Tsutomu ICHIMURA,¹ Naoki ANNDO,^1,3 Tadayuki FUNABA,¹ Shigeru ENDO,¹ Yoshiki ODAGIRI,^1,4 Naohiro TAN-NO¹ and Humio INABA²

¹Department of Electronics and Information Engineering, Yamagata University, Yonezawa, 992 Japan, ²Department of Electronics, Tohoku Institute of Technology, 35-1 Yagiyama-kasumichou, Taihaku-ku, Sendai, 982 Japan and Biophotonics Information Laboratories, 683 Kurumanomae, Ohaza Numagi, Yamagata, 990 Japan

(Received June 6, 1995; Accepted November 7, 1995)

We propose and confirm a novel technique of optical frequency domain reflectometry based on multidigitized coherence using a multimode laser. The proposed system can easily provide the potential for high resolution on the order of 10 μm without scanning frequencies as in frequency domain reflectometers of either continuous or stepwise sweep. The theoretical approach agrees well with the experimental results demonstrated using a commercially available multimode laser diode.

Key words : optical frequency domain reflectometer, multi mode laser, optical signal processing, optical interference measurements, laser coherence