Wavelength division multiplex branching unit and method of operation for optical transmission systems

摘要

A wavelength division multiplex branching unit for an optical fibre transmission network comprises a branching unit housing (100) and means (102) external to the housing for permitting the connection of one or more wavelength selective devices (A, B, C, D) to a trunk transmission fibre. The wavelength selective devices are each responsive to a different transmission wavelength and are effective to direct transmission signals have that response wavelength from the trunk fibre to a spur fibre of the branch cable.