Computer-implemented method, system, and program

Abstract

To provide a computer-implemented method, system, and program for implementing submarine cable branching nodes with fiber pair switching.SOLUTION: A computer-implemented method includes the steps of: selecting, by using at least one processor, at least one or more fiber pairs of a plurality of fiber pairs in one or more submarine cables connecting one or more transmission sites for routing at least one transmission; assigning one or more optical switches to the respective selected fiber pairs of the selected one or more fiber pairs; forming one or more dedicated optical paths, by using the selected one or more fiber pairs and the assigned one or more optical switches; and performing the at least one transmission between the one or more transmission sites, by using the formed one or more dedicated optical paths (dashed lines).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 002,981, filed March 31, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates generally to the field of undersea communication networks, and more particularly to undersea cable branching nodes with optical fiber pair switching. [Background technology]

[0003] Submarine optical fiber cables are laid on the seabed or undersea floor between land terminals to carry optical signals over long distances across the ocean. Optical cables typically include several optical fiber pairs and other components, such as strength members, power conductors, electrical insulators, and protective shields. The optical fibers may be single-core / mode optical fibers or multimode / core optical fibers. To support bidirectional communication, a first optical fiber of the optical fiber pair may be coupled in the system to communicate signals in a first direction on the cable, and a second optical fiber of the optical fiber pair may be positioned to communicate signals in a second direction opposite the first direction on the cable.

[0004] In a branched submarine optical communication system, a trunk cable may extend between a first terrestrial trunk terminal and a second terrestrial trunk terminal. The trunk cable may include multiple trunk cable segments coupled between optical amplifiers for amplifying optical signals and may have one or more branching nodes coupled thereto. Each branching unit may connect to a branching cable that terminates at a transmitting and / or receiving terrestrial branching terminal. The branching cable may include multiple branching cable segments coupled between optical amplifiers for amplifying optical signals. Summary of the Invention

[0005] In one aspect, a submarine optical fiber cable routing system is provided. The submarine optical fiber cable routing system includes a branching unit coupled to three optical fiber cables, each having a plurality of optical fiber pairs. The branching unit may include a plurality of switches for each optical fiber pair. The plurality of switches may be configured to switch an optical fiber pair of any of the three optical fiber cables so that the optical fiber pair of any of the three optical fiber cables can be routed to any of the other two optical fiber cables, and a controller is operable to receive a remote command signal and to configure the plurality of switches according to the received remote command signal.

[0006] In another aspect, a submarine optical fiber cable routing system is provided, the submarine optical fiber cable routing system including a first submarine optical fiber cable, a second submarine optical fiber cable, a third submarine optical fiber cable, and a branching unit. The first submarine optical fiber cable, the second submarine optical fiber cable, and the third submarine optical fiber cable each include a plurality of optical fiber pairs. The branching unit may be configured to be coupled to each of the first submarine optical fiber cable, the second submarine optical fiber cable, and the third submarine optical fiber cable. The branching unit may include a first set of allocatable switches, a second set of allocatable switches, a third set of allocatable switches, a plurality of optical paths, and a controller. The first set of allocatable switches may be configured to be optically coupled to a plurality of optical fiber pairs in the first submarine optical fiber cable, where each allocatable switch in the first set is coupled to a corresponding optical fiber pair in the first optical fiber cable. The second set of allocatable switches may be configured to be optically coupled to a plurality of optical fiber pairs in a second submarine optical fiber cable, and the third set of allocatable switches may be configured to be optically coupled to a third submarine optical fiber cable. Each allocatable switch in the second set is coupled to a corresponding optical fiber pair in the second optical fiber cable, and each allocatable switch in the third set is coupled to a corresponding optical fiber pair in the third optical fiber cable. An optical path is coupled to each allocatable switch in each of the first set of allocatable switches, the second set of allocatable switches, and the third set of allocatable switches. A controller may be coupled to each corresponding allocatable switch in each of the first set of allocatable switches, the second set of allocatable switches, and the third set of allocatable switches, wherein the controller is operable to assign a corresponding first set allocatable switch from the first set to a corresponding second set of allocatable switches and a corresponding third set of allocatable switches. [Brief explanation of the drawings]

[0007] In the accompanying drawings, like reference numerals generally refer to like parts in all different views.In the following description, various embodiments of the present disclosure will be described with reference to the accompanying drawings, in which:FIG.

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating an exemplary branched optical communication system.

[0009] [Figure 2] FIG. 1 shows a branching unit between three submarine cables, where each optical fiber pair has a special optical fiber switching configuration.

[0010] [Figure 3] FIG. 1 is a diagram of fiber optic pair switching connectivity between three sites, showing the switching connections between each fiber optic pair in each cable.

[0011] [Figure 4] FIG. 10 is a diagram of an alternative embodiment of the present invention linking the optical fiber pairs in each cable into larger, more flexible rearrangement sets.

[0012] [Figure 5] 5A and 5B show links between two optical fiber pairs in each of three cables in the switching configuration shown in FIG. 4.

[0013] [Figure 6] 10A-10C illustrate branching units including an example of an additional repositionable member coupled to a cable, arranged in an example branching unit architecture.

[0014] [Figure 7] FIG. 10 illustrates another example of an architecture configuration of a branching unit.

[0015] [Figure 8] FIG. 10 is a diagram illustrating another example of the architecture configuration of a branching unit.

[0016] [Figure 9] FIG. 1 is a diagram illustrating an example of a branching unit control configuration in a submarine optical fiber cable routing system. DETAILED DESCRIPTION OF THE INVENTION

[0017] The systems and devices according to the present disclosure are more fully described below with reference to the accompanying drawings, in which one or more embodiments are shown. These systems and devices may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the disclosure will be thorough and complete, and will fully convey the scope of the methods and devices to those skilled in the art. Each of the systems, devices, and methods disclosed herein offers one or more advantages over conventional systems, devices, and methods.

[0018] Submarine cables are typically implemented using a trunk and branch architecture, as previously described. A typical connection architecture designates two cables as the "trunk" cable and a third cable as the "branch" cable. At the network unit, fiber optic switches at each trunk optical fiber pair are configured to connect or bypass a single trunk optical fiber pair to a corresponding set of branch optical fiber pairs. In the new configuration described herein, there is no trunk or branch designation.

[0019] The disclosed subject matter provides the ability to aggregate three trunk cables by providing a new switching architecture to provide reconfigurable routing flexibility among the optical fiber pairs in all three cables. The new switching architecture allows for connecting "any two of the three trunk cables" on an individual optical fiber, individual optical fiber pair, or individual optical fiber pair set basis. Other technical features will become apparent to those skilled in the art from the accompanying drawings, description, and claims.

