| 摘要 |
PROBLEM TO BE SOLVED: To prevent the multiple reflection within an element and to improve S/N by inclining the flanks of groove parts for preventing stray light from the plane perpendicular to the front surface of the element. SOLUTION: This element is formed by laminating an optical waveguide layer 102 held by at least clad layers 101 therebetween on a substrate 100. The optical waveguide structure in the direction parallel with the lamination plane and perpendicular to an optical waveguide direction is a strip loading type structure or optical waveguide flush type structure. The positions exclusive of the waveguide parts guiding light are provided with the groove parts 105 for preventing the stray light of the depth penetrating the optical waveguide layer 102 or above. The flanks of the groove parts are inclined from the plane perpendicular to the element surface, where the angle formed by the element surface and the flanks of the groove parts is below 90 deg.. Of the light transmitted in an optical fiber 4, the stray light component failing to be coupled to the optical waveguides by a lens 103 arrives at the groove parts 105 after propagating in the slag waveguides. If the angle is below 90 deg., the stray light component is totally reflected to the front surface of the element by the flanks and is released to the outside of the element. |
