| 摘要 |
PURPOSE:To obtain a high extinction ratio by loading a metallic thin film on the path surface of one of two branch-side optical waveguides which are made of semiconductor materials and have p-n junction structures and using the metallic thin film as a reverse voltage applying means for the p-n junction structures. CONSTITUTION:The whole optical waveguide consists of a main optical waveguide C and the branch-side optical waveguides A and B which branch from the main optical waveguide C. Further, n<-> clad layers 16a and 16b and cap layers 17a and 17b made of n<+>GaAs are formed in order on core layers 15a and 15b formed on an n<-> clad layer 14 in a ridge shape and the p-n junction structures are formed between the cap layers 17a and 17b, and n<-> clad layers 16a and 16b. Then an insulating film 18 on the path surface of the branch-side optical waveguide A is partially removed to form a window 19 which extend in the path length direction, and the metallic thin film 20 is loaded in contact with the cap layer 17a and serves as the reverse voltage applying means for the p-n junction structures. Consequently, the high extinction ratio is obtained. |