[0020] The assignable switches described herein can be configured to connect any two of three fiber optic pairs, one from each of three cables, and can provide fiber optic pair selectability anywhere between one "three" fiber optic pair (e.g., 1x1x1) to N three fiber optic pairs (e.g., NxNxN), where N is the number of fiber optic pairs in the cable having the lowest number of fiber optic pairs.

[0021] FIG. 1 illustrates an exemplary branched optical communication system 100. For ease of explanation, system 100 is depicted in a highly simplified form. The illustrated system 100 includes terrestrial trunk terminals 110, 120 coupled to trunk cable 112 and a terrestrial branch terminal 160 coupled to trunk cable 112 by a branch cable 162. In some embodiments, system 100 may be configured as a long-haul system, e.g., having a length greater than about 600 km between at least two of the terminals, spanning a body of water, e.g., the ocean. Trunk cable 112 is thereby spanned between beach landings.

[0022] Both the trunk cable 112 and the branch cable 162 may include multiple optical cable segments, such as cable segments 114, 115, and 116, for carrying optical signals (e.g., wavelength division multiplexed (WDM) optical signals). Each cable segment may include one or more optical cable segments and one or more repeaters 170. Each optical cable segment may employ a known configuration, including multiple optical fiber pairs, one or more strength member layers, electrical power conductors, insulation, and an armored cover section. The optical fiber pairs and power conductors of the optical cable are protected within the cable by the armored cover section, member, and protective cover.

[0023] Thus, system 100 may be configured to provide bidirectional communication of optical signals to and from any of terminals 110, 120, 160. For ease of explanation, descriptions herein may refer to transmission from one terminal to another. However, it should be understood that system 100 may be configured to be used for bidirectional or unidirectional communication between any number of terminals 110, 120, 160.

[0024] At least one fiber pair switching branching unit (FPS-BU) 130 can be coupled to the trunk cable between the trunk terminals 110, 120. As described in more detail below, the FPS-BU 130 is configured to allow remote and selectively controllable routing of the optical fiber pairs of the trunk cable to the optical fiber pairs of the branch cable. In some embodiments, the FPS-BU 130 is configured to allow remote and selectively controllable routing of two or more optical fibers of the trunk cable to a fewer number of optical fiber pairs of the branch cable. Although the FPS-BU 130 is shown as a single element in FIG. 1 , it should be understood that the functionality of the FPS-BU 130 can be integrated into a single element disposed within a single housing, or functional portions can be physically separated from one another, for example, by several kilometers or one or more water depths, allowing elements to be retrieved from the seabed for repair or replacement independently of one another.

[0025] FPS-BU 130 may be associated with a selectable wavelength management unit (WMU) unit 150 configured to provide selective wavelength filtering to signals on the optical fiber pairs of the branch cable coupled to FPS-BU 130.

[0026] FIG. 2 illustrates a first embodiment, showing three cables 210, 212, and 224 from three sites 202a, 202b, and 202c, respectively, connected to a branching unit 214. The three sites 202a, 202b, and 202c transmit information via their respective cables 210, 212, and 224 by outputting it as an optical signal. Each cable 210, 212, or 224 has a certain number of optical fiber pairs, and each optical fiber pair in each cable has two optical fibers. For example, optical fiber pair 234 from submarine optical fiber cable 224 has one inbound optical fiber 238 to site 2 202b and one outbound optical fiber 236 from site 2 202b, allowing bidirectional communication between sites 202a and 202b. For example, submarine optical fiber cable 210 has an optical fiber pair including inbound optical fiber 208 and outbound optical fiber 232.

[0027] Branching unit 214 may include multiple assignable switches 204, 206, 216, 218, 220, and 222 and multiple optical paths (e.g., 228 and 230) coupling each of the assignable switches to one another. Branching unit 214 is configured to permit remote and selective controllable routing of optical fiber pairs in response to remote command signals. The remote command signals for configuring the switches may be transmitted, for example, on a supervisory channel of a wavelength division multiplexed signal transmitted on any one of the three cables 210, 212, or 224. Branching unit 214 may include a controller 226 that extracts the remote command signals from the supervisory channel and is used to configure the switches in response to the remote command signals. In alternative embodiments, the remote command signals are transmitted to branching unit 214 and returned to controller 226 by any known method, including, for example, transmitting the remote command signals on the optical fibers of the optical fiber pair being switched (e.g., optical fiber 208 and optical fiber 232).

[0028] Figure 2 illustrates the switching of optical fiber pairs from each cable. The embodiment of Figure 2 can route a single optical fiber pair within each cable 210, 212, or 224. The embodiment shows one optical fiber pair from each of three cables connected via an assembly of six 1x2 optical switches. However, switches with other ratios can be used, such as 2x2 blocking, 2x2 non-blocking, or higher ratio switches.

[0029] To change the optical fiber path (e.g., change the path from connection site 202a to site 202c to the path from connection site 202a to site 202b), the optical switches in the two optical fiber branching units 214 must be configured by controller 226. To establish an optical path for one optical fiber in the optical fiber pair, two of the three switches for that optical fiber are configured to couple to the correct switch. For example, one "tip" switch (e.g., switch 204) for inbound optical fiber 208 and one "selector" switch (e.g., switch 206) for coupling to outbound optical fiber 236. Switch 206 may be a switch corresponding to switch 204, and switch 216 may be a switch corresponding to switch 220. The corresponding switch is an optically assignable switch in another cable that matches the direction of the optical signal stream. In this example, two optical fibers of the optical fiber pair follow the same route between sites, i.e., two optical fibers in the optical fiber pair (e.g., 208 and 232 at site 202a) are switched (e.g., using switches 204 and 220) and coupled to corresponding optical fibers 236 and 238, respectively, of optical fiber pair 234 in cable 224. When the above-described switching is completed, optical signals cannot be routed from switches 218 and 222 in cable 212 to switches 204 and 220 in cable 210. Furthermore, optical signals cannot be routed from switches 218 and 222 in cable 212 to switches 206 and 216 in cable 224. The preceding description described the formation of switching triangles between switches 204, 206, and 218 for each of cables 210, 212, and 224, and the corresponding switching triangles for switches 220, 216, and 222.

[0030] If one submarine fiber optic cable has fewer fiber optic pairs than the other submarine fiber optic cables, the number of fiber optic pairs supported is limited to this number. For example, if two fiber optic cables in a three-fiber cable set have 16 fiber optic pairs and the third fiber optic cable has only 6 fiber optic pairs, only the six fiber optic pairs from each of the three cables are arranged in a "two-in-three" configuration.

