Pairwise routes between three undersea fiber optic cables

Abstract

An undersea fiber optic cable routing architecture includes a branching unit coupled to three trunk cables that is capable of switching individual fibers in each fiber pair within the cable to either of the other two cables. The branching unit includes a plurality of optical switches and a controller for receiving a remote command signal and configuring the optical switches in accordance with the remote command signal.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 002,981, filed on March 31, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to the field of submarine communication networks, and more particularly to a submarine cable branching node with fiber pair conversion. Background Art

[0004] Submarine fiber optic cables are laid on the seabed or ocean floor between land-based terminals to carry optical signals over long stretches of ocean. Fiber optic cables typically include several fiber pairs and other components, such as strength members, power conductors, electrical insulators, and protective shields. The optical fibers can be single-core / mode fibers or multimode / core fibers. A first fiber of a fiber pair can be coupled in a system to communicate signals over the cable in a first direction, and a second fiber of the fiber pair can be configured to communicate signals over the cable in a second direction, opposite to the first direction, to support bidirectional communication.

[0005] In a branched submarine optical communication system, a trunk cable may extend between a first land-based trunk terminal and a second land-based 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 be connected to a branch cable that terminates at a transmitting and / or receiving land-based branch terminal. The branch cable may include multiple branch cable segments coupled between optical amplifiers for amplifying optical signals. Summary of the Invention

[0006] In one aspect, a submarine fiber optic cable routing system is provided. The submarine fiber optic cable routing system includes a branching unit coupled to three fiber optic cables. Each fiber optic cable has multiple fiber pairs. The branching unit may include multiple switches for each fiber pair. The multiple switches are configurable so that a fiber pair from any one of the three fiber optic cables can be switched to allow routing to any one of the other two fiber optic cables. A controller is operable to receive a remote command signal and configure the multiple switches as directed by the received remote command signal.

[0007] In another aspect, a submarine fiber optic cable routing system is provided, the submarine fiber optic cable routing system including a first submarine fiber optic cable, a second submarine fiber optic cable, and a third submarine fiber optic cable, and a branching unit. Each of the first submarine fiber optic cable, the second submarine fiber optic cable, and the third submarine fiber optic cable includes a plurality of fiber pairs. The branching unit can be configured to be coupled to each of the first submarine fiber optic cable, the second submarine fiber optic cable, and the third submarine fiber optic cable. The branching unit includes a first set of allocable transponders, a second set of allocable transponders, a third set of allocable transponders, a plurality of optical pathways, and a controller. The first set of allocable transponders can be configured to be optically coupled to the plurality of fiber pairs in the first submarine fiber optic cable, where each allocable transponder in the first set is coupled to a respective fiber pair in the first fiber optic cable. The second set of allocable transponders can be configured to be optically coupled to the plurality of fiber pairs in the second submarine fiber optic cable, and the third set of allocable transponders can be configured to be optically coupled to the third submarine fiber optic cable. Each allocable transponder in the second set is coupled to a respective fiber pair in the second fiber optic cable, and each allocable transponder in the third set is coupled to a respective fiber pair in the third fiber optic cable. The optical pathways are coupled to respective allocable transponders in each of the first set of allocable transponders, the second set of allocable transponders, and the third set of allocable transponders. The controller can be coupled to each respective allocable transponder in each of the first set of allocable transponders, the second set of allocable transponders, and the third set of allocable transponders, where the controller is operable to allocate respective first set allocable transponders from the first set to respective second set allocable transponders and to respective third set allocable transponders. BRIEF DESCRIPTION OF DRAWINGS

[0008] In the drawings, like reference numerals refer to like parts throughout the various views. In the following description, various embodiments of the present disclosure are described with reference to the following drawings, in which:

[0009] Figure 1 is a schematic diagram illustrating an example branching optical communication system.

[0010] Figure 2 is a diagram illustrating a branching unit between three submarine cables, where each fiber pair has a dedicated fiber transposition configuration.

[0011] Figure 3 is a diagram of fiber pair transposition connectivity between three sites, showing transposition connections between various fiber pairs in each cable.

[0012] Figure 4 is a diagram of an alternative embodiment of the present invention linking fiber pairs in each cable together into larger, more flexible reconfigurable groups.

[0013] Figure 5It shows Figure 4 Figure 2 shows a diagram of the links between the two fiber pairs in each of the three cables in the conversion configuration shown in FIG.

[0014] Figure 6 States of an example branching unit including additional reconfigurable components coupled to a cable input into an example branching unit architecture are shown.

[0015] Figure 7 Another example of a configuration of a branching unit architecture is shown.

[0016] Figure 8 Yet another example of a configuration of a branching unit architecture is shown.

[0017] Figure 9 An example of a branching unit control configuration in a submarine optical fiber cable routing system is shown. DETAILED DESCRIPTION

[0018] The systems and devices according to the present disclosure will now be described more fully below with reference to the accompanying drawings, in which one or more embodiments are shown. These systems and devices can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the disclosure will be comprehensive and complete and fully convey the scope of the methods and devices to those skilled in the art. Each of the systems, devices, and methods disclosed herein provides one or more advantages over conventional systems, components, and methods.

[0019] Submarine cables are typically implemented using a trunk and branch architecture, as described above. The typical connection architecture designates two cables as "trunk" cables and a third cable as a "branch" cable. In the network unit, fiber converters on each trunk fiber pair are configured so that individual trunk fiber pairs connect to or bypass a corresponding set of branch fiber pairs. In the new configuration described herein, there is no trunk and branch designation.

[0020] The disclosed subject matter provides the ability to bring three trunk cables together by providing a new switching architecture that can be used to provide reconfigurable routing flexibility between the fiber pairs in all three cables. The new switching architecture allows for connecting "any two of the three trunk cables" on a per-fiber, per-fiber-pair, or per-group basis. Additional features will be apparent to those skilled in the art from the following figures, description, and claims.

[0021] The distributable converters described herein can be configured to connect any two of three fiber pairs, with one fiber pair from each of three cables. Fiber pair selectivity can be provided for anywhere between one "three" fiber pair (e.g., 1×1×1) to N three fiber pairs (e.g., N×N×N), where N is the fiber pair count of the cable with the lowest number of fiber pairs.

