| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam spot converting optical waveguide such that a manufacturing process is simple, manufacturing costs are reduced, and integral formation with an optical waveguide and manufacture on an optical device mounted substrate are enabled, and also to reduce the cost by improving optical coupling efficiency between optical parts, facilitating assembling/mounting and reducing manufacturing costs of an optical transmission module. SOLUTION: A beam spot enlarging optical waveguide 11 which enlarges the beam spot diameter is connected to a beam spot reducing optical waveguide 13 which reduces the beam spot diameter in the propagating direction of light beams, and a core layer is laminated with plural members having a different refractive index. Or the beam spot enlarging optical waveguide 11, a beam spot holding optical waveguide 12 which keeps the beam spot diameter almost constant and the beam spot reducing optical waveguide 13 are connected along the propagating direction of the optical beams, and the core layer is laminated with plural members having different refractive indexes. |
