Using a surface relief D-Fiber Bragg grating to Monitor volatile organic compounds

• Main Authors: Guo-Ting Chen, 陳國庭
• Other Authors: Feng-Tzai Weng
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/r523q3

碩士 === 國立虎尾科技大學 === 機械與機電工程研究所 === 99 === In this paper, we proposed a method to fabricate an D-shaped fiber of surface-relief Bragg grating filter by utilizing D-shaped fiber polishing along with photolithography and holographic interference lithography technologies. A fiber-optic chemical sensor based on a surface relief fiber Bragg grating (SR-FBG) fabricated with elliptical core D-shaped optical fiber (D-fiber) was also fabricated to detect volatile organic compounds. In conclusion, we have successfully created a process to fabricate the grating on the D-shape fiber. A good aspect ratio on the grating pattern could be obtained. By polishing process, the surface of the fiber could be near the core. It will allow the overlap between the grating and the field of the guided modes to increase. A fiber-optic chemical sensor based on a surface relief fiber Bragg grating (SR-FBG) on a D-shaped optical fiber (D-fiber) was also fabricated. A PDMS layer is spun on top of the surface relief grating to absorb the analyze chemical. The refractive index of the PDMS changes as the chemical of interest is absorbed into this layer and the Bragg wavelength shifts. A linear relationship between the chemical concentration and the wavelength shift is found.