[0022] Figure 1 An exemplary branched optical communication system 100 is shown. For ease of explanation, system 100 has been depicted in a highly simplified form. 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 via a branch cable 162. In some embodiments, system 100 can be configured as a long-haul system, e.g., having a length exceeding approximately 600 km between at least two of the terminals, spanning a body of water, such as an ocean. Trunk cable 112 can thus span between beach platforms.

[0023] Both the trunk cable 112 and the branch cable 162 can include multiple fiber optic 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 can include one or more fiber optic cable segments and one or more repeaters 170. Each segment of the fiber optic cable can be of a known configuration, including multiple optical fiber pairs, one or more layers of strength members, electrical power conductors, insulation, and an armor covering. The optical fiber pairs and power conductors of the fiber optic cable are covered and protected within the cable by the armor covering, members, and protective covering.

[0024] Thus, the system 100 can be configured to provide bidirectional communication of optical signals between any of the terminals 110, 120, 160. For ease of explanation, the description herein may refer to transmission from one terminal to another. However, it should be understood that the system 100 can be configured for bidirectional or unidirectional communication between any number of the terminals 110, 120, 160.

[0025] At least one fiber pair switching branching unit (FPS-BU) 130 can be coupled to a trunk cable between trunk terminals 110, 120. As will be described in greater detail below, 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, FPS-BU 130 is configured to allow remote and selectively controllable routing of two or more trunk cable fibers to a lesser number of branch cable fiber pairs. Although FPS-BU 130 is shown in FIG. 1 as a single element, it will be appreciated that the functionality of FPS-BU 130 can be integrated into a single element disposed in a single housing, or portions of the functionality can be physically separated from one another, for example by several kilometers or by one or more water depths, to allow for retrieval of the elements from the ocean floor for independent repair or replacement from one another. Figure 1 Although FPS-BU 130 is shown in FIG. 1 as a single element, it will be appreciated that the functionality of FPS-BU 130 can be integrated into a single element disposed in a single housing, or portions of the functionality can be physically separated from one another, for example by several kilometers or by one or more water depths, to allow for retrieval of the elements from the ocean floor for independent repair or replacement from one another.

[0026] FPS-BU 130 can be associated with an optional wavelength management unit (WMU) unit 150 configured to provide selective wavelength filtering of signals on branch cable fiber pairs coupled to FPS-BU 130.

[0027] Figure 2 A first embodiment is shown, showing three cables 210, 212, and 224 connected at a branching unit 214 from three sites 202a, 202b, and 202c, respectively. The three sites 202a, 202b, and 202c can output information as optical signals for transmission over the respective cables 210, 212, and 224. Each cable 210, 212, or 224 has a number of fiber pairs, with each fiber pair having two fibers. For example, fiber pair 234 from submarine fiber optic cable 224 has one inbound fiber 238 to site 2 202b and one outbound fiber 236 from site 2 202b, which allows for bidirectional communication between sites 202a and 202b. For example, submarine fiber optic cable 210 has a fiber pair including inbound fiber 208 and outbound fiber 232.

[0028] Branching unit 214 can include a plurality of allocable switches 204, 206, 216, 218, 220, and 222, and a plurality of optical paths (such as 228 and 230) coupling the various allocable switches to one another. Branching unit 214 can be configured to allow remote and selectively controllable routing of fiber pairs in response to remote command signals. The remote command signals for configuring the switches can be transmitted, for example, on a supervisory channel of a wavelength division multiplexed signal transmitted on any of the three cables 210, 212, or 224. Branching unit 214 can include a controller 226 for extracting the remote command signals from the supervisory channel and for configuring the switches in response to the remote command signals. In alternative embodiments, the remote command signals can be transmitted to branching unit 214 by any known means, including, for example, transmitting the remote command signals on the fibers of the fiber pairs being converted (such as fiber 208 and fiber 232) and retrieved by controller 226.

[0029] Figure 2 Conversion of fiber pairs from each cable is shown. Figure 2 Embodiments of the present application are capable of routing individual fiber pairs within each of cables 210, 212, or 224. This embodiment shows one fiber pair from each of the three cables connected through an assembly of six 1x2 optical switches. However, switches having other ratios can also be used, such as 2x2 blocking, 2x2 non-blocking, or larger ratio switches.

[0030] To change the optical fiber path (e.g., from connecting site 202a to site 202c to connecting site 202a to site 202b), the optical switches in branching unit 214 for both fibers must be configured by controller 226. To establish the optical path for one fiber in the fiber pair, two of the three switches for one fiber are configured to couple to the correct switches. For example, one "headend" switch (such as switch 204) for incoming fiber 208 and one "selector" switch (such as switch 206) for coupling to outgoing fiber 236. Switch 206 can be a switch corresponding to switch 204, and switch 216 can be a switch corresponding to switch 220. The corresponding switch is an optically distributable switch in another cable that matches the direction of optical signal flow. In the example, both fibers of the fiber pair follow the same route between the sites, i.e., both fibers of the fiber pair (e.g., 208 and 232 of site 202a) are switched together (e.g., using switches 204 and 220) to couple to corresponding fibers 236 and 238 of fiber pair 234 of cable 224. When the switching described above is complete, optical signal transmission from converters 218 and 222 of cable 212 to converters 204 and 220 of cable 210 is no longer enabled. Additionally, optical signal transmission from converters 218 and 222 of cable 212 to converters 206 and 216 of cable 224 is no longer enabled. The foregoing description describes the formation of switching triangles between converters 204, 206, and 218 of respective cables 210, 212, and 224, and the corresponding switching triangles of switches 220, 216, and 222.

[0031] When one submarine fiber optic cable has fewer fiber pairs than other submarine fiber optic cables, the number of fiber pairs supported is limited to that number of fiber pairs. For example, if two of three fiber optic cables have 16 fiber pairs and the third fiber optic cable has only 6 fiber pairs, only 6 fiber pairs from each of the three cables are configured in a "two out of three" configuration.

[0032] Figure 3 An expansion of the switching of individual fiber pairs for switching between three submarine fiber optic cables is shown (e.g. Figure 2 shown), for example Figure 3 Each submarine fiber optic cable in has 16 fiber pairs. Submarine fiber optic cable routing system 300 may include sites 304, 306, and 308, submarine fiber optic cables 312, 314, and 316, and a configurable branching unit 310.

