OPTICAL BRANCH INSERTION DEVICE AND OPTICAL TRANSMISSION SYSTEM USING OPTICAL BRANCH INSERTION DEVICE

Device cost and electric power consumption are reduced. Nodes 11a to 11d as optical add/drop multiplexers each include AWGs 24a and 24b connected between light transmission paths as optical fibers 12 and 13 and transponders 25a to 25n and configured to output optical signals from the light transmission paths to the transponders 25a to 25n through ports and transmit optical signals from the transponders 25a to 25n to the light transmission paths through ports, and an optical coupler 24c configured to connect ports of the AWGs 24a and 24b to the transponders 25a to 25n through coupling or bifurcation. The channel interval of ports of the AWGs 24a and 24b is multiple times larger than the channel interval of ports of the transponders 25a to 25n, and transponder signals of a plurality of different wavelengths to and from one or a plurality of the transponders 25a to 25n can pass through ports of the AWGs 24a and 24b.