Takeaki YOSHIMURA, Nobuaki KOHINATA and Jiro MORITA

Department of Computer and Systems Engineering, Faculty of Engineering, Kobe University, Rokko, Nada, Kobe, 657 Japan

(Received October 16, 1995; Accepted January 24, 1996)

The signal quality of a fiber-optic distributed temperature sensor based on optical time domain reflectometry (OTDR) is improved using a pre-filtering technique in the iterative deconvolution method. Investigation of the performance is proposed using iteration conditions in which recovery rate of the signal-component is equal to that of the unfiltering technique. The recovered signal in the pre-filtering technique gives a good signal-to-noise ratio (SNR), 3 times of the unfiltered signal. Consequently, improvements in the OTDR signal with SNR of from 10 to 100 are obtained under the iterations for both distance and temperature resolutions.

Key words : iterative method, pre-filtering, fiber sensor, OTDR signal