A method for measuring a distributed external pressure field along an optic fiber is discussed, which is based on the principle of mode-coupling of polarization-maintaining fiber and optical path compensation in the interference of two beams from a broadband light source. A modified Mach-Zehnder interferometer is used to process the optical signal representing the distributed pressure information, and a polarization light heterodyne detecting technique is used to improve the signal-to-noise ratio and to eliminate the influences of light source fluctuation and background light. For the automatic measurement of the distributed pressure information, an A/D and interface circuit is designed. Under the control of the microcomputer, the arm of the interferometer with an optical path scanning setup scans a distance corresponding to the length of the fiber, then the information of the pressure field is obtained. The experimental results have shown that the measuring system has a high measurement accuracy and a rather large pressure measuring range (10 g/mm - 500 g/mm).

Date Published: 11 May 1993
PDF: 8 pages
Proc. SPIE 1979, 1992 International Conference on Lasers and Optoelectronics, (11 May 1993);

Published in SPIE Proceedings Vol. 1979:
1992 International Conference on Lasers and Optoelectronics
Sui-Sheng Mei; Bingkun Zhou, Editor(s)