Patent ID: 9654246
Date: 2017-05-16
CPC Classifications: H04J

Claim:
1. A system for communicating in a submarine transmission network, comprising: first, second, third and fourth bi-directional terminals; and a reconfigurable optical add/drop multiplexer (ROADM) unit coupled to the terminals, including: a first optical circulator coupled to the first terminal; a second optical circulator coupled to the second terminal; a third optical circulator coupled to the third terminal; a fourth optical circulator coupled to the fourth terminal; a first wavelength-selective switch (WSS), coupled to the first, second, and third optical circulators; a second WSS coupled to the first, second, and fourth optical circulators, wherein the first and second WSSes are bidirectional operated; a first 1:2 coupler positioned between the first circulator and the first and second WSSes; a second 1:2 coupler positioned between the second circulator and the first and second WSSes, wherein input signal from terminals are broadcast into two paths, one of which is an opposite terminal and sent through by one WSS for add/drop reconfiguration; a controller specifying symmetric wavelength assignments to the WSSes for simultaneous use in both directions; a power switched branching unit (PSBU) coupled to the ROADM unit; dummy lights used to balance total power, wherein the dummy lights are reused in the ROADM unit.