Possesses high null distribution the guided wave path fiber

摘要

PROBLEM TO BE SOLVED: To make it possible to exhibit a higher cut-off frequency than improvement of bending resistance and to impart low total dispersion in an expanded wavelength window by forming a waveguide fiber of a core region consisting of three regions and a clad layer enclosing these core regions, respectively providing the region and the layer with specific refractive index distributions and forming the core regions having inside and outside distribution volumes, etc., of a range of specific values. ;SOLUTION: This waveguide fiber has the core consisting of the three regions; the central region disposed with respect to the asymmetrical axis of the waveguide, the first adjacent region in contact with the central region and the second adjacent region in contact with the first adjacent region. The clad layer encloses the second adjacent region. When the refractive index distributions of the respective regions are compared, the central region (distributions 2, 4, etc.), and the second adjacent region (distributions 12, 14) have the refractive index relatively higher than the first adjacent region (distribution 10) and the clad layer (distribution 24). The waveguide has the inside distribution volume of the range of 2.90 to 3.90 and the outside distribution volume of the range of 7.20 to 10.20 and the ratio of the outside/inside distribution volumes is in a range of 1.96 to 3.04.;COPYRIGHT: (C)1999,JPO