[0033] Sites 304, 306, and 308 may provide optical signals (not shown) containing information to be transmitted for further distribution or received from another corresponding site (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, electro-optical conversion equipment, optical amplifiers, repeaters, etc. Figure 2 Like the submarine fiber optic cables 210, 212, and 224, the submarine fiber optic cables 312, 314, and 316 include multiple optical fiber pairs.

[0034] Submarine fiber optic cables 312 , 314 , and 316 may be optically coupled to respective sites 304 , 306 , and 308 at first ends and coupled to branching unit 310 at second ends.

[0035] The configurable branching unit 310 may include a plurality of optical switches as assignable switches, a plurality of optical pathways 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 pathways 320, and the controller 322. The controller 322 may optionally be located within the housing 324 of the configurable branching unit 310.

[0036] exist Figure 3 In the example of FIG, submarine fiber optic cable 312 includes 16 fiber pairs (such as fiber pair 326) that are coupled to a distributable switch (such as 302) in a plurality of distributable switches in configurable branching unit 310. Figure 3 In the example shown there are 16 optically distributable switches 302 for each fiber pair, but in reality there are 32 optically distributable switches 302, i.e., one optically distributable switch for the inbound fiber and one optically distributable switch for the outbound fiber for each of the 16 fiber pairs shown in fiber optic cables 312, 314, and 316.

[0037] In the exemplary configurable branching unit 310 , one optical fiber from each of the cables 312 , 314 , and 316 may be distributed by the controller 322 to a “switching triangle” 318 between the three cables 312 , 314 , and 316 . Figure 3 An example of a transition triangle 318 is shown as one of three examples of transition triangles shown, and those skilled in the art will recognize that a transition triangle may exist for each corresponding fiber pair from each cable 312 , 314 , and 316 .

[0038] The conversion triangle 318 represents the three possible connection paths for a group of each fiber pair in the configurable branching unit 310 (i.e., fiber pair 326 of the submarine fiber optic cable 312, fiber pair 328 of the submarine fiber optic cable 314, and fiber pair 330 of the submarine fiber optic cable 316). Only one side of the conversion triangle 318 is active at a time, forming a connection between two of the three sites. The other two sides of the conversion triangle 318 are broken at each vertex of the conversion triangle 318 by the respective optical switch 302.

[0039] Figure 2 And Figure 3 The various embodiments shown in FIGS. 1-3 provide novel optical conversion configurations in a submarine cable environment. The branching unit 214 and the configurable branching unit 310 can be configured to connect two of the three sites on each fiber pair. For each fiber pair, a first site (e.g., site 202a of FIG. 1 or site 304 of FIG. 3) can be connected to a second site (e.g., site 202b of FIG. 1 or site 306 of FIG. 3), while a third site (e.g., site 202c of FIG. 1 or site 308 of FIG. 3) is broken. Alternatively, the first site (e.g., site 202a of FIG. 1 or site 304 of FIG. 3) can be connected to the third site (e.g., site 202c of FIG. 1 or site 308 of FIG. 3), while the second site (e.g., site 202b of FIG. 1 or site 306 of FIG. 3) is broken. In another alternative, the second site (e.g., site 202b of FIG. 1 or site 306 of FIG. 3) can be connected to the third site (e.g., site 202c of FIG. 1 or site 308 of FIG. 3), while the first site (e.g., site 202a of FIG. 1 or site 304 of FIG. 3) is broken. Any "odd" number of remaining fiber pairs in any cable can be managed with a single fiber pair architecture, such as shown in the embodiments of FIGS. 4-6. Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3 Figure 2 Figure 3

[0040] Figure 4 ​​​​​​​​​​​​​​​​​​​​is a diagram of an alternative embodiment of the present invention that links the fiber pairs in each cable together into larger, more flexible, reconfigurable groups. In submarine fiber optic cable routing system 400, station 402, station 404, and station 406 are coupled to branching unit 408. Figure 4 In the example of , the selection group is expanded to include two fiber pairs in each corresponding cable 410, 412, and 414. Figure 4 In the example shown in FIG. 4 , controller 416 may have selected a group of two fiber pairs for conversion. Controller 416 is operable to designate any two fiber pairs in each of cables 410, 412, and 414 as part of the same selected group. For example, a remote command signal may be received instructing controller 416 which fiber pairs from the corresponding cables 410, 412, or 414 or from the corresponding sites 404, 402, and 406 to designate as part of the selected group for conversion.

[0041] In an example, a first fiber pair (i.e., site 402FP1) in site 402 and a second fiber pair (i.e., site 402FP2) in site 402 in cable 412 can be designated by controller 416 as part of a selected group. Fiber pairs (e.g., site 404FP1, site 404FP2, site 406FP1, and site 406FP2) in corresponding cables 410 and 414 can also be designated by controller 416 to complete the selected group. Once the selected group is designated, controller 416 can assign two optically distributable switches coupled to each designated fiber pair (e.g., site 402FP1, site 404FP1, and site 406FP1) to couple to each other via an optical pathway (shown by a dashed line). In an example, the two optically distributable switches coupled to each designated fiber pair (e.g., site 402FP1) in cable 412 can be coupled to a corresponding one or two sets of optically distributable switches coupled to the designated fiber pair (i.e., site 406FP1) in cable 414 via a dedicated optical pathway. Similarly, the two optically distributable switches coupled to each designated fiber pair (e.g., site 406FP1) of cable 414 can be coupled to a corresponding one or two sets of optically distributable switches coupled to the designated fiber pair (i.e., site 406FP1) of cable 410 via dedicated optical pathways.

[0042] Figure 4 The embodiment shown in FIG provides additional flexibility by allowing configurations with two connected fiber pairs per selected group. For example, two fiber pairs can be used to connect site 402 to site 404 in the event that site 406 is disconnected; two fiber pairs can be used to connect site 402 to site 406 in the event that site 404 is disconnected; or two fiber pairs can be used to connect site 404 to site 406 in the event that site 402 is disconnected.

