本篇論文探討的是利用相敏光時域反射儀(Optical time domain reflectometer)作為光纖感測的的用途。起初要製作出一個窄線寬環形摻鉺光纖雷射，它的線寬為4KHz。實驗步驟是將窄線寬雷射發出的光源經過聲光調製器(Acousto-optic modulator)調製成脈衝寬度為200ns的脈衝光，再經過摻鉺光纖放大後打入6公里的傳感光纖。並且對237.5公尺的位置處、1750公尺處以及5825公尺處進行拍擊的模擬入侵。會讓傳感光纖中入侵點的三個位置有較劇烈的振盪波形。讓脈衝在傳感光纖中形成與未入侵時不同的背向雷利散射。最後再將有入侵的瑞利散射訊號傳送到採樣速率為8M/sec資料擷取卡擷取數據，再輸出到電腦。利用演算法將2000張瑞利散射的圖形做疊加形成2000張的疊圖，且利用移動平均法(Moving average method)以及相減法等方法做訊號處理。進而偵測到三個入侵位置的訊號。再與之後的改良方法做比較以及得出更好的訊噪比。

In this thesis, we research about the use of phase-sensitive optical time domain reflectometer as optical fiber sensing intrusion detection. Initially, a narrow-linewidth erbium-doped fiber laser with a linewidth of 1.8KHz was formed. In this experiment, we first modulate the laser light into a train of pulses with the pulse width of 200ns by using an acousto-optic modulator, and then amplify the pulse light with an erbium-doped fiber amplifier before the pulse light launched into a 6-kilometer sensing fiber. and into a 6-kilometer sensing fiber. And we slapped the sensing fiber at the positions of 237.5 meters, 1750 meters and 5825 meters. The three positions of the intrusion point in the sensing fiber will induce severe oscillation waveforms. Finally, the Rayleigh back-scattering signal is sent to a data acquisition card with a sampling rate of 8M/sec to capture the data, and then inputed to a computer analysis. Using program algorithms, 2000 Rayleigh back scattering graphics are superimposed to form 2000 stacked traces, and the moving average method and differential method are used for signal processing. In this study, we use a new method in which a trace is obtained by averaging first 100 traces and is used for the first trace. Also, we compensate the loss in the computation to raise the Signal-to-Noise Ratio(SNR), It can be found that the detection SNRs are improved , especially for intrusions occurring at far sites.

摘要 I
第一章 序論---- 1
1.1 光纖概論---- 1
1.2 研究背景---- 2
1.3 文獻回顧---- 3
1.3.1 光時域反射儀---- 3
1.3.2 相敏光時域反射儀---4
1.3.3 Sagnac干涉儀---- 6
1.4 研究動機---- 8
第二章 實驗原理----9
2.1 元件量測---- 9
2.2 雷射線寬---- 11
2.3 光的散射---- 12
2.4補償法---- 13
2.5 移動平均法及相減法----15
2.6 相減法之改良----17
第三章 實驗架構----18
3.1 雷射架構---- 18
3.2 相敏光時域反射儀架構----19
第四章 實驗結果與分析---- 21
4.1 光纖環形雷射架構---- 21
4.2 脈衝量測---- 24
4.3入侵模擬結果----25
第五章 結論與未來展望---- 53
5.1 結論---- 53
5.2 未來展望---- 54
參考文獻----55

