Hirohisa YOKOTA, Eiichi SUGAI and Yutaka SASAKI

Department of Systems Engineering, Faculty of Engineering, Ibaraki University, 4-12-1 Nakanarusawa-cho, Hitachi-shi, Ibaraki, 316 Japan

(Received July 1, 1996; Accepted September 9, 1996)

An optical irradiation method for high-speed fiber coupler fabrications without contamination is proposed. In optical fiber taper fabrications we found an interesting effect that fiber elongation is self-arrested although laser irradiation is continued. This is a typical effect in the optical irradiation method, but is not seen in the flame method or the thermal heating method. The gself-controlled fiber taper shape effecth is theoretically explained by considering thermal energy flows, and optical fiber couplers are fabricated using this effect. From our experiments, we show that optical fiber coupler fabrications at high-speed without contamination are possible using the optical irradiation method.

Key words : optical fiber coupler, optical fiber taper, CO₂ laser, optical fiber devices, thermal energy flow analysis