[0031] 3 illustrates a deployment of fiber pair switching (as shown in FIG. 2) for switching between three submarine fiber optic cables, where each submarine fiber optic cable in FIG. 3 has 16 fiber optic pairs. The submarine fiber optic cable routing system 300 includes sites 304, 306, and 308, submarine fiber optic cables 312, 314, and 316, and a deployable branching unit 310.

[0032] Sites 304, 306, and 308 may provide optical signals (not shown) containing information that may be used for further transmission or received from other corresponding sites (e.g., site 304 exchanges optical signals with site 306, and site 308 exchanges optical signals with site 304, etc.). Each site 304, 306, 308 may include hardware such as processors, servers, lasers, optical modulators, optical demodulators, electrical-to-optical switching equipment, optical amplifiers, repeaters, etc. Like submarine fiber optic cables 210, 212, and 224 in Figure 2, submarine fiber optic cables 312, 314, and 316 include multiple optical fiber pairs.

[0033] Submarine fiber optic cables 312 , 314 and 316 are optically coupled to corresponding sites 304 , 306 and 308 at first ends and coupled to branching unit 310 at second ends.

[0034] The deployable branching unit 310 may include a plurality of optical switches as assignable switches, a plurality of optical paths 320, a controller 322, and a housing 324. The housing 324 is configured to protect the plurality of optical switches (e.g., optical switch 302), the plurality of optical paths 320, and the controller 322. The controller 322 may be located within the housing 324 of the selectively deployable branching unit 310.

[0035] In the example of Figure 3, submarine fiber optic cable 312 includes 16 optical fiber pairs (e.g., optical fiber pair 326), which are coupled to allocatable switches (e.g., 302) in a plurality of allocatable switches in deployable branching unit 310. Although there are 16 allocatable optical switches 302 for each optical fiber pair shown in the example of Figure 3, in reality there are 32 optical allocatable switches 302, i.e., one optical allocatable switch for the inbound optical fibers and one optical allocatable switch for the outbound optical fibers of the 16 optical fiber pairs to be shown for each of fiber optic cables 312, 314, and 316.

[0036] In the exemplary deployable branching unit 310, one optical fiber from each of the cables 312, 314, and 316 can be assigned by the controller 322 to one "switch triangle" 318 between the three cables 312, 314, and 316. While Figure 3 shows an example of the switch triangle 318, it is one of three example switch triangles shown, one skilled in the art should recognize that there can be a switch triangle for each corresponding optical fiber pair from each cable 312, 314, and 316.

[0037] Switching triangle 318 shows three possible connection paths for each set of optical fiber pairs (i.e., optical fiber pair 326 of submarine optical fiber cable 312, optical fiber pair 328 of submarine optical fiber cable 314, and optical fiber pair 330 of submarine optical fiber cable 316) in deployable branching unit 310. Only one side of switching triangle 318 is activated at a time, thereby forming a connection between two of the three sites. The other two sides of switching triangle 318 are cut by corresponding optical switches 302 at each vertex of switching triangle 318.

[0038] The embodiments shown in Figures 2 and 3 provide novel optical switching configurations in a submarine cable environment. Branching unit 214 and deployable branching unit 310 may be configured to connect two of the three sites for each optical fiber pair. For each optical fiber pair, the first site (e.g., site 202a in Figure 2 or site 304 in Figure 3) can be connected to the second site (e.g., site 202b in Figure 2 or site 306 in Figure 3) while the third site (e.g., site 202c in Figure 2 or site 308 in Figure 3) is disconnected. Alternatively, the first site (e.g., site 202a in Figure 2 or site 304 in Figure 3) can be connected to the third site (e.g., site 202c in Figure 2 or site 308 in Figure 3) while the second site (e.g., site 202b in Figure 2 or site 306 in Figure 3) is disconnected. In another alternative embodiment, a second site (e.g., site 202b in FIG. 2 or site 306 in FIG. 3) can be connected to a third site (e.g., site 202c in FIG. 2 or site 308 in FIG. 3) while the first site (e.g., site 202a in FIG. 2 or site 304 in FIG. 3) is disconnected. Any "odd" number of remaining fiber optic pairs in any cable can be managed using a single fiber optic pair architecture (as shown in the embodiments of FIGS. 2 and 3).

[0039] Figure 4 is a diagram of an alternative embodiment of the invention that links optical fiber pairs in each cable into larger, more flexible relocation sets. In a submarine optical fiber cable routing system 400, site 402, site 404, and site 406 are coupled to a branching unit 408. In the example of Figure 4, a selected set is expanded to include two optical fiber pairs in each corresponding cable 410, 412, and 414. In the example of Figure 4, a controller 416 has the capability to select and switch between two sets of optical fiber pairs. The controller 416 is operable to designate any two optical fiber pairs in each cable 410, 412, and 414 as part of the same selected set. For example, a remote command signal can be received that instructs the controller to designate any two optical fiber pairs from the corresponding cable 410, 412, or 414, or from the corresponding sites 404, 402, and 406, to perform the switch by designating them as part of the selected set.

[0040] In this example, a first optical fiber pair at site 402 in cable 412 (i.e., site 402FP1) and a second optical fiber pair at site 402 (i.e., site 402FP2) can be designated by controller 416 as part of a selected set. Controller 416 can also complete the selected set by designating optical fiber pairs (e.g., site 404FP1, site 404FP2, site 406FP1, site 406FP2) in corresponding cables 410, 414. Once the selected set is designated, controller 416 can assign two optically assignable switches coupled to each designated optical fiber pair (e.g., site 402FP1, site 404FP1, and site 406FP1) to be coupled to each other via optical paths (as shown by dashed lines). In this example, the two optically allocable switches for each designated optical fiber pair (e.g., site 402FP1) coupled to cable 412 can be coupled via dedicated optical paths to one or two sets of optically allocable switches for the designated optical fiber pair (i.e., site 406FP1) coupled to cable 414. Similarly, the two optically allocable switches for each designated optical fiber pair (e.g., site 406FP1) coupled to cable 414 can be coupled via dedicated optical paths to one or two sets of optically allocable switches for the designated optical fiber pair (i.e., site 406FP1) coupled to cable 410.

[0041] 4 provides additional flexibility by allowing the placement of two connected optical fiber pairs for each selected set, for example, two optical fiber pairs connecting site 402 to site 404 if site 406 is disconnected; two optical fiber pairs connecting site 402 to site 406 if site 404 is disconnected; or two optical fiber pairs connecting site 404 to site 406 if site 402 is disconnected.

