迴圈反射鏡式錐形光纖干涉儀感測器研究

The Study of Optical Sensor Sensitivity on Fiber Loop Mirror Setup and Tapered Fiber Structure

朱祐陞(Yu-Sheng Zhu)

指導教授 ： 許益誠

國立屏東科技大學/工學院/生物機電工程系所/碩士(2016年)

摘要

本研究利用光纖熔接機搭配拉伸機構，以放電加工搭配張力拉伸方法，在單模光纖上以單熔拉、半熔拉、多次熔燒等方式製作出三種不同的錐形光纖以做為感測元件，並分別結合光纖迴圈反射鏡(Fiber Loop Mirror)基本型、基本型上加裝偏振持光纖以及雙環反射鏡架構，形成三種光纖迴圈反射鏡干涉儀感測器，探討三種製程製作之錐形光纖在不同架構上頻譜圖及對折射率量測的感測靈敏度之影響。
　　在基本光纖迴圈反射鏡量測架構下，實驗上僅有在半熔拉製程觀察出較規律之頻譜訊號，折射率量測範圍1.333到1.337中在擬定錐腰直徑30μm可得到最佳靈敏度為-152.5nm/RIU，而此架構下也可觀察到頻譜有波包飄移現象，經由波包分析可得到在半熔拉製程錐腰直徑44μm可得最佳靈敏度為-5530nm/RIU，而在附加偏振保持光纖迴圈反射鏡架構下，可將自由光譜範圍從1~2nm提升至5~6nm，使得光纖頻譜較容易觀察，在半熔拉製程擬定錐腰直徑40μm時量測到規律的頻譜，其最佳感測靈敏度為-67.5nm/RIU，雙環光纖迴圈反射鏡式架構，利用濾波迴圈提供給感測迴圈訊號，使得頻譜訊號較為穩定，在飄移量的部分略小於其他兩個量測架構，提高了判定係數，可以得到在單次熔拉製程錐腰直徑40μm時，有最佳的感測靈敏度為-77.5 nm/RIU。

關鍵字

光纖感測器 ； 光纖迴圈反射鏡 ； 干涉儀 ； 錐形光纖

並列摘要

The effect of tapered fiber with different fabricating process on the fiber loop mirror interferometer sensor is demonstrated. The taper structure is fabricated on a standard single-mode fiber by fusion splicer with designed stretching mechanism. The fabrication process is done in three different ways: single fusion-stretching (SFS), multiple fusions with single stretching (MFSS) and multiple fusions (MF). Measurement configurations of the fiber loop mirror interferometer (FLMI) sensor were divided three different ways, Fundamental, Fundamental with Polarization Maintaining Fiber (FPMF) and Cascade. In order to obtain the effect of different taper types and three measurement configurations on the sensitivity of FLMI sensor, the tapers in FLMI sensor are achieved by SFS, MFSS and MF process for refractive index (RI).
The result shows that the best RI sensing sensitivity of the FLMI sensor is -152.5nm/RIU with taper fiber fabricated by MFSS process and the taper waist of 30μm in the Fundamental measurement configuration of FLMI for the RI range of 1.333-1337. The spectrum shift analysis of global wavelength envelope indicates that the best sensing sensitivity of -5530nm/RIU is occurred in the FLMI sensor with taper waist of 40μm fabricated by MFSS process. The free spectrum range of spectrum are increased by 1-2nm to 5-6nm in the FPMF measurement configuration of FLMI sensor, so the dip of the spectrum will be obviously.，The best RI sensing sensitivity of the FLMI sensor is -67.5nm/RIU with taper fiber fabricated by MFSS process and the taper waist of 40μm in the FPMF configuration of FLMI for the RI range of 1.333-1341.The spectrum of the Cascade measurement configuration is more stable than others, cause of Filter loop avoiding the noise and offering the cleaning signal to Sensor loop. The best RI sensing sensitivity of the FLMI sensor is -77.5nm/RIU with taper fiber fabricated by SFS process and the taper waist of 40μm in the Cascade configuration of FLMI for the RI range of 1.333-1341.

並列關鍵字

Optical fiber sensor ； Fiber loop mirror ； Interferometer ； Fiber taper

參考文獻

[28] 方世榮，2008，基礎統計學，華泰文化事業股份有限公司，第449-467頁。

[17] 蔡武通，2010，D型光纖研磨技術之研究，碩士論文，國立虎尾科技大學，光電與材料科技研究所。

[5] Zhen, S. L., Cheng, X. Y., Chen, J., Zhou, M., Liu, F., Yu, J. L., & Yu, B. L. 2014, “Hybrid configuration of Sagnac and modal interferometer with high extinction ratio,” Optik-International Journal for Light and Electron Optics, Vol. 125, Issue 3, pp. 1275-1277.

[2] Zibaii, M. I., Frazão, O., Latifi, H., & Jorge, P. A. S. 2011, “Controlling the sensitivity of refractive index measurement using a tapered fiber loop mirror,” Photonics Technology Letters, IEEE, Vol. 23,Issue 17,pp. 1219-1221.

[3] Zhong, C., Shen, C., You, Y., Chu, J., Zou, X., Dong, X., ... & Wang, J. 2012, “A polarization-maintaining fiber loop mirror based sensor for liquid refractive index absolute measurement,” Sensors and Actuators B: Chemical, Vol. 168, pp. 360-364.