Optical device for rearranging wavelength channels

An optical network comprising first and second optical network nodes, each node comprising an optical device for rearranging wavelength channels, each optical device comprising:

• a wavelength selective coupler having an input port and first and second output ports, for separating wavelength channels received at the input port into first and second groups of wavelength channels for output at the first and the second output ports, respectively;
• an optical grating demultiplexor having first and second input ports optically coupled to the first and the second output ports of the wavelength selective coupler, respectively, and a plurality of output ports, for demultiplexing the first and the second groups of wavelength channels;
• wherein the first and the second input ports of the optical grating demultiplexor are offset from each other so as to couple a wavelength channel of the first group from the first input port, together with a wavelength channel of the second group from the second input port, into a same output port of the optical grating demultiplexor,
• a plurality of wavelength selective splitters, wherein each one of the plurality of wavelength selective splitters is optically coupled to one of the plurality of the output ports of the optical grating demultiplexor, for separating wavelength channels of the first group from wavelength channels of the second group;
• wherein the first group includes transmission channels and the second group includes reception channels,
• wherein the first and the second wavelength selective splitters include duplex filters for separating the transmission channels from the reception channels;
• wherein each of the first and second nodes further comprises
• a plurality of receivers each coupled to a particular one of the duplex filters for receiving one of the reception channels;
• and
• a plurality of transmitters each coupled to a particular one of the duplex filters for transmitting one of the transmission channels;
• wherein the optical network further comprises an optical transmission line that couples together the input ports of the wavelength selective couplers of the first and the second optical network nodes, and
• wherein the transmission channels of the first optical network node are the reception channels of the second optical network node, and the reception channels of the first optical network node are the transmission channels of the second optical network node.