| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical waveguide in which insertion loss caused when light enters an array waveguide from a slab waveguide or enters the slab waveguide from the array waveguide may be reduced without increasing a circuit scale and without complicating circuit design and fabrication. <P>SOLUTION: An optical waveguide comprises: a slab waveguide 1 including a diffraction grating GP or GA; an array waveguide 2 connected to a portion of the diffraction grating GP or GA where a bright interference part of a self image of the grating is formed; and a refractive index changing region DV formed between the slab waveguide 1 and the array waveguide 2 in which an average refractive index in a refractive index distribution along a direction substantially vertical to a light propagation direction is increased on average from a side of the slab waveguide 1 toward a side of the array waveguide 2 and an average refractive index in a refractive index distribution along a direction substantially parallel to the light propagation direction is large on a central axis of the array waveguide 2. <P>COPYRIGHT: (C)2012,JPO&INPIT |
