SUBMARINE CABLE BRANCHING UNITS WITH FIBER PAIR SWITCHING
FIG1 is a schematic illustration of one example of an optical communication system consistent with the present disclosure
FIG1 illustrates an exemplary branched optical communication system 100 consistent with the present disclosure. The system 100 has been depicted in highly-simplified form for ease of explanation. The illustrated system 100 includes land-based trunk terminals 110 and 120 coupled to a trunk cable 112, and a land-based branch terminal 160 coupled to the trunk cable 112 through a branch cable 162. In some embodiments, the system 100 may be configured as a long-haul system, e.g. having a length between at least two of the terminals of more than about 600km, which spans a body of water, e.g. an ocean. The trunk cable 112 may thus span between beach landings. Consistent with present disclosure, at least one fiber pair switching branching unit (FPS-BU) 130 may be coupled to the trunk cable between the trunk terminals 110, 120. As will be described in greater detail below, the FPS-BU 130 is configured to allow remote and selectively controllable routing of trunk cable fiber pairs to branch cable fiber pairs. In some embodiments, the FPS-BU 130 is configured to allow remote and selectively controllable routing of two or more trunk cable fiber pairs to a fewer number of branch cable fiber pairs. Although the FPS-BU 130 is illustrated as a single element in FIG1, it is to be understood that the functionality of the FPS-BU 130 may be integrated into a single element disposed in a single housing, or portions of the functionality may be physically separate from each other, e.g. by several kilometres or by one or more water depths to allow the elements to be retrieved from an ocean floor for repair or replacement independently of one another. Although illustrated a separate element in FIG1, the WMU 150 may be integral with the FPS-BU 130 or a portion thereof, i.e. incorporated into the housing of the FPS-BU 130, or may be physically separate therefrom, e.g. by several kilometers or one or more water depths. The FPS-BU 130 and the optional WMU 150 may be coupled to the branch terminal 160 through the branch cable 162. The FPS-BU 130 and WMU 150 may together form a branching configuration 163. The FPS-BU 130 allows selectively controllable routing of trunk cable fiber pairs to branch cable fiber pairs and, optionally via the WMU 150, directs optical signals to and from the branch cable 162 and branch terminal 160, by dropping and adding allocated channel wavelengths.
schematic
160
branch terminal branch terminals
130
FPS-BU
100
system
170
repeaters
112
cable
162
branch cable branch cables
163
branching configuration
110
terminals
150
WMU
114
e.g. cable segments
120
includes land-based trunk terminals
['1. An optical communication system comprising: a trunk terminal configured to provide trunk signals on a plurality of fiber pairs of a trunk cable; a branch terminal configured to provide a branch add signal on a branch cable; and a fiber pair switching branching unit coupled to the trunk cable and the branch cable for receiving the trunk signals and the branch add signal, the branching unit comprising: at least a first optical routing device coupled to the trunk cable and configured to receive the trunk signals from each of the plurality of fiber pairs, the first optical routing device being controllable to couple signals from selected one of the plurality of fiber pairs to a drop fiber of the branch cable; and at least a second optical routing device coupled to the branch cable and configured to receive the branch add signal from the branch cable, the second optical routing device being controllable to couple the branch add signal to a fiber of one of the plurality of fiber pairs.']