A Nonequal- and Common-path Interferometer and Its Application

• Main Authors: Cheng-Chung Chang, 張政中
• Other Authors: Shyh-Tsong Lin
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/83bfw6

碩士 === 國立臺北科技大學 === 光電工程系研究所 === 95 === This thesis proposes a novel interferometer for determining wavelength shift. It is a nonequal- and common-path interferometer, and it uses a rotating analyzer to generate AC signals so the phase corresponding to the wavelength shift can be extracted. A nonequal- and common-path interferometer is a high sensitivity and high stability one, the use of the rotating analyzer simplifies the setup of the interferometer. The principle of the proposed interferometer is introduced. A setup constructed to calibrate this interferometer was developed. The experimental result shows that the interferometer had a sensitivity of 269.67 degree/nm. Besides, the setup was also adopted for testing the stability of the proposed interferometer, the result shows that it was 3×10-4 nm. To verify the applicability of the interferometer, it was adopted to determine the wavelength shift of the wave reflected from a fiber Bragg grating bonded on a loaded four-point bending beam. A transformation from the wavelength shift to beam strain was done and it was finally compared with theoretical strain and strain gauge. The comparison agrees the applicability of the interferometer.