光纖雷射感測器之研究

Abstract

本論文提出一新型之光纖雷射感測器，並對最為可行之線性及環狀光纖雷 射感測器結構作詳盡的理論分析。本論文所述之光纖雷射感測器，主要是 為了量測材料或建物受拉力、壓力或變位之大小而設計。利用參鉺光纖做 為活性介質，吸收輸入光源之能量，再激發出光子，雷射將在符合共振條 件且增益最大的頻率振盪。所輸出之雷射頻率，會因共振及增益條件改變 而變化，而光纖隨待測物體受力應變而應變時，即會改變共振及增益條件 ，因此可由輸初雷射頻率之變化，量測待測物體受力應變之大小。若能再 利用一轉換器將其他物理量之改變轉換為作用在光纖上之拉、壓力，則我 們所探討的光纖雷射感測器也可用來量測其他的物理量。 In the thesis we propose a new type of fiber laser sensors nd perform theoretical analyses for both linear and ring laserructures. The fiber laser sensors discussed in the thesis are mainlyor measureing the stress, pressure, or strain of materials. The sensor itself is a Er-doped CW fiber laser. A laser oscillates at the frequency that satisfies the resonance condition and that has maximum gain(minimum loss). When some portion of the fiber in the cavity is under a stress or a pressure, the spectral distribution of cavity loss is changed due to birefringent filtering. Thiseads to a change of the lasing frequency. By measuring theange of the lasing frequency, one can decide the magnitudes ofstress or pressure applied on the fiber. With a transducercan transduce the change of another physical quantity intohange of the stress or pressure applied on the fiber, the fiber laser sensors also can be usded to measuring other physical quantities.