| 摘要 |
PROBLEM TO BE SOLVED: To improve signal reception sensitivity (i.e., to speed up the transmission rate), and to increase the scale of an optical switch, by removing the branching loss in the combiner part of the optical switch formed by using a semiconductor optical amplifier, splitter and combiner. SOLUTION: This optical coupler has a substrate 1, on which optical waveguides are formed, multimode fibers 4 optically coupled to these optical waveguides, and plural single mode fibers 5 optically coupled to these optical waveguides. The optical waveguides formed on the substrate 1 include the multimode waveguide 3 and the plural single mode waveguides 2. The multimode waveguide 3 is optically coupled to the multimode optical fibers 4 and the single mode waveguide 2 are optically coupled to the single mode fibers 5. As a result, the generation of the branching loss is suppressed. |
