| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a low dispersion optical fiber compatible with both lowering of wavelength dispersion and expansion of an effective core cross-sectional area in use wavelength range. <P>SOLUTION: The outer circumferential side of a center core 1 is covered with a 1st side core 2; the outer circumferential side of the 1st side core 2 is covered with a 2nd side core 3; the outer circumferential side of the 2nd side core 3 is covered with a clad 5; and when the maximum refractive index of the center core 1 is expressed by n1, the minimum refractive index of the 1st side core 2 by n2, the maximum refractive index of the 2nd side core 3 by n3, and the refractive index of the clad 5 by nc, a relation of n1>n3>nc>n2 is made to be satisfied. The concentration distribution of the additive that raises the refractive index of SiO<SB>2</SB>doped in the 2nd side core has the maximum part in the radial direction of the optical fiber, wherein the maximum part is made to be situated to the 1st side core from the center in the radial direction of the 2nd side core. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