[0042] Figure 5 shows an alternative view of the links between two optical fiber pairs in each of three cables in a switch fabric, such as the switch fabric shown in Figure 4. In this example, a submarine optical fiber cable routing architecture 500 includes cables 502, 504, and 506 and a branching unit 520. In this example, cables 502, 504, and 506 each include 16 optical fiber pairs (inbound and outbound optical fibers). As shown in the previous example, branching unit 520 has 32 corresponding assignable optical switches that are coupled to corresponding inbound and outbound optical fibers. In this example, the controller designates the outermost optical fiber pairs to be coupled together. The designated couplings interconnect cables 502, 504, and 506 in the following order: from cable 502FP1 to cable 504FP1, from cable 504FP1 to cable 506FP1, from cable 506FP1 to cable 502FP2, from cable 502FP2 to cable 504FP2, and from cable 504FP2 to cable 506FP2. The controller further assigns optical allocable switches to route the designated optical fiber pairs according to the designated couplings. For example, the controller can assign optical allocable switch 508 (for cable 502) to corresponding optical allocable switch 510 (for cable 504) and corresponding optical allocable switch 514 (for cable 506). The controller can further assign optical allocable switch 516 (for cable 502) to corresponding optical allocable switch 512 (for cable 504) and corresponding optical allocable switch 518 (for cable 506). Each optically assignable switch includes a switch for coupling to each optical fiber of a corresponding optical fiber pair, thereby providing bidirectionality.

[0043] Branching unit 520 includes a plurality of optical paths interconnecting each of optically assignable switches 508-518, e.g., 522, 524, 526, 528, 530, and 532. Each optically assignable switch is coupled to two optical paths. For example, optically assignable switch 518 is optically coupled to optically assignable switch 516 via optical path 530 and to optically assignable switch 510 via optical path 524. Similarly, optically assignable switch 516 is optically coupled to optically assignable switch 512 via optical path 526. As with the previous example, only one optical path of each switch is active at a given time. Based on which optical paths are activated, the optically assignable switches can be controlled to place branching unit 520 in one of five different states.

[0044] 6 shows an exemplary state of optical fiber pairs in a branching unit. In the illustrated example, for ease of illustration and interpretation, the cable at each site is shown providing two optical fiber pairs to branching unit 600. Each of the optical fiber pairs includes two optical fibers, an inbound optical fiber and an outbound optical fiber. One optical allocatable switch is disposed in branching unit 600 for each optical fiber of the optical fiber pairs. In branching unit 600, a first optical fiber pair at site 1 is coupled to two optical allocatable switches indicated by optical allocatable switch 602, and a second optical fiber pair is coupled to two other optical allocatable switches indicated by optical allocatable switch 604. Similarly, the first optical fiber pair at Site 2 is coupled to two optically allocable switches indicated by optically allocable switch 606, and the second optical fiber pair is coupled to two other optically allocable switches indicated by optically allocable switch 608, and the first optical fiber pair at Site 3 is coupled to two optically allocable switches indicated by optically allocable switch 610, and the second optical fiber pair is coupled to two other optically allocable switches indicated by optically allocable switch 612.

[0045] A controller (not shown in this example) is responsive to remote command signals and controls the state of the optical fiber pairs designated for routing in branching unit 600 by sending commands to the optical assignable switches corresponding to the optical fiber pairs designated for routing. In response to the remote command signals, branching unit 600 is placed.

[0046] In State 1, each optical allocatable switch 602 and 604 at Site 1 in branching unit 600 is configured to be able to distribute optical signals from Site 1 to corresponding optical allocatable switches 612 and 610 (as shown by solid lines) at Site 3. In State 1, optical allocatable switch 602 and optical allocatable switch 604 at Site 1 are inactivated (as shown by dashed lines) while the optical path between optical allocatable switch 608 and optical allocatable switch 606 at Site 2 is deactivated.

[0047] In State 2, each optical allocatable switch in branching unit 600 is configured to distribute optical signals from optical allocatable switches 606 and 608 in Site 2 to corresponding optical allocatable switches 612 and 610 in Site 2. In State 2, the optical paths between optical allocatable switches 606 and 608 in Site 2 and corresponding optical allocatable switches 604 and 602 in Site 1, and between optical allocatable switches 602 and 604 in Site 1 and corresponding optical allocatable switches 612 and 610 in Site 3 are all deactivated (as indicated by dashed lines).

[0048] In State 3, each optically allocable switch in branching unit 600 is configured to be able to distribute optical signals from allocable optical switches 606 and 608 in Site 2 to corresponding optically allocable switches 604 and 602 in Site 1. In State 2, the optical paths between optically allocable switches 606 and 608 in Site 2 and corresponding optically allocable switches 612 and 610 in Site 3, and the optical paths between optically allocable switches 602 and 604 in Site 1 and corresponding optically allocable switches 612 and 610 in Site 3 are all deactivated (as shown by dashed lines).

[0049] States 1-3 are two optical fiber pair states in which two optical fiber pairs from a first site are routed to a second site. However, one of the other improvements and advantages of the disclosed routing architecture and submarine optical fiber cable routing system is the ability to specifically route a first optical fiber pair from a first site to a second site and a second optical fiber pair from the first site to a third site. Examples of states 4 and 5 illustrate these advantageous configurations.

[0050] In state 4, a first optical fiber pair at Site 1 coupled to optical allocatable switch 602 is routed to a corresponding first optical fiber pair at Site 3 by being coupled to optical allocatable switch 612, a second optical fiber pair at Site 1 coupled to optical allocatable switch 604 is routed to a corresponding first optical fiber pair at Site 2 by being coupled to optical allocatable switch 606, and a second optical fiber pair at Site 2 coupled to optical allocatable switch 608 is routed to a corresponding second optical fiber pair at Site 3 by being coupled to optical allocatable switch 610.

[0051] State 5 provides a variation of State 4, demonstrating the flexibility it provides to the controller in specifying each optical fiber pair used for routing. In State 5, a first optical fiber pair at Site 1 coupled to optical allocatable switch 602 is routed to a corresponding first optical fiber pair at Site 2 by being coupled to optical allocatable switch 608, a third optical fiber pair at Site 1 coupled to optical allocatable switch 604 is routed to a corresponding first optical fiber pair at Site 2 by being coupled to optical allocatable switch 610, and a second optical fiber pair at Site 2 coupled to optical allocatable switch 606 is routed to a corresponding second optical fiber pair at Site 3 by being coupled to optical allocatable switch 612.

[0052] Specifying the routing capability of each optical fiber pair allows the controller to respond with a remote command specifying any number of sets of each optical fiber pair to be used for routing. For example, sets of 2, 5, 15, 24, up to N are possible, where N is the cable with the minimum number of optical fiber pairs. This routing capability allows the optical signal distribution system to respond to changes in demand, equipment failures and interruptions, etc.

[0053] As shown in the following examples, the benefits of the routing architecture and submarine fiber optic cable routing system shown in and described in the previous examples can be further enhanced by incorporating additional switching capabilities.