[0043] Figure 5 Shown in such Figure 4 FIG2 illustrates an alternative view of the links between two fiber pairs in each of the three cables in the converter configuration shown in FIG2 . In this example, submarine fiber optic cable routing architecture 500 includes cables 502, 504, and 506 and a branching unit 520. In this example, each of cables 502, 504, and 506 includes 16 fiber pairs (inbound and outbound fibers). As in the previous example, branching unit 520 has 32 corresponding optically distributable optical switches to couple to the corresponding inbound and outbound fibers. In this example, the controller has designated the outermost fiber pairs to be coupled to each other. The designated couplings connect cable 502FP1 to cable 504FP1 to cable 506FP1 and cable 502FP2 to cable 504FP2 to cable 506F2 from respective cables 502, 504, and 506 to each other. The controller also assigns optically distributable switches to route the designated fiber pairs based on the designated couplings. For example, the controller can assign optically distributable converter 508 (of cable 502) to corresponding optically distributable converter 510 (of cable 504) and corresponding optically distributable converter 514 (of cable 506). The controller can also assign optically distributable converter 516 (of cable 502) to corresponding optically distributable converter 512 (of cable 504) and corresponding optically distributable converter 518 (of cable 506). Because each optically distributable converter includes a converter for coupling to each optical fiber of a corresponding optical fiber pair, bidirectional operation is achieved.

[0044] Branching unit 520 includes multiple optical pathways, such as 522, 524, 526, 528, 530, and 532, interconnecting each of optically distributable switches 508 through 518. Each optically distributable switch is coupled to two optical pathways. For example, optically distributable switch 518 is optically coupled to optically distributable switch 516 via optical pathway 530 and to optically distributable switch 510 via optical pathway 524. Similarly, optically distributable switch 516 is optically coupled to optically distributable switch 512 via optical pathway 526. As in the previous example, only one of the two optical pathways is active at a given time. Based on which optical pathway is active, the optically distributable switches can be controlled to place branching unit 520 in one of five different states.

[0045] Figure 6Example states of fiber pairs in a branching unit are shown. In the example shown, for ease of illustration and explanation, each site cable is shown as providing two fiber pairs to branching unit 600. Each fiber pair includes two optical fibers, an inbound fiber and an outbound fiber. Branching unit 600 is configured with one optically distributable converter for each fiber in the fiber pair. In branching unit 600, the first fiber pair in site 1 is coupled to two optically distributable converters, represented by optically distributable converter 602, and the second fiber pair is coupled to two other optically distributable converters, represented by optically distributable converter 604. Similarly, the first fiber pair in site 2 is coupled to two optically distributable converters, represented by optically distributable converter 606, and the second fiber pair is coupled to two other optically distributable converters, represented by optically distributable converter 608. Furthermore, the first fiber pair in site 3 is coupled to two optically distributable converters, represented by optically distributable converter 610, and the second fiber pair is coupled to two other optically distributable converters, represented by optically distributable converter 612.

[0046] A controller (not shown in this example) can control the status of the fiber pairs designated for routing in the branching unit 600 in response to the remote command signal by sending instructions to the corresponding optical distributable converters of the fiber pairs designated for routing. In response to the remote command signal, the branching unit 600 is then positioned.

[0047] In state 1, the respective optical distributable switches 602 and 604 at site 1 in the branching unit 600 are configured to transmit optical signals from site 1 to the corresponding optical distributable switches 612 and 610 at site 3 (as shown by the solid lines). In state 1, the optical paths between the optical distributable switches 602 and 604 at site 1 and the optical distributable switches 608 and 606 at site 2 are inactive (as shown by the dashed lines).

[0048] In State 2, the individual optical distributable switches of the branching unit 600 are configured to transmit optical signals from the optical distributable switches 606 and 608 at Site 2 to the corresponding optical distributable switches 612 and 610 at Site 2. In State 2, the optical pathways between the optical distributable switches 606 and 608 at Site 2 and the corresponding optical distributable switches 604 and 602 at Site 1, as well as the optical pathways between the optical distributable switches 602 and 604 at Site 1 and the corresponding optical distributable switches 612 and 610 at Site 3 are all shown as being inactive (as indicated by the dashed lines).

[0049] In State 3, the individual optical distributable switches of the branching unit 600 are configured to transmit optical signals from the optical distributable switches 606 and 608 at Site 2 to the corresponding optical distributable switches 604 and 602 at Site 1. In State 2, the optical pathways between the optical distributable switches 606 and 608 at Site 2 and the corresponding optical distributable switches 612 and 610 at Site 3, as well as the optical pathways between the optical distributable switches 602 and 604 at Site 1 and the corresponding optical distributable switches 612 and 610 at Site 3, are all shown as being inactive (as indicated by the dashed lines).

[0050] States 1 through 3 are states in which two fiber pairs from a first site are routed to two fiber pairs at a second site. However, one of the additional improvements and advantages of the disclosed routing architecture and submarine fiber optic cable routing system is the ability to designate and route a first fiber pair from a first site to a second site and a second fiber pair from the first site to a third site. The examples of States 4 and 5 illustrate these advantageous configurations.

[0051] In state 4, the first fiber pair of site 1 coupled to optical distributable switch 602 is routed to the corresponding first fiber pair of site 3 by being coupled to optical distributable switch 612, the second fiber pair of site 1 coupled to optical distributable switch 604 is routed to the corresponding first fiber pair of site 2 by being coupled to optical distributable switch 606, and the second fiber pair of site 2 coupled to optical distributable switch 608 is routed to the corresponding second fiber pair of site 3 by being coupled to optical distributable switch 610.

[0052] State 5 provides a variation of State 4 that demonstrates the flexibility provided to the controller in designating individual fiber pairs for routing. In State 5, the first fiber pair at site 1 coupled to optically distributable switch 602 is routed to the corresponding first fiber pair at site 2 via coupling to optically distributable switch 608, the second fiber pair at site 1 coupled to optically distributable switch 604 is routed to the corresponding first fiber pair at site 3 via coupling to optically distributable switch 610, and the second fiber pair at site 2 coupled to optically distributable switch 606 is routed to the corresponding second fiber pair at site 3 via coupling to optically distributable switch 612.

