| 摘要 |
PROBLEM TO BE SOLVED: To provide a fiber optic sensor which can prevent the false detection of an external force such as a vibration and an impact. SOLUTION: The fiber optic sensor 1 includes a light source 11, an optical fiber 15 laid through a measurement area 12, an optical detector 14, and an analyzer 16. A measuring optical fiber 10 within the measurement area 12 includes two first measuring optical fibers 20, 21 of a Mach-Zehnder interferometer (MZI) 19 and a second measuring optical fiber 22 for polarization fluctuations detection. An optical wave entering the optical detector 14 includes an interference wave with its intensity changed caused by a change in the interference at a second coupler 18 of the MZI 19 through a sensitive reaction to an external force and a polarization fluctuating wave with intensity responsive to polarization fluctuations by the external force. Since an external force such as a vibration and an impact is detected through the combination of the MZI 19 which receives an external force such as a vibration and reacts to it sensitively to generate an interference wave and the second measuring optical fiber 22 which receives the external force and reacts to it insensitively to generate a polarization fluctuating wave, the false detection of an external force such as a vibration and an impact can be prevented. COPYRIGHT: (C)2010,JPO&INPIT |
