Shigeto TAGA,^1,3 Hiroaki TANAKA¹ and Yasuo KOKUBUN^1,2

¹Yokohama National University, Division of Electrical and Computer Engineering, 156, Tokiwadai, Hodogaya-ku, Yokohama, 240 Japan, ²also with Kanagawa Academy of Science and Technology, 3-2-1, Sakato, Takatsu-ku, Kawasaki, 213 Japan, ³Presently with Kanazawa Murata MFG. Co., Ltd., 18, Soyacho, Tsurugimachi, Ishikawa-gun, Ishikawa, 920-21 Japan

(Received May 28, 1996; Accepted September 5, 1996)

To eliminate the temperature dependence of narrow-band filter, a three-dimensional athermal waveguide of which optical path length is independent of temperature was developed at 1.3 μm wavelength. The temperature coefficient of the refractive index of films made of glass materials was measured at this wavelength, and a strip-loaded athermal waveguide was designed using a scalar finite element method. The temperature coefficient of optical path length was successfully decreased to 9.65×10^-9[/K] (0.1% of the conventional waveguide).

Key words : optical waveguide, narrow band optical filter, temperature coefficient of optical path length, athermal waveguide, temperature independent optical filter