[0053] The ability to specify the routing of individual fiber pairs enables the controller to respond to remote commands specifying any number of individual fiber pairs for routing as a group. For example, groups of 2, 5, 15, 24, and up to N are possible, where N is the minimum number of fiber pairs in the cable. This routing capability improves the optical signal distribution system's ability to respond to changes in demand, equipment failures, and outages.

[0054] The advantages of the disclosed routing architecture and submarine fiber optic cable routing system shown in and described with respect to the preceding examples may be further improved by incorporating additional conversion capabilities as shown and described in the following examples.

[0055] Figure 7 Another example of a configuration of a branching unit incorporating additional spectrum routing devices is shown.

[0056] exist Figure 7 In the example of FIG, the 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 from a third site 714, and a branching unit 722. Each of the first submarine optical fiber cable 716, the second submarine optical fiber cable 718, and the third submarine optical fiber cable 720 includes a plurality of optical fiber pairs. In this example, the number of optical fiber pairs is 16, but the number of optical fiber pairs can also be 3, 8, 9, 12, 24, etc.

[0057] The branching unit 722 can be configured to couple to each of the first submarine optical fiber cable 716, the second submarine optical fiber cable 718, and the third submarine optical fiber cable 720 to enable routing (or "branching") of optical signals from one of the optical fiber cables to another. The branching unit 722 can also include a first set of optically distributable converters 724 configured to optically couple to a plurality of optical fiber pairs in the first submarine optical fiber cable 716, a second set of optically distributable converters 726 configured to optically couple to a plurality of optical fiber pairs in the second submarine optical fiber cable 718, and a third set of optically distributable converters 728 configured to optically couple to a plurality of optical fiber pairs in the third submarine optical fiber cable 720. Each of the first set of optically distributable converters 724 can be coupled to a corresponding optical fiber pair in the first optical fiber cable 716. Similarly, each of the second set of optically distributable converters 726 can be coupled to a corresponding optical fiber pair in the second optical fiber cable 718, and each of the third set of optically distributable converters 728 can be coupled to a corresponding optical fiber pair in the third optical fiber cable 720.

[0058] The branching unit 722 also includes a plurality of optical pathways (collectively designated 702) coupling the respective allocable converters in the first group 724, the second group 726, and the third group 728 of allocable converters to each other.

[0059] The controller 730 may be coupled to each respective allocable converter in each of the first group of allocable converters 724, the second group of allocable converters 726, and the third group of allocable converters 728. The controller 730 may be operable to allocate a respective first group of allocable converters from the first group of allocable converters 724 to a respective second group of allocable converters in the second group 726 and a respective third group of allocable converters in the third group 728.

[0060] In the example system 700, the number of designated fiber pairs for conversion may be 16 x 16 x 16. For example, the controller 730 may be operable to assign corresponding optical assignable switches in the first group of assignable switches 724 to corresponding assignable switches in each of the second group of assignable switches 726 and the third group of assignable switches 728. Based on the assignments to the corresponding assignable switches in the first, second, and third groups, a "conversion triangle" (such as 727) may be formed.

[0061] The optical cable routing system may further include a plurality of ROADMs 704, 706, and 708 coupled to selected optical fiber pairs in each of the first submarine optical fiber cable (716), the second submarine optical fiber cable (718), and the third submarine optical fiber cable (720). Each respective reconfigurable optical add / drop multiplexer in the plurality of reconfigurable optical add / drop multiplexers is coupled to the respective selected optical fiber pairs before the respective selected optical fiber pairs are coupled to the respective distributable switches. For example, the respective 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 optical distributable switches 728.

[0062] exist Figure 7An additional spectrum routing device referenced in the description of may be a reconfigurable optical add-drop multiplexer (ROADM) incorporated before the optically distributable switch of the branching unit. As previously mentioned, submarine fiber optic cables 716, 718, and 720 carry optical signals transmitted at different optical wavelengths. Different optical fibers in the cables (such as inbound fibers) may carry light of different wavelengths. The ROADM is configured to traverse multiple optical fibers of two types, where the types refer to inbound fibers of one type and outbound fibers of another type. The ROADM can be controlled by a controller (shown in other examples) that also controls the branching unit. The ROADM can be configured to combine a first designated wavelength group from one input (e.g., a first inbound fiber) with a second designated wavelength group of different wavelengths from another input (e.g., a second inbound fiber) to allow the first and second designated wavelength groups to share an inbound fiber pair. For example, once combined, the combined wavelengths may share the first inbound fiber, the second inbound fiber, or both the first inbound fiber and the second inbound fiber.

[0063] In reference Figure 6 In the example of the state and ROADM, a ROADM such as 706 can be installed on two fiber pairs of cable 718 at the second site 712. The controller 730 can receive a remote command signal specifying two fiber pairs to be coupled to the ROADM 706 for conversion. The corresponding two fiber pairs coupled to the ROADM 706 can be configured as follows: Figure 6As shown in State 4 of FIG. , this enables controller 730 to direct the optical signal in one of the two fiber pairs coupled to ROADM 706 from second site 712 to first site 710. The optical signal in the other fiber pair coupled to ROADM 706 can be directed to third site 714. The fiber pair in first site 710 can be coupled to the fiber pair in third site 714. ROADM 706 allows two fiber pairs to share the optical wavelength spectrum transmitted through the two shared fiber pairs. In the event that the fiber pair coupled to ROADM 706 carries a larger portion of the optical wavelength spectrum from second site 712, ROADM 706 can share the spectrum, but can also signal to controller 730 that the state of the fiber pair should be transitioned from State 4 (1FP on all paths) to State 2. In State 2, the two fiber pairs coupled to ROADM 706 and the corresponding assignable switches 728 are designated for conversion to handle the larger portion of the spectrum. In response to the designation for the switch, controller 730 issues a control signal to reallocate the corresponding distributable switches in the second set of distributable switches 726 coupled to the two fiber pairs to be switched to State 2. By switching to State 2, the shared optical wavelength spectrum is distributed and delivered to the third site. Alternatively, returning to when the corresponding fiber pairs were configured in State 2, ROADM 706 can determine, by monitoring the corresponding fiber pairs coupled to ROADM 706 that convey optical signals to and from first site 710, that the fiber pairs from first site 710 are carrying a greater portion of the optical wavelength spectrum. Consequently, ROADM 706 can forward this information to controller 730, which can cause the corresponding distributable switches of the fiber pairs to change to State 1, wherein the fiber pairs from first site 710 previously coupled to ROADM 706 are now switched to couple one of the fiber pairs from first site 710 to the distributable switches that direct the optical signals to third site 714.

