grating measurement system uses fiber Bragg gratings for strain sensing, and its power is modulated by long period fiber gratings to obtain the signals’ changes after stresses are applied. It has some advantages such as high reaction speed and resolutions with a simple setup. The main objective of this thesis is to establish a new power modulated fiber grating sensor system and make improvements on the accuracy of strain measurement. Another four measurement techniques, which include the laser Doppler vibrometer, the laser optical displacement sensor, strain gauges and the impedance analyzer, are used to verify the results obtained by fiber grating sensors. In addition to qualitative analysis, we also provide a method to make quantitative determination of dynamic displacements. To improve the practicability of the fiber grating sensing system, the wavelength division multiplexing system is also used in this study.
The experiments started with measurements on static systems and proceeded to steady systems. The highest frequency that the fiber grating sensing system can be achieved is about 160000 Hz. Finally, the transient responses of a beam, a plate and a solid block are investigated and are discussed in detail.

並列關鍵字

fiber ； power modulated ； fiber grating sensor

參考文獻

葉耀文，(2004)，短週期光纖光柵在動態系統的量測與應用，國立台灣大學機械工程研究所碩士論文

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Ball, G. A., and Morey, W. W., (1992) "Compression Tuned Single Frequency Bragg Grating Fiber Laser," Optics Letters, 17(6), 420-422

Berthold, A., and Dändliker, R., (1988) "Determination of the Individual Strain-Optic Coefficients in Single-Mode Optical Fibers," Journal of Lightwave Technology, 6(1), 17-20