[0054] FIG. 7 shows another example of a branching unit configuration incorporating additional spectrum routing devices.

[0055] 7, submarine optical fiber cable routing system 700 includes a first submarine optical fiber cable 716 from a first site 710, a second submarine optical fiber cable 718 from a second site 712, and a third optical fiber cable 720 and branching unit 722 from a third site 714. Each of first submarine optical fiber cable 716, second submarine optical fiber cable 718, and third submarine optical fiber cable 720 includes a plurality of optical fiber pairs. In this example, the number of optical fiber pairs is 16, although the number of optical fiber pairs may also be 3, 8, 9, 12, 24, etc.

[0056] Branching unit 722 may be configured to couple to each of first submarine fiber optic cable 716, second submarine fiber optic cable 718, and third submarine fiber optic cable 720, thereby allowing optical signals to be routed (or "branched") from one of the fiber optic cables to the other. Branching unit 722 further includes a first set of optically allocable switches 724 arranged to be optically coupled to a plurality of optical fiber pairs in first submarine fiber optic cable 716, a second set of optically allocable switches 726 arranged to be optically coupled to a plurality of optical fiber pairs in second submarine fiber optic cable 718, and a third set of optically allocable switches 728 arranged to be optically coupled to a plurality of optical fiber pairs in third submarine fiber optic cable 720. Each allocable switch in the first set of optically allocable switches 724 may be coupled to a corresponding optical fiber pair in first fiber optic cable 716. Similarly, each allocatable switch in the second set of allocatable switches 726 is coupled to a corresponding optical fiber pair in the second optical fiber cable 718, and each allocatable switch in the third set of allocatable switches is coupled to a corresponding optical fiber pair in the third optical fiber cable.

[0057] The branching unit 722 further includes a plurality of optical paths (collectively designated 702) coupling each of the assignable switches of the first set of assignable switches 724, the second set of assignable switches 726, and the third set of assignable switches to one another.

[0058] A controller 730 may be coupled to each corresponding allocatable switch in each of the first set of allocatable switches 724, the second set of allocatable switches 726, and the third set of allocatable switches. The controller 730 is operable to allocate a corresponding first set of allocatable switches from the first set of allocatable switches 724 to a corresponding second set of allocatable switches in the second set 726 and a corresponding third set of allocatable switches in the third set 728.

[0059] In the example system 700, the number of designated optical fiber pairs to switch may be 16 x 16 x 16. For example, the controller 730 is operable to assign corresponding optical allocable switches in the first set of allocable switches 724 to corresponding allocable switches in the second set of allocable switches 726 and the third set of allocable switches, respectively. Based on the assignments to corresponding allocable switches in the first, second, and third sets, a "switching triangle" (e.g., 727) may be formed.

[0060] The optical cable routing system further includes a plurality of ROADMs 704, 706, and 708 for selected optical fiber pairs of the first submarine optical fiber cable (716), the second submarine optical fiber cable (718), and the third submarine optical fiber cable (720), respectively. Each corresponding reconfigurable optical add / drop multiplexer of the plurality of reconfigurable optical add / drop multiplexers is coupled to a corresponding selected optical fiber pair before the corresponding selected optical fiber pair is coupled to a corresponding allocatable switch. For example, the corresponding reconfigurable optical add / drop multiplexer 708 is coupled to the cable 720 before the cable 720 is coupled to the branching unit 722 and the third set of allocatable optical switches 788.

[0061] The additional spectrum routing device referred to in the description of FIG. 7 may be a reconfigurable optical add / drop multiplexer (ROADM) incorporated before the optically assignable switch of the branching unit. As previously described, submarine optical fiber cables 716, 718, and 720 carry optical signals transmitted at different optical wavelengths. Different optical fibers (e.g., inbound optical fibers) within the cables may carry different wavelengths of light. The ROADM is configured to traverse multiple fibers of two types, with the inbound optical fibers being one type and the outbound optical fibers being the other type. The ROADM may be controlled by a controller (shown in another example), which also controls the branching unit. A ROADM may be configured to combine a first designated set of wavelengths from one input (e.g., a first inbound optical fiber) with a second designated set of wavelengths of different wavelengths from another input (e.g., a second inbound optical fiber), thereby allowing the first designated set of wavelengths and the second designated set of wavelengths to share a pair of inbound optical fibers. For example, once combined, the combined wavelengths can share the first inbound optical fiber, the second inbound optical fiber, or both the first and second inbound optical fibers.

[0062] In an example referring to the states and ROADMs of FIG. 6 , a ROADM, such as 706, can be attached to two fiber pairs of a cable 718 at a second site 712. A controller 730 can receive a remote command signal to perform the switch by designating the two optical fiber pairs to be coupled to the ROADM 706. The corresponding two optical fiber pairs coupled to the ROADM 706 can be configured as shown in state 4 of FIG. 6 , whereby the controller 730 causes an optical signal on one of the two optical fiber pairs coupled to the ROADM 706 to be guided from the second site 712 to the first site 710. An optical signal on the other optical fiber pair coupled to the ROADM 706 can be guided to a third site 714. An optical fiber pair at the first site 710 can be coupled to an optical fiber pair at the third site 714. The ROADM 706 allows the two optical fiber pairs to share the optical wavelength spectrum transmitted over the two shared optical fiber pairs. If the optical fiber pairs coupled to the ROADM 706 carry a larger portion of the optical wavelength spectrum from the second site 712, the ROADM 706 can share the spectrum. However, the controller 730 can convey a signal to switch the state of the optical fiber pairs from State 4 (all 1 FPs on the path) to State 2. In State 2, two optical fiber pairs coupled to the ROADM 706 and corresponding allocatable switches 728 are designated for switching to accommodate the larger portion of the spectrum. In response to the designation of the switch, the controller 730 issues a control signal to redistribute the corresponding allocatable switches in the second set of allocatable switches coupled to the two optical fiber pairs switched to State 2. By switching to State 2, the shared optical wavelength spectrum is distributed for transmission to the third site. Alternatively, returning when the corresponding optical fiber pair is placed in state 2, the ROADM 706 can identify that the optical fiber pair from the first site 710 carries a larger portion of the optical wavelength spectrum by monitoring the corresponding optical fiber pair coupled to the ROADM 706 and carrying optical signals to / from the first site 710.As a result, the ROADM can forward this information to the controller 730, which causes the optical fiber pair's corresponding allocation switch to change to state 1, where the optical fiber pair previously coupled to the ROADM 706 from the first site 710 is now switched and coupled to the allocation switch that directs the optical signal of one optical fiber pair from the first site 710 to the third site 714.