[0064] Figure 8 Yet another example of a configuration of a branching unit architecture is shown. The configurable branching unit 800 provides an illustration of the fiber pair selectivity of the concept implementing anywhere between one "triplet" of fiber pairs (e.g., 1×1×1) to N triplets of fiber pairs (e.g., N×N×N), where N is the fiber pair count of the fiber optic cable having the lowest number of fiber pairs.

[0065] The configurable branching unit 800 may include three sites (site 1 834, site 2 836, and site 3 838), and respective submarine fiber optic cables having a plurality of fiber pairs are coupled from the sites to the branching unit 842. The number of fiber pairs in each of the cables shown is 16, but a different number of fiber pairs may be used. Within or connected to each submarine fiber optic cable is a ROADM coupled to each fiber pair (as shown in FIG. Figure 7 While ROADMs may typically be configured on two fiber pairs serving one of the three sites, other configurations are also contemplated. For example, a cable from site 1 834 may have ROADMs R1 820, R2 818, R3 816, and R4 808, with each ROADM coupled to a corresponding fiber pair (e.g., two fiber pairs, etc.) of the 16 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 fiber pair (such as 2 fiber pairs, etc.) of the 16 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 fiber pair (such as 2 fiber pairs, etc.) of the 16 fiber pairs in the cable from site 3 838.

[0066] The branching unit 842 is similar to the previously described examples in terms of the number of optically distributable converters and optical pathways, as well as responsiveness to commands from the controller 840. For example, each cable has a corresponding optical fiber pair coupled to a corresponding distributable converter in a set of distributable converters from the sites in the branching unit 842. For example, the optical fiber pairs of the cable from site 1 834 are coupled to a set of distributable converters 844 in the branching unit 842, the optical fiber pairs of the cable from site 2 836 are coupled to a set of distributable converters 846, and the optical fiber pairs of the cable from site 3 838 are coupled to a set of distributable converters 848.

[0067] As about Figure 7 As mentioned in the example, Figure 8In the example, controller 840 can also determine a state setting for a corresponding optical distributable converter in branching unit 842 for each cable coupled to site 1 834, site 2 836, and site 3 838. The controller can also be operable to, in response to a remote command signal, group together groups of distributable converters, where each group of distributable converters includes at least one converter coupled to a fiber pair that is also coupled to the ROADM. The controller can set a group state and can determine a state for each fiber pair based on the group state. An operational example may be helpful.

[0068] In an example operation, controller 840 may receive a remote command signal specifying fiber pairs to be switched, and which of the specified fiber pairs are to be grouped together into three groups. In response to the remote command signal, controller 840 may be operable to subdivide first group of allocable converters 844 into groups of first allocable converters and subdivide second group of allocable converters 846 into groups of second allocable converters, wherein the number of allocable converters in each of the groups of the second allocable converter states corresponds to the number of allocable converters in the groups of the first allocable converters. Controller 840 may also subdivide third group of allocable converters 848 into groups of third allocable converters, wherein the number of allocable converters in each of the groups of the third allocable converters corresponds to the number of allocable converters in each of the groups of the first allocable converters and the second allocable converters. Controller 840 may also be operable to assign corresponding groups of the first allocable converters to corresponding groups of the second and third allocable converters.

[0069] like Figure 8As shown, the controller 840 can subdivide the first group of allocable converters into a first group of four allocable converters, which can include those converters coupled to fiber pairs in cables from site 1 834 including ROADM R1 820. The controller can subdivide the allocable converters from the second group of allocable converters 846 and the third group of allocable converters 848 into groups including corresponding groups of four allocable converters. The controller 840 can place the group of four allocable converters from the first group of allocable converters 844 and the corresponding group of four allocable converters from the second group of allocable converters 846 and the third group of allocable converters 848 together in a control group (such as R1-4 x 4×4 802) that also includes the corresponding fiber pairs coupled to each cable of the corresponding ROADMs R1 820, R1 806, and R1 826. Similarly, the controller may generate control groups such as R2-4x4x4 810, which also includes a corresponding fiber pair for each cable coupled to the corresponding ROADMs R2 816, R2 828, and R2 824. The controller may generate control groups with different numbers of allocable converters, such as R3-2x2x2 812, which have a group of 2 allocable converters from each cable and include a corresponding fiber pair for each cable coupled to the corresponding ROADMs R3 818, R2 830, and R2 822. Another control group may be R4-6x6x6 814, which has a group of 6 allocable converters from each cable and includes a corresponding fiber pair for each cable coupled to the corresponding ROADMs R4 808, R4 832, and R8 804.

[0070] The generation of control groups may be limited by the number of allocable switches in the group. The group size may be based on a minimum number of fiber pairs in a corresponding one of the first submarine optical fiber cable, the second submarine optical fiber cable, and the third submarine optical fiber cable, and each corresponding group may have the same number of allocable switches.

[0071] Additionally, additional flexibility can be provided in the fiber pair routing between the three cables. Groups of more than one fiber pair per cable can be combined into flexible cross-pair routing groups. Switch types other than "one-to-two" (connecting between one input / output port and two output / input ports) can be used for more complex configurations, such as 2x2 blocking, 2x2 non-blocking, or larger ratio switches.

[0072] Alternative optical devices can be used for routing, such as wavelength selective switch filters. The direction of fiber traffic propagation on each fiber can remain the same in all configuration states, or can be reversed in some configurations. For all configurations, a configuration can be provided that maintains two fibers coupled into a fiber pair. Additionally or alternatively, the allocation of fibers within the cable into fiber pairs can be different in different configuration states. This functionality can be implemented with alternative methods, including higher order switching, and is not limited by the architecture shown.

[0073] Figure 9 An example of branch unit control configuration in a submarine fiber optic cable routing system is shown.

