Patent ID: 9201196
Filing Date: 2015-12-01
Classification: G02B

Abstract:
1. A high-order mode filter, comprising: a planar slab region; a band-shaped projection which is formed on the slab region in an optical waveguide direction; a first optical waveguide including a disturbance element, which is formed at a position distanced from the projection in the slab region, with a lower refractive index than the slab region adjoined in a planar direction; and a second optical waveguide in which the disturbance element not formed close to the projection, wherein both the first optical waveguide and the second optical waveguide are alternately arranged at least one or more times, wherein a phase relationship between a removable high-order mode and an intentional high-order mode which is higher than the removable high-order mode and which has a same symmetry as the removable high-order mode is fixed at a connecting face between the first optical waveguide and the second optical waveguide, and wherein lengths of the first optical waveguide and the second optical waveguide in the optical waveguide direction are defined to cause a large high-order mode loss due to interference between the removable high-order mode and the intentional high-order mode, wherein, based on a wavelength λ of light in a vacuum, an effective refractive index n (where m denotes an integer equal to or higher than 1) and