[0063] Another example of a branching unit architecture configuration is shown in Figure 8. Deployable branching unit 800 provides selective delineation of fiber optic pairs that realizes the concept of any location between one "trio" of fiber optic pairs (e.g., 1x1x1) to N trios of fiber optic pairs (e.g., NxNxN), where N is the number of fiber optic pairs in the fiber optic cable having the minimum number of fiber optic pairs.

[0064] The deployable branching unit 800 can include three sites (site 1 834, site 2 836, and site 3 838), and each submarine fiber optic cable having multiple optical fiber pairs is coupled to the branching unit 842 from these sites. The number of optical fiber pairs in each of the cables shown is 16, but different numbers of optical fiber pairs can be used. Within or connected to each submarine fiber optic cable is a ROADM coupled to each optical fiber pair (see FIG. 7 ). The ROADMs can typically be deployed with two optical fiber pairs facing one of the three sites, although other configurations are possible. For example, the cable from site 1 834 has ROADMS R1 820, R2 818, R3 816, and R4 808, where each ROADM is coupled to a corresponding optical fiber pair (e.g., two optical fiber pairs) of the 16 optical fiber pairs in the cable from site 1 834. Similarly, the cable from Site 2 836 has ROADMs R1 806, R2 828, R3 830, and R4 834, where each ROADM is coupled to a corresponding optical fiber pair (e.g., two optical fiber pairs) of the 16 optical fiber pairs in the cable from Site 2 836, and the cable from Site 3 8386 has ROADMs R1 826, R2 824, R3 822, and R4 804, where each ROADM is coupled to a corresponding optical fiber pair (e.g., two optical fiber pairs) of the 16 optical fiber pairs in the cable from Site 3 838.

[0065] Branching unit 842 is similar to the previous example in terms of the number of optical allocatable switches, optical paths, and responsiveness to commands from controller 840. For example, each cable has a corresponding optical fiber pair coupled to a corresponding optical fiber pair of a corresponding allocatable switch in one set of allocatable switches from a site in branching unit 842. For example, the optical fiber pairs of the cable from site 1 834 are coupled to one set of allocatable switches 844 in branching unit 842, the optical fiber pairs of the cable from site 2 836 are coupled to one set of allocatable switches 846, and the optical fiber pairs of the cable from site 3 838 are coupled to one set of allocatable switches 848.

[0066] As described with respect to the example of Figure 7, the controller 840 in the example of Figure 8 can determine the state settings of corresponding optical allocatable switches in branching units 842 of each cable coupled to Site 1 834, Site 2 836, and Site 3 838. The controller can be operable to respond to remote command signals to separate sets of allocatable switches, where each of the allocatable switch sets includes at least one switch coupled to an optical fiber pair, the optical fiber pair being coupled to a ROADM. The controller can be configured with the state of the sets and can determine the state of each optical fiber pair based on the state of the sets. Examples of operability may be useful.

[0067] In an example of operation, controller 840 may receive a remote command signal specifying which optical fiber pairs to switch and which specified optical fiber pairs to divide into three sets. In response to the remote command signal, controller 840 is operable to subdivide the first set of assignable switches 844 into a first set of sets of assignable switches and the second set of assignable switches 846 into a second set of sets of assignable switches, where the number of assignable switches in each of the sets of states of the second set of assignable switches corresponds to the number of assignable switches in the first set of sets of assignable switches.

[0068] The controller 840 further subdivides the third set of allocatable switches 848 into sets of the third set of allocatable switches, where the number of allocatable switches in each set of the third set of allocatable switches corresponds to the number of allocatable switches in each of the first set of allocatable switches and the second set of allocatable switches. The controller 840 is further operable to allocate corresponding groups from the first set of allocatable switches to corresponding groups from the second set of allocatable switches and the third set of allocatable switches.

[0069] 8 , the controller 840 can subdivide the first set of allocatable switches into a first set of four allocatable switches, which can include those switches coupled to optical fiber pairs in a cable from Site 1 834, which includes ROADM R1 820. The controller can subdivide the allocatable switches from the second set of allocatable switches 846 and the third set of allocatable switches 848 into corresponding sets of four allocatable switches. The controller 840 places the set of four allocatable switches from the first set of allocatable switches 844 and the corresponding group of four allocatable switches from the second set of allocatable switches 846 and the third set of allocatable switches 848 into a control group (e.g., R1-4x4x4 802), which further includes corresponding optical fiber pairs coupled to each cable for the corresponding ROADM R1 820, R1 806, and R1 826. Similarly, the controller can create a control group, such as R2-4x4x4 810, which also includes the corresponding optical fiber pairs of each cable coupled to the corresponding ROADMs R2 816, R2 828, and R2 824. The controller can create control groups with different numbers of assignable switches, such as R3-2x2x2 812, which include a set of two assignable switches from each cable and the corresponding optical fiber pairs of each cable coupled to the corresponding ROADMs R3 818, R2 830, and R2 822. Another control group may be R4-6x6x6 814, which includes a set of six assignable switches from each cable and the corresponding optical fiber pairs of each cable coupled to the corresponding ROADMs R4 808, R4 832, and R8 804.

[0070] The creation of control groups may be limited by the number of allocatable switches in a set, where the size of the set may be based on a minimum number of optical fiber pairs in each of the first submarine fiber optic cable, the second submarine fiber optic cable, and the third submarine fiber optic cable, and each corresponding set may have the same number of allocatable switches.

[0071] Additionally, other flexibility can be provided in the routing of fiber optic pairs among the three cables. One or more sets of fiber optic pairs in each cable can be combined into flexible routing sets of crossed fiber optic pairs. Switch types other than "two in one pair" (connected between one input / output port and two output / input ports) can be used for more complex arrangements, such as 2x2 blocking, 2x2 non-blocking, or larger ratio switches.

[0072] Alternative optical devices can be used for routing, such as wavelength-selective filters. The optical fiber flow propagation direction in each optical fiber can remain constant in all configurations, or can be reversed in some configurations. Configurations can be provided that maintain the coupling of two optical fibers into a single optical fiber pair for all configurations. Additionally, or alternatively, optical fibers within a cable can be allocated so that the optical fiber pairs can be different depending on the configuration. Such functionality can be implemented in alternative ways (including higher-order switching) and is not limited to the architecture shown.

[0073] FIG. 9 shows an example of a branching unit control configuration in a routing system for a submarine optical fiber cable.

