| 摘要 |
This optical waveguide has: a core layer provided with a core section and side-surface cladding sections that abut both side surfaces of the core section; and cladding layers that are layered on each of the two surfaces of the core layer. The refractive index distribution (W) in the direction of the width of the core layer has two local minima, one first local maximum, and two second local maxima that are smaller than the first local maximum, and has a region wherein these are arranged in the following order: a second local maximum, a local minimum, the first local maximum, a local minimum, and a second local maximum. The refractive index varies continuously across the entire refractive index distribution. Meanwhile, the refractive index distribution (T) in the direction of thickness of the optical waveguide has: a third local maximum; a first section wherein the refractive index continuously declines from the position of the third local maximum towards the cladding layers; and a second section that is positioned more towards the two side surfaces of the optical waveguide than the first section is, and wherein the refractive index is virtually fixed. |