[0074] A submarine fiber optic cable routing system 900 can include a controller 902 and a branch unit 904. The branch unit 904 can be configured to couple to a plurality of fiber optic cables. The number of fiber optic cables can be three, such as cable 901 from site A, cable 903 from site B, and cable 905 from site C. Each of the three fiber optic cables 901, 903, and 905 can include a number N of fiber pairs, such as 914, 924, and 956, where N is 2, 4, 5, 12, 16, 24, etc. Note that in the branch unit 904, it can be provisioned to receive a different number of fiber pairs in each cable. Each of the plurality of fiber pairs in the first submarine fiber optic cable 901 includes an outbound fiber (such as 938) for outputting an optical signal from a first site (e.g., site A), and an inbound fiber 940 that delivers an optical signal to the first site (i.e., site A). Likewise, each of the plurality of fiber pairs in the second submarine fiber optic cable 903 includes an outbound fiber for outputting an optical signal from a second site (e.g., site B), and an inbound fiber that delivers an optical signal to the second site, and each of the plurality of fiber pairs in the third submarine fiber optic cable 905 also includes an outbound fiber for outputting an optical signal from a third site (e.g., site C), and an inbound fiber that delivers an optical signal to the third site.

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

[0076] The branching unit 904 may include a bus 946 and converters 936 for the cables. The respective optical fiber pairs of cables 901, 903, and 905 may be coupled to respective optically distributable converters 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 monitoring channel over which remote command signals may be transmitted. The bus 946 may be coupled to the respective converters, enabling the controller 902 to monitor the monitoring channels and also assign conversions to the respective converters 936 of the respective cables.

[0077] The controller 902 may include logic circuitry 942, memory 944, and electro-optical conversion circuitry 952. The controller 902 may receive a designation of an optical fiber pair to be converted in a remote command signal. The controller 902 may be coupled to a bus 946 of the branching unit 904 via a control connection 948, which may be an optical connection or an electrical connection. The control connection 948 enables the logic circuitry 942 to receive remote command signals and send control signals, make conversion designations (such as assigning converters to control groups), and configure the assignable converters in the converter 936. The remote command signal may be transmitted on a monitoring channel of a wavelength division multiplexed signal transmitted on a corresponding selected optical fiber pair in each of the first submarine optical fiber cable, the second submarine optical fiber cable, and the third submarine optical fiber cable. The remote command signal may also indicate that the specified optical fiber pairs are to be grouped together in a control group, such as Figure 8 Group R1 - 4x4x4.

[0078] The logic circuit system 942 may be a processor that responds to remote command signals and other signals (such as status queries, etc.) 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] Memory 944 may store programming code executable by logic circuitry 942 and data structures (such as lookup tables) that may be used to configure branching unit 904 , including switch 936 and ROADM 906 .

[0080] The electrical-to-optical conversion circuitry 952 is operable to convert any optical signal into an electrical signal, and vice versa. For example, the aforementioned monitoring channel may be an optical channel, and the command signal may be an optical signal converted into an electrical signal compatible with the logic circuit 942.

[0081] The controller 902 can also include a control connection 948 to each respective reconfigurable optical add-drop multiplexer (ROADM) 906, which can be one of many ROADMs used in the system. For example, a ROADM can be added on all or some of the input legs to provide higher granularity of spectrum allocation among site A, site B, and site C. The control connection 950 enables the controller 902 to control the operation of each respective ROADM (such as 906) of the plurality of ROADMs based on a remote command signal. The remote command signal (and response signal) can be received by the controller 902 via a dedicated optical frequency within the respective optical fiber pair of the cables 901, 903, and / or 905 via the bus 946 and control connection 948. Additionally or alternatively, the command signal 954 can be received by another cable or transmission method. While the ROADM 906 is shown as accessing the fiber pairs 908 and 910 from site A, and connecting to the branching unit 904 via fiber pairs 920 and 922, the ROADM can be used to access some or all of the fiber pairs on each leg. For example, multiple ROADMs can be used as shown in Figure 8 or a single ROADM can be configured to access all of the fiber pairs of the cable.

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

[0083] The architecture described herein can be used for all bidirectional fiber pairs of bidirectional communication traffic. In alternative embodiments, it can also be used based on single fibers and other applications such as unidirectional data acquisition from undersea scientific applications or sensors.

[0084] Certain examples of the present disclosure have been described above. It is, however, expressly intended that the present disclosure is not limited to these examples, but rather the addition and modification of what has been expressly described herein are to be included in the scope of the disclosed examples. Moreover, it is to be understood that the features of the various examples described herein are not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not expressly described herein. Indeed, variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art upon reading the foregoing description. The disclosed examples are therefore to be construed in all aspects as non-limiting examples of the present disclosure.

[0085] It is emphasized that the Abstract of the present disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the preceding Detailed Description, various features are grouped together in a single example to simplify the disclosure. This disclosure approach should not be interpreted as reflecting an intention that the claimed examples require more features than expressly recited in each claim. On the contrary, as reflected in the following claims, the inventive subject matter lies in less than all the 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 respective terms "comprising" and "wherein," respectively. Moreover, the terms "first," "second," "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[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 forms disclosed. Many modifications and variations are possible in light of the present disclosure. It is intended that the scope of the present disclosure be limited not by this detailed description, but by the appended claims. Future applications claiming priority to the present application may claim the disclosed subject matter in various ways and may generally include any set of one or more limitations variously disclosed or otherwise presented herein.

Claims

1. A submarine optical fiber cable routing system, comprising: A branching unit coupled to three optical fiber cables, each optical fiber cable having a plurality of optical fiber pairs, the branching unit comprising: a plurality of switches for each optical fiber pair, the plurality of switches being configurable to enable an optical fiber pair from any one of the three optical fiber cables to be switched to allow routing to any one of the other two of the three optical fiber cables; and a controller operable to receive a remote command signal and configure the plurality of converters as directed by the received remote command signal, wherein each optical fiber pair comprises an inbound optical fiber and an outbound optical fiber, wherein the inbound optical fiber receives optical information from the branching unit and the outbound optical fiber delivers different optical information to the branching unit; and The controller is further operable to generate a switching triangle, wherein a first switch of the plurality of switches for each fiber pair comprises: an input coupled to the outbound optical fiber; a first output selectively coupled to the input for providing different optical information to an optical fiber pair in another one of the three optical fiber cables; and A second output, selectively coupled to the input, is configured to provide different optical information to an optical fiber pair in another one of the three optical fiber cables.