[0074] The submarine optical fiber cable routing system 900 may include a controller 902 and a branching unit 904. The branching unit 904 may be configured to couple to a plurality of optical fibers. The number of optical fiber cables may be three, e.g., cable 901 from site A, cable 903 from site B, and cable 905 from site C. Each of the three optical fiber cables 901, 903, and 905 may include N number of optical fiber pairs, e.g., 914, 924, and 956, where N is 2, 4, 5, 12, 16, 24, etc. It should be noted that the branching unit 904 may be configured to receive a different number of optical fiber pairs in each cable. Each optical fiber pair in the plurality of optical fiber pairs in the first submarine optical fiber cable 901 includes an outbound optical fiber (e.g., 938) for outputting an optical signal from a first site (e.g., site A) and an inbound optical fiber 940 for transmitting the optical signal to the first site (i.e., site A). Similarly, each optical fiber pair in the plurality of optical fiber pairs in the second submarine optical fiber cable 903 includes an outbound optical fiber for outputting an optical signal from a second site (e.g., site B) and an inbound optical fiber for transmitting the optical signal to the second site, and each optical fiber pair in the plurality of optical fiber pairs in the third submarine optical fiber cable 905 includes an outbound optical fiber for outputting an optical signal from a third site (e.g., site C) and an inbound optical fiber for transmitting the optical signal to the third site.

[0075] Each of the N optical fiber pairs includes an inbound optical fiber (e.g., 940) and an outbound optical fiber (e.g., 938). In this example, inbound optical fiber 940 can receive optical information (also called an optical signal) from the branching unit, and outbound optical fiber 938 can transmit different optical information (also called an optical signal) to branching unit 904. In Figure 9, cable 901 includes corresponding optical fiber pairs 908, 910, 912, 914, 916, and 918; cable 903 includes corresponding optical fiber pairs 924, 926, 928, 930, 932, and 934; and cable 905 includes corresponding optical fiber pairs 956, 958, 960, 962, 964, and 966.

[0076] Branching unit 904 may include a bus 946 and a switch 936 for the cables. Corresponding optical fiber pairs of cables 901, 903, and 905 may be coupled to corresponding optically assignable switches 936. Each of the optical fiber pairs from cables 901, 903, and 905 may include multiple channels over which optical signals are transmitted, and one of the channels may be a supervisory channel over which remote command signals may be sent. Bus 946 may be coupled to the corresponding switch, allowing controller 902 to monitor the supervisory channel and issue switching instructions to the corresponding switch 936 for the corresponding cable.

[0077] The controller 902 includes a logic circuit system 942, a memory 944, and an electrical-to-optical conversion circuit system 952. The controller 902 can receive, in a remote command signal, a designation of optical fiber pairs to be switched. The controller 902 can be coupled to a bus 946 of the branching unit 904 via a control connection 948, which can be an optical or electrical connection. The control connection 948 enables the logic circuit system 942 to receive the remote command signal and transmit control signals to designate switches (e.g., assign converters to control groups) and configure assignable switches in the switch 936. The remote command signal can be transmitted to a supervisory channel of wavelength division multiplexed information transmitted on corresponding selected optical fiber pairs in each of the first, second, and third submarine optical fiber cables. The remote command signal can further instruct designated optical fiber pairs to be grouped together in a control group.

[0078] The logic circuit system 942 may be a processor that responds to remote command signals and other signals (e.g., status queries). The logic circuit system 942 may be implemented using an integrated circuit (IC), an application specific IC (ASIC), a field programmable array (FPGA), and / or a programmable logic device (PLD).

[0079] The memory 944 may store program code executable by the logic circuit system 942 and data structures (eg, look-up tables) for configuring the branching units 904 including the switches 936 and the ROADMs 906 .

[0080] The electrical-to-optical circuit system 952 is operable to switch any optical signal to an electrical signal, and vice versa. For example, the supervisory channel mentioned above may be an optical channel, and the command signal may be an optical signal that is switched to a corresponding electrical signal by the logic circuit 942.

[0081] The controller 902 further includes a control connection 948 for each corresponding reconfigurable optical add / drop multiplexer (ROADM) 906, which may be one of many ROADMs used in the system. For example, adding a ROADM to all or some of the input legs can provide higher granularity spectrum allocation between Site A, Site B, and Site C. The control connection 950 enables the controller 902 to control the operation of each corresponding ROADM (e.g., 906) of the plurality of ROADMs based on remote command signals. The controller 902 can receive remote command signals (and response signals) via the bus 946 and the control connection 948 at dedicated optical frequencies within corresponding optical fiber pairs of the cables 901, 903, and / or 905. Additionally or alternatively, the command signal 954 can be received via another cable or transmission method. Although ROADM 906 is shown accessing optical fiber pairs 908 and 910 from Site A and connecting to branching unit 904 via optical fiber pairs 920 and 922, a ROADM may be used to access some or all of the optical fiber pairs in each leg. For example, multiple ROADMs may be used as shown in FIG. 8, or a single ROADM may be configured to access all of the optical fiber pairs in the cable.

[0082] The controller 902 can be located outside the branching unit 904 or inside the branching unit 904. Similarly, the ROADM 906 can be located outside the branching unit 904 or inside the branching unit 904.

[0083] The architecture described herein is used for all bidirectional optical fiber pairs for bidirectional communication services. In alternative embodiments, it can also be used based on a single optical fiber and other applications (e.g., undersea scientific applications or unidirectional data acquisition from sensors).

[0084] Several examples of the present disclosure have been described above. However, it should be clearly pointed out that the present disclosure is not limited to these examples, and additions and modifications to the contents expressly described herein are intended to be included within the scope of the disclosed examples. Furthermore, it should be understood that the various exemplary features described herein are not mutually exclusive and can exist in various combinations and permutations, even if these combinations or permutations are not set forth herein, without departing from the spirit and scope of the disclosed examples. In fact, those skilled in the art may conceive of variations, modifications, and other embodiments of the contents described herein without departing from the spirit and scope of the disclosed examples. Thereby, the disclosed examples should not be defined solely by the preceding illustrative description.

[0085] It should be emphasized that the Abstract of the Disclosure is provided to allow the reader to quickly grasp the nature of the technical disclosure. With this understanding, it is submitted that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the preceding Detailed Description, various features are grouped together in a single example to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the example sought to be protected requires more features than are expressly recited in each claim. To the contrary, as reflected in the following claims, inventive subject matter encompasses fewer than all features of a single disclosed example. Accordingly, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate example. In the appended claims, the terms "including" and "in which" are used as the plain English equivalents of the corresponding terms "comprising" and "wherein," respectively. Furthermore, the terms "first," "second," "third," etc. are used merely as labels and are not intended to impose digital requirements on their subject matter.

[0086] The foregoing description of examples has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Numerous modifications and variations are possible from this disclosure. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the appended claims. Future filed applications claiming priority to this application may claim protection for the disclosed subject matter differently and may generally include any set or more of limitations as differently disclosed or otherwise set forth herein.

