| 摘要 |
PROBLEM TO BE SOLVED: To fully secure an optical waveguide primarily in a low-order mode by having a core refractive index distribution in which a core refractive index gradually lowers towards the outside of bending, in the bending part of a multi- mode optical waveguide, and thereby maintaining a profile in which an outgoing light beam is almost unchanged from an incident light beam even in the occurrence of strong bending. SOLUTION: In the bending part of a bending optical waveguide 4 as a multi-mode optical waveguide, the refractive index n(r) at the core part 5 is set such that it gradually lowers towards the outside of the bending in the core refractive index distribution. Desirably, the core refractive index n (r) at the bending part is designed to lower gradually towards the outside of the bending under a setting condition of n (r)=nrefexp -(r-r0)/r0}, assuming that nref is the core reflactive index as a reference and that r0 is the coordinate in the optical waveguide center at the bending part. Further, the core refractive index n (r) at the bending part may be designed to lower gradually in steps towards the outside of the bending. |
