US 11,722,235 B2
Optical branch insertion device and optical branch insertion method
Hiroki Kawahara, Musashino (JP); and Takeshi Seki, Musashino (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 17/435,269
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Mar. 9, 2020, PCT No. PCT/JP2020/010115
§ 371(c)(1), (2) Date Aug. 31, 2021,
PCT Pub. No. WO2020/189386, PCT Pub. Date Sep. 24, 2020.
Claims priority of application No. 2019-052479 (JP), filed on Mar. 20, 2019.
Prior Publication US 2022/0149970 A1, May 12, 2022
Int. Cl. H04J 14/02 (2006.01)
CPC H04J 14/0212 (2013.01) 3 Claims
OG exemplary drawing
 
3. 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.