| 摘要 |
PROBLEM TO BE SOLVED: To emit a beam in the vertical direction to the end surface of a substrate by varying tilt angles of two mutually facing sides of a ridge waveguide on the substrate, and proving selectively an energization easy layer on the top face of the ridge waveguide. SOLUTION: Tilting of left and right sides of a ridge waveguide 8 is asymmetrical due to formation on a tilt substrate. An energization easy layer 7 is formed selectively corresponding to the asymmetry of the ridge. That is, the left side of the ridge waveguide 8 is removed in order to allow the electric current injected via the energization easy layer 7 to spread at left and right of the ridge. In this case, the layer 7 is preferably provided so that a distance (a) from one end of the foot of the ridge and a distance (b) from the other end may be almost equal. Consequently the electrical current flows evenly left and right in the vicinity of the central part of the ridge waveguide 8. Therefore, the gain becomes symmetry left and right, and the spread of the optical mode becomes also symmetry. As a insult, beam is emitted vertically from the end face.
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