COUPLING/BRANCH FILTER FOR MULTIPLEX WAVELENGTH OPTICAL WAVE SYSTEM

PROBLEM TO BE SOLVED: To reduce optical switches, to delete signal processing of a bypass channel, to reduce the cost and to suppress deterioration of a characteristic by making a composite signal pass through a prescribed filter and bypassing signals except for the signal only when the channel is branched or substituted. SOLUTION: When an optical multiplex signal λ is received by a switch input 107, the optical multiplex signal λ is switched and is outputted to output 109 in response to a control signal 106 by local, remote, automatic and manual operations in a wavelength division/multiplex WDM filter/bypass device 100. It is inputted to a filter 104 through an optical link 111. The filter 104 branches a prescribed channel λ3, outputs the multiplex signal obtained by merging an input frequency channel λ3', inputs it to a switch 102 through an optical link 113, is switched and is outputted to 108. At the time of bypassing the filter, the control signal 106 outputs the received multiplex signal λ to 108 as it is with the switch 102 in a bypass state and an unnecessary processing is omitted.