Abstract: Disclosed is a method of fabricating an optical fiber or an optical device doped with reduced metal ion and/or rare earth ion, comprising steps of: forming a partially-sintered fine structure in a base material for fabricating the optical fiber or the optical device; soaking the fine structure into a doping solution containing a reducing agent together with metal ion and rare earth ion during a selected time; drying the fine structure in which the metal ion and/or rare ion are/is soaked; and heating the fine structure such that the fine structure is sintered.

Abstract: Disclosed herein is an apparatus for measuring the differential mode delay of multimode optical fiber. The apparatus includes a tunable laser source, an interferometer, a data collecting device, and a computer. The tunable laser source outputs light, frequencies of which vary linearly. The interferometer generates multimode light and single mode light by separating light, which is output from the tunable laser source, transmitting the multimode light and the single mode light to the multimode optical fiber, which is a measurement target, and a single mode path, which is a reference, and generating a beating signal by causing the multimode light and the single mode light to interfere with each other. The data collecting device collects the beating signal from the interferometer. The computer converts the frequency components of the beating signal into components in a time domain, and calculating the mode delay of the multimode light.

Abstract: Disclosed is a method of fabricating an optical fiber or an optical device doped with d metal ion and/or rare earth ion, comprising steps of: forming a partially-sintered fine re in a base material for fabricating the optical fiber or the optical device; soaking the fine re into a doping solution containing a reducing agent together with metal ion and rare on during a selected time; drying the fine structure in which the metal ion and/or rare ion soaked; and heating the fine structure such that the fine structure is sintered.

Abstract: Disclosed is a method of fabricating an optical fiber or an optical device doped with reduced metal ion and/or rare earth ion, comprising steps of: forming a partially-sintered fine structure in a base material for fabricating the optical fiber or the optical device; soaking the fine structure into a doping solution containing a reducing agent together with metal ion and rare earth ion during a selected time; drying the fine structure in which the metal ion and/or rare ion are/is soaked; and heating the fine structure such that the fine structure is sintered.