| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical fiber in which both of a single mode operation and a large effective cross section are easily achieved. <P>SOLUTION: A photonic bandgap fiber (PBGF) 1B is an optical fiber which includes: a core region 10; a clad region 20B surrounding the core region 10; and a jacket region 30 surrounding the clad region 20B. The optical fiber has a refractive index distribution which is constant along the fiber axis. The clad region 20B has a two-dimensional periodic structure in which high refractive index regions 21 are arranged in triangle lattice in a low refractive index back ground region 22 in the cross section perpendicular to the fiber axis. The core region 10 is formed of a defect of seven lattice points of a two-dimensional periodic structure at the central part of the cross section. The clad region 20B includes a belt-shaped periodic-structured defective region 23 in which the high refractive index regions are continuously removed along the radial direction in the cross section. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
