Patent ID: 7110673
Filing Date: 2006-09-19
Classification: H04J

Abstract:
1. A node in an optical communication network, said node being connected in a transmission path for carrying multiple traffic data channels including wavelength division multiplexed channels carried in a first wavelength band and at least one service channel associated with said wavelength division multiplexed channels and carried on at least one further wavelength separate from said first wavelength band, said node including a set of first filter elements for adding at least one of said wavelength division multiplexed data channel wavelengths to said transmission path and dropping at least one of said wavelength division multiplexed channel wavelengths from said transmission path, an extraction element for dropping said at least one service channel wavelength from said transmission path, said extraction element being arranged upstream of said first set of filter elements, a splitting means arranged to receive optical signals from said extraction element and to separate said service channel wavelength from at least one second wavelength band, wherein said splitting means are connected to said coupling means via a bypass path for relaying signals carried on said at least one second wavelength band from said splitting means to said coupling means, and a combining element for adding said at least one service channel wavelength to said transmission path, said combining element being arranged downstream of said set of first set of filter elements, wherein said extraction and combining elements are adapted to drop and add, respectively, said at least one second wavelength band in addition to said at least one service channel wavelength, and passively relay said first wavelength band, said at least one second wavelength band being separate from said first wavelength band and carrying at least one optical traffic data channel.