TECHNICAL FIELD

This disclosure relates generally to the field of undersea communication networks and relates more particularly to submarine cable branching nodes with fiber pair switching.

BACKGROUND

Submarine optical cables are laid on the seabed or ocean floor between land-based terminals to carry optical signals across long stretches of ocean and sea. The optical cables typically include several optical fiber pairs and other components such as strengthening members, a power conductor, an electrical insulator and a protective shield. The optical fibers may be single core/mode fibers or multi-mode/core fibers. The first fiber of a fiber pair may be coupled in the system for communicating signals in a first direction on the cable and the second fiber of the fiber pair may be configured for communicating signals in a second direction, opposite the first direction, on the cable to support bi-directional communications.

In a branched submarine optical communication system, a trunk cable may extend between first and second land-based trunk terminals. The trunk cable may include a number of trunk cable segments coupled between optical amplifiers for amplifying the optical signals and may have one or more branching nodes coupled thereto. Each branching unit may be connected to a branch cable that terminates in a transmitting and/or receiving land-based branch terminal. The branch cable may include a number of branch cable segments coupled between optical amplifiers for amplifying the optical signals.

BRIEF SUMMARY

In one aspect, an undersea fiber optic cable routing system is provided. The undersea fiber optic cable routing system includes a branching unit coupled to three fiber optic cables. Each fiber optic cable having a number of fiber pairs. The branching unit may include a number of switches for each fiber pair. The number of switches are configurable to enable a a fiber pair from any one of the three fiber optic cables may be switched to allow routing to either of the other two cable fiber optic cables, and a controller operable to receive remote command signals and to configure the number of switches as indicated by the received remote command signal.

In another aspect, an undersea fiber optic cable routing system that includes a first undersea fiber optic cable, a second undersea fiber optic cable, and a third fiber optic cable, and a branching unit is provided. Each of the first, second and third undersea fiber optic cables includes a number of fiber pairs. The branching unit may be configured to couple to each of the first, second and third undersea fiber optic cables. The branching unit includes a first set of assignable switches, a second set of assignable switches, a third set of assignable switches, a number of optical pathways, and a controller. The first set of assignable switches may be configured to optically couple to the plurality of fiber pairs in the first undersea fiber optic cable, where each assignable switch in the first set is coupled to a respective fiber pair in the first fiber optic cable. The second set of assignable switches may be configured to optically couple to the number of fiber pairs in the second undersea fiber optic cable and the third set of assignable switches may be configured to optically couple to a third undersea fiber optic cable. Each assignable switch in the second set is coupled to a respective fiber pair in the second fiber optic cable and each assignable switch in the third set is coupled to a respective fiber pair in the third fiber optic cable. The optical pathways are coupled to respective assignable switches in each of the first set, second set and third set of assignable switches to one another. The controller may be coupled to each respective assignable switch in each of the first set, second set and third set of assignable switches, where the controller is operable to assign a respective first set assignable switch from the first set to a respective second set assignable switch and to a respective third set assignable switch.

