| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical add-drop multiplexer(ADM) which avoids crossing of waveguides by having Mach-Zehnder interferometer constitution having demultiplexer/multiplexer couples at respective shunts. SOLUTION: In ADM 60, the respective multiplexer/demultiplexer couples (300-1, 400-1) (300-2, 400-2) are interconnected by coherent connection waveguides 70 and 80 having heating elements 65 and 66 for increasing the path length of a selected connection waveguide. Waveguide optical couplers 61 and having an asymmetrical transfer function are used for the input port and output port of the ADM 60. Those couplers add and drop selected optical channels for an optical transmission line by cooperating with heating elements in active states. |
