METHOD FOR FORMING GRATING IN OPTICAL FIBER AND VARIABLE ATTENUATION OPTICAL FIBER GRATING FILTER OBTAINED BY THE METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for easily varying the attenuation quantity of a long-period FG element and to actualize the concrete constitution of the small-sized, convenient long-period FG element. SOLUTION: A distribution area of cyclic temperature variation is formed in a core of an optical fiber by using a microheater and a periodic refractive index distribution is formed by temperature characteristics of the refractive index of the core of the optical fiber to provide a grating structure, and the temperature having the cyclic temperature variation is varied to form gratings in the optical fiber. A variable attenuation optical fiber grating filter is actualized by this method.