Abstract

Based on the results of the coupling process in a multimode biconical fiber coupler,¹ we have analyzed Its temperature dependence. We find that there are two cases which are dependent on both the geometry of the fiber and the material parameters. One is the temperature-sensitive area where the coupling efficiency of the coupler is very sensitive to the temperature, another is the temperature-nonsensitive area where the coupling efficiency of the coupler is almost independent of the temperature. So it is possible, in theory, to design fiber-optical temperature sensors as well as temperature-independent couplers, with a wide range of characteristics, by controlling the geometry of the fiber and also the material parameters such as refractive indices and temperature coefficients of refractive indices.

© 1985 Optical Society of America