Claims

1. selecting, using at least one processor, one or more fiber pairs of a plurality of fiber pairs in one or more submarine cables for routing at least one transmission, the one or more submarine cables connecting one or more transmission sites; using the at least one processor to assign one or more optical switches to each selected fiber pair of the one or more selected fiber pairs; using the at least one processor to form one or more dedicated optical paths using the selected one or more fiber pairs and the assigned one or more optical switches; using the at least one processor to transmit the at least one transmission between the one or more transmission sites using the one or more formed dedicated optical paths; 1. A computer-implemented method comprising:

2. The computer-implemented method of claim 1 , wherein the selecting step comprises receiving a remote command identifying the one or more fiber-pairs for routing the at least one transmission.

3. The computer-implemented method of claim 1 or 2, wherein the one or more transmission sites include a first transmission site, a second transmission site, and a third transmission site.

4. 4. The computer-implemented method of claim 3, wherein a branching unit is configured to be coupled to the first transmission site, the second transmission site, and the third transmission site, the branching unit including one or more optical switches.

5. The one or more submarine cables one or more first submarine cables coupled to the first transmission site and the branching unit, the first submarine cables including one or more first fiber pairs of the plurality of fiber pairs coupled to one or more optical switches of the branching unit; one or more second submarine cables coupled to the second transmission site and the branching unit, the second submarine cables including one or more second fiber pairs of the plurality of fiber pairs coupled to one or more optical switches of the branching unit; one or more third submarine cables coupled to the third transmission site and the branching unit, the third submarine cables including one or more third fiber pairs of the plurality of fiber pairs coupled to one or more optical switches of the branching unit; The computer-implemented method of claim 4 , comprising:

6. 6. The computer-implemented method of claim 5, wherein the selecting step comprises selecting two fiber pairs within each submarine cable of the one or more submarine cables for routing the at least one transmission.

7. The selecting step comprises: a first fiber pair and a second fiber pair of the plurality of fiber pairs in the one or more first submarine cables; a third fiber pair and a fourth fiber pair of the plurality of fiber pairs in the one or more second submarine cables; 7. The computer-implemented method of claim 6, further comprising selecting a fifth fiber pair and a sixth fiber pair of the plurality of fiber pairs in the one or more third submarine cables for routing the at least one transmission.

8. The allocating step further comprises: a first optical switch and a second optical switch among the one or more optical switches to the first fiber pair and the second fiber pair; a third optical switch and a fourth optical switch among the one or more optical switches to the third fiber pair and the fourth fiber pair; 8. The computer-implemented method of claim 7, further comprising assigning a fifth optical switch and a sixth optical switch of the one or more optical switches to the fifth fiber pair and the sixth fiber pair for routing the at least one transmission.

9. 9. The computer-implemented method of claim 8, wherein the one or more dedicated optical paths include at least one optical path between at least one pair of at least one of the first optical switch, the second optical switch, the third optical switch, the fourth optical switch, the fifth optical switch, and the sixth optical switch.

10. 10. The computer-implemented method of claim 1, wherein the transmitting step includes linking at least two of the one or more transmission sites using the one or more dedicated optical paths while at least one of the one or more transmission sites is disconnected.

11. a branching unit configured to be coupled to one or more transmission sites, the branching unit including one or more optical switches; at least one controller communicatively coupled to the branching unit; at least one processor; and at least one non-transitory storage medium storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations, the operations comprising: selecting one or more fiber pairs of a plurality of fiber pairs in one or more submarine cables for routing at least one transmission, the one or more submarine cables connecting the one or more transmission sites; assigning the one or more optical switches to each selected fiber pair of the one or more selected fiber pairs; forming one or more dedicated optical paths using the one or more selected fiber pairs and the one or more assigned optical switches; transmitting the at least one transmission between the one or more transmission sites using the one or more formed dedicated optical paths; Including, the system.

12. The system of claim 11 , wherein the selecting step comprises receiving a remote command identifying the one or more fiber-pairs for routing the at least one transmission.

13. 13. The system of claim 11 or 12, wherein the one or more transmission sites include a first transmission site, a second transmission site, and a third transmission site.

14. The one or more submarine cables one or more first submarine cables coupled to the first transmission site and the branching unit, the first submarine cables including one or more first fiber pairs of the plurality of fiber pairs coupled to one or more optical switches of the branching unit; one or more second submarine cables coupled to the second transmission site and the branching unit, the second submarine cables including one or more second fiber pairs of the plurality of fiber pairs coupled to one or more optical switches of the branching unit; one or more third submarine cables coupled to the third transmission site and the branching unit, the third submarine cables including one or more third fiber pairs of the plurality of fiber pairs coupled to one or more optical switches of the branching unit; The system of claim 13 , comprising:

15. 15. The system of claim 14, wherein said selecting comprises selecting two fiber pairs within each submarine cable of said one or more submarine cables for routing said at least one transmission.

16. The selecting step comprises: a first fiber pair and a second fiber pair of the plurality of fiber pairs in the one or more first submarine cables; a third fiber pair and a fourth fiber pair of the plurality of fiber pairs in the one or more second submarine cables; 16. The system of claim 15, further comprising selecting a fifth fiber pair and a sixth fiber pair of the plurality of fiber pairs in the one or more third submarine cables for routing the at least one transmission.

17. The allocating step further comprises: a first optical switch and a second optical switch among the one or more optical switches to the first fiber pair and the second fiber pair; a third optical switch and a fourth optical switch among the one or more optical switches to the third fiber pair and the fourth fiber pair; 17. The system of claim 16, further comprising assigning a fifth optical switch and a sixth optical switch of the one or more optical switches to the fifth fiber pair and the sixth fiber pair for routing the at least one transmission.

18. 20. The system of claim 17, wherein the one or more dedicated optical paths include at least one optical path between at least one pair of at least one of the first optical switch, the second optical switch, the third optical switch, the fourth optical switch, the fifth optical switch, and the sixth optical switch.

19. 19. The system of claim 11, wherein the transmitting step includes linking at least two of the one or more transmission sites using the one or more dedicated optical paths while at least one of the one or more transmission sites is disconnected.

20. 1. A computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform operations, the operations comprising: selecting one or more fiber pairs of a plurality of fiber pairs in one or more submarine cables for routing at least one transmission, the one or more submarine cables connecting one or more transmission sites; assigning one or more optical switches to each selected fiber pair of the one or more selected fiber pairs; forming one or more dedicated optical paths using the one or more selected fiber pairs and the one or more assigned optical switches; transmitting the at least one transmission between the one or more transmission sites using the one or more formed dedicated optical paths; a computer program comprising:

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