Optical branch insertion device and optical branch insertion method

An optical add/drop multiplexing device comprising:

• branch function units, including one or more processors, connected to each of WSSs connected to respective routes, each route i) having a plurality of optical fibers and ii) dropping a subset of optical signals having different wavelengths included in original optical signals having a plurality of wavelengths and being transmitted through the optical fibers by wavelength division multiplexing, wherein the dropped subset of optical signals includes M-D signals, where M is the number of output ports of each WSS, and D is the number of optical paths between the input WSS and the output WSS, wherein an output port for drop is additionally installed for each of the WSSs resulting in that each WSS has a total of M+1 output ports;
• CD/CDC function units, including one or more processors, configured to transmit the dropped subset of optical signals that is branched by the branch function units to a plurality of transponders;
• a bypass unit, including one or more processors, is configured to be connected between the output port additionally installed and input ports of the CD/CDC function unit and transmit the optical signal by each of the WSSs to the CD/CDC function unit;
• and
• selectors each connected between i) a set of K WSSs each having 1 input port and M output ports, K being a number of 2 or more indicating the number of input ports of each selector, and ii) one of the branch function units, the number of selectors being equal to or greater than a positive integer obtained by dividing a numerical value D(M-D) by K, the numerical value D(M-D) being obtained by multiplying the number (M-D) of optical signals dropped by each of the WSSs by the number D, wherein
• the selector is configured to select any one of the optical signals dropped by the set of WSSs and output the selected optical signal to the branch function unit, and when one selector of the selectors selects a first optical signal dropped by one of the set of WSSs, the other selector selects a second optical signal dropped by another WSS.

An optical add/drop multiplexing method of an optical add/drop multiplexing device including:

• branch function units connected to each of WSSs connected to respective routes, each route i) having a plurality of optical fibers and ii) dropping a subset of optical signals having different wavelengths included in original optical signals having a plurality of wavelengths and being transmitted through the optical fibers by wavelength division multiplexing, wherein the dropped subset of optical signals includes M-D signals, where M is the number of output ports of each WSS, and D is the number of optical paths between the input WSS and the output WSS, wherein an output port for drop is additionally installed for each of the WSSs resulting in that each WSS has a total of M+1 output ports,
• CD/CDC function units configured to transmit the dropped subset of optical signals that is branched by the branch function units to a plurality of transponders,
• a bypass unit configured to be connected between the output port additionally installed and input ports of the CD/CDC function unit and transmit the optical signal by each of the WSSs to the CD/CDC function unit, and
• optical couplers each connected between i) a set of K WSSs each having 1 input port and M output ports, K being a number of 2 or more indicating the number of input ports of each optical coupler, and ii) one of the branch function units, the number of optical couplers being equal to or greater than a positive integer obtained by dividing a numerical value D(M-D) by K, the numerical value D(M-D) being obtained by multiplying the number (M-D) of optical signals dropped by each of the WSSs by the number D,
• the optical coupler executing:
• coupling the subset of optical signals of different wavelengths dropped by the set of WSSs connected to the optical coupler into one coupled optical signal and outputting the coupled one optical signal to the branch function unit.