[1] L. G. Cohen, P. Kaiser, and H. M. Presby,“Transmission characteristics of large-core, low-loss, single-mode fiber,”Optical Fiber Transmission OSA Technical Digest (Optical Publishing Group), 1975, paper TuD2
[2] Weiyu .Li, Weixin .Wang,”Investigation for waveguide and devices of integrated optics”,1988
[3] D. Gloge, "Optical fiber theory: Opportunities for advancement abound," Radio Science, vol. 12, no. 4, pp. 479-490, 1977.
[4] T. Okoshi, "Recent advances in coherent optical fiber communication systems," Journal of Lightwave Technology, vol. 5, no. 1, pp. 44-52, 1987
[5] C. Saravanos and R. S. Lowe, "Characterization techniques of single-mode fibers," Symposium on Antenna Technology and Applied Electromagnetics, pp. 1-6, 1988.
[6] G. P. Agrawal, Fiber-optic communication systems, John Wiley & Sons, 2012.
[7] X. Wang, Z. Yan, F. Wang, J. Hua, C. Mou, Z. Sun, X. Zhang, and L. Zhang, "An OTDR and gratings assisted multifunctional fiber sensing system," IEEE Sensors Journal, vol. 15, no. 8, pp. 4660-4666, 2015.
[8] H.-N. Li, D.-S. Li, and G.-B. Song, "Recent applications of fiber optic sensors to health monitoring in civil engineering," Engineering structures, vol. 26, no. 11, pp. 1647-1657, 2004
[9] S. S. Mahmoud, Y. Visagathilagar, and J. Katsifolis, "Real-time distributed fiber optic sensor for security systems: Performance, event classification and nuisance mitigation," Photonic sensors, vol. 2, no. 3, pp. 225-236, 2012
[10] Radim Sifta, Petr Munster, Petr Sysel, Tomas Horvath, Vit Novotny, Ondrej Krajsa and Miloslav Filka, "Distributed fiber-optic sensor for detection and localization of acoustic vibrations, " Metrology and Measurement Systems, vol. 22, no. 1, pp. 111–118, 2015.
[11] Q. Li, C. Zhang, L. Li, and X. Zhong, "Localization mechanisms and location methods of the disturbance sensor based on phase-sensitive OTDR, " Optik, vol. 125, issue 9, pp. 2099-2103, 2014.
[12] M. Mitra and S. Gopalakrishnan, "Guided wave based structural health monitoring: a review, " Smart Materials and Structures, vol. 25, no.5, pp.1-3, 2016.
[13] J. C. Juarez, E. W. Maier, C. Kyoo Nam, and H. F. Taylor, "Distributed fiber- optic intrusion sensor system," Journal of Lightwave Technology, vol. 23, no.6,pp. 2081-2087,2005.
[14] Zengguang Qin, Tao Zhu, Liang Chen, and Xiaoyi Bao ,”High Sensitivity Distributed Vibration Sensor Based on Polarization-Maintaining Configurations of Phase-OTDR”,IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 23, NO. 15, AUGUST 1, 2011
[15] P. R. Hoffman and M. G. Kuzyk, "Position determination of an acoustic burst along a Sagnac interferometer," Journal of Lightwave Technology, vol. 22, no. 2, pp. 494-498, 2004.
[16] Y. Shan, W. Ji, X. Dong, L. Cao, M. Zabihi, Q. Wang, Y. Zhang, and X. Zhang, "An enhanced distributed acoustic sensor based on UWFBG and self- heterodyne detection," Journal of Lightwave Technology, vol. 37, no. 11, pp. 2700-2705, 2019.
[17] Yuelan Lu, Tao Zhu, Member, IEEE, Liang Chen, and Xiaoyi Bao, “Distributed Vibration Sensor Based on Coherent Detection of Phase-OTDR”, IEEE JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 28, NO. 22, NOVEMBER 15, 2010
[18]Christopher S. Baldwin and Anthony J. Vizzini, "Acoustic emission
crack detection with FBG, "Society of Photo-Optical Instrumentation Engineers, vol. 5050, pp. 133–143, 2003
[19]H. Tsuda, J. H. Koo, and T. Kishi, "Detection of simulated acoustic emission with Michelson interferometic fiber-optic sensors,"Journal of Materials Science Letters, vol. 20, pp. 55–56, 2001.
[20]C. Franciscangelis, W. Margulis, L. Kjellberg, I.Soderquist, and F. Fruett, "Real-time distributed fiber microphone based on phase-OTDR," Opt Express, vol. 24, no. 26, pp. 29597-29602, Dec 26 2016.
[21] L.Yuelan,Z.Tao C.Liang,and B.Xiaoyi,"Distributed vibration sensor based on coherent detection of phase-OTDR," IEEE JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL28,NO.22,NOVEMBER 15,2010
[22] 許佳琪,王元慶, 徐楊睿, 梁琨, 鄭永超, 蘇云,張景豪.基于布里淵散射的海洋環境激光搖感技術研究進展[J].红外與激光工程,2021,50(6): 20211036. Jiaqi Xu, Yuanqing Wang, Yangrui Xu, Kun Liang, Yongchao Zheng, Yun Su, Jinghao Zhang. Research progress of ocean environmental laser remote sensing based on Brillouin scattering[J]. Infrared and Laser Engineering, 2021.