2. The submarine fiber optic cable routing system of claim 1 , wherein the plurality of converters for each fiber pair of a first fiber optic cable of the three fiber optic cables comprises a first converter coupled to a first fiber of the fiber pair and a second converter coupled to a second fiber of the fiber pair.

3. The submarine optical fiber cable routing system of claim 2, wherein the first converter comprises: a first connector optically coupled to a first optical fiber of the optical fiber pair; a second connector optically coupled to a converter coupled to a second fiber optic cable of the three fiber optic cables; as well as A third connector is optically coupled to another converter coupled to a third fiber optic cable of the three fiber optic cables.

4. The submarine optical fiber cable routing system according to claim 2, wherein: a first converter configured to connect a first optical fiber of the first fiber optic cable to a first optical fiber of a fiber pair in a second fiber optic cable of the three fiber optic cables; as well as The second converter is configured to connect the second optical fiber of the first fiber optic cable to the second optical fiber of the optical fiber pair in the second of the three fiber optic cables.

5. The submarine optical fiber cable routing system of claim 1 , wherein the controller is operable to: monitoring each of a plurality of fiber pairs in each of the three fiber optic cables coupled to the branching unit, and The remote command signal is received, wherein the remote command signal is transmitted through an optical fiber pair selected from the plurality of optical fiber pairs to be converted, wherein the remote command signal for configuring the plurality of converters is transmitted on a monitor channel of a wavelength division multiplexing signal transmitted on the selected optical fiber pair.

6. The submarine fiber optic cable routing system of claim 1, wherein the routing is limited by the fiber pair count of the fiber optic cables in the three fiber optic cables.

7. The submarine optical fiber cable routing system according to claim 1, further comprising: A reconfigurable optical add / drop multiplexer is coupled to one or more optical fiber pairs.

8. A submarine optical fiber cable routing system comprising: a first submarine optical fiber cable, a second submarine optical fiber cable, and a third submarine optical fiber cable, wherein each of the first submarine optical fiber cable, the second submarine optical fiber cable, and the third submarine optical fiber cable comprises a plurality of optical fiber pairs; as well as a branching unit 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, wherein the branching unit comprises: a first set of distributable converters configured to optically couple to a plurality of optical fiber pairs in the first submarine optical fiber cable, wherein each distributable converter in the first set is coupled to a respective optical fiber pair in the first submarine optical fiber cable; a second set of assignable converters configured to optically couple to a plurality of optical fiber pairs in the second submarine optical fiber cable, wherein each assignable converter in the second set is coupled to a respective optical fiber pair in the second submarine optical fiber cable; a third set of allocable converters configured to optically couple to a plurality of optical fiber pairs in the third submarine optical fiber cable, wherein each allocable converter in the third set is coupled to a respective optical fiber pair in the third submarine optical fiber cable; a plurality of optical pathways coupling the respective allocable converters in each of the first, second, and third groups of allocable converters to one another; and a controller coupled to each respective allocable converter in each of the first, second, and third groups of allocable converters, wherein the controller is operable to: assigning a respective first group of allocable converters from said first group to a respective second group of allocable converters and to a respective third group of allocable converters, wherein each of the plurality of optical fiber pairs in the first submarine optical fiber cable comprises an outbound optical fiber for outputting an optical signal from a first site, and an inbound optical fiber for delivering the optical signal to the first site; Each of the plurality of optical fiber pairs in the second submarine optical fiber cable comprises an outbound optical fiber for outputting an optical signal from a second site, and an inbound optical fiber for delivering the optical signal to the second site; and Each of the plurality of optical fiber pairs in the third submarine optical fiber cable comprises an outbound optical fiber for outputting an optical signal from a third site, and an inbound optical fiber for delivering the optical signal to the third site, wherein the controller is further operable to generate a conversion triangle, each of a first allocable converter in the first set of allocable converters, a first allocable converter in the second set of allocable converters, and a first allocable converter in the third set of allocable converters comprising: an input coupled to the outbound optical fiber; a first output selectively coupled to the input for providing different optical information to an optical fiber pair in another one of the three optical fiber cables; and A second output, selectively coupled to the input, is configured to provide different optical information to an optical fiber pair in another one of the three optical fiber cables.

9. The optical cable routing system of claim 8, wherein each of the first group of allocable converters, the second group of allocable converters, and the third group of allocable converters is subdivided into a plurality of allocable converter groups, and Each of the plurality of groups of allocable converters in the first set of allocable converters has a corresponding group in each of the second set of allocable converters and the third set of allocable converters.

10. The optical cable routing system of claim 8, wherein: a number of allocable converters in the group of allocable converters based on a minimum number of optical fiber pairs in a respective one of the first submarine optical fiber cable, the second submarine optical fiber cable, or the third submarine optical fiber cable, and Each corresponding group of allocable converters has the same number of allocable converters.

11. The fiber optic cable routing system of claim 8, wherein the controller is further operable to: subdividing the first set of allocable converters into groups of the first set of allocable converters; subdividing the second set of allocable converters into groups of second sets of allocable converters; subdividing the third set of allocable converters into groups of third sets of allocable converters; and Respective groups from the first set of allocable converters are assigned to corresponding groups from the second and third sets of allocable converters.

12. The optical cable routing system of claim 11, further comprising: a plurality of reconfigurable optical add / drop multiplexers coupled to selected optical fiber pairs in each of the first, second, and third submarine optical fiber cables, wherein each respective reconfigurable optical add / drop multiplexer in the plurality of reconfigurable optical add / drop multiplexers is coupled to a respective selected optical fiber pair before coupling the respective selected optical fiber pair to a respective distributable converter.

13. The optical cable routing system of claim 12, wherein the controller further comprises: a control connection to each respective reconfigurable optical add / drop multiplexer of the plurality of reconfigurable optical add / drop multiplexers; and The controller is further operable to: receiving a remote command signal transmitted on a monitoring channel of a wavelength division multiplexed signal transmitted on the corresponding selected optical fiber pair in each of the first, second, and third submarine optical fiber cables; as well as The operation of each respective reconfigurable optical add / drop multiplexer in the plurality of reconfigurable optical add / drop multiplexers is controlled based on the remote command signal.

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