Patent ID: 6999653

Claim:
A 4-port wavelength selective router comprising four ports ( 1 , 2 , 3 , 4 ) with internal signal transmission paths between three port pairs (( 1 , 2 ), ( 2 , 3 ), ( 3 , 4 )), and wherein; when the first optical signal group, Group A, consisting of one or more signals with different wavelengths, and the second optical signal group, Group B, consisting of one or more signals with different wavelengths excluding signals in Group A, propagate bidirectionally, at port ( 2 ) Group A signals are inputted and Group B signals are outputted; at port ( 3 ) Group B signals are inputted and Group A signals are outputted; between port ( 2 ) and ( 3 ) only Group A signals are transmitted from port ( 2 ) to port ( 3 ), and no signals can be transmitted in the other direction; between port ( 1 ) and ( 2 ), and port ( 3 ) and ( 4 ) the Group B signals or both Group A and B signals can be transmitted, but both Group A and B signals are not transmitted simultaneously through the two port pairs (in other words, between port ( 1 ) and ( 2 ), and port ( 3 ) and ( 4 ) at least one port pair transmits only the Group B signals); between port ( 1 ) and ( 2 ), and port ( 3 ) and ( 4 ) optical waves can be transmitted bidirectionally, but at least one port pair transmits the signals in one direction, from port ( 1 ) to ( 2 ) or from port ( 3 ) to ( 4 ); and signals inputted to a specific port ( 1 , 2 , 3 , 4 ) cannot be transmitted to more than one port ( 1 , 2 , 3 , 4 ) simultaneously.