A process and disc fiber method for using multi-core fusion in a submarine cable jointing box

Abstract

The application relates to a process and a fiber coiling method using multi-core fusion in a submarine cable splice closure, which comprises the following steps: S1, in a submarine cable splice closure splicing site, grouping optical fibers disassembled from submarine cables according to the one-time fusion capacity of a multi-core fusion machine to obtain multiple groups of optical fibers, and cutting each group of optical fibers according to a predetermined cutting length; S2, sequentially performing fiber arranging and glue coating on each group of optical fibers to bond each group of optical fibers into a temporary optical fiber ribbon; S3, one-time fusing the temporary optical fiber ribbons by using the multi-core fusion machine, and installing a multi-core optical fiber heat shrink tube at the fusing position; and S4, coiling each group of optical fibers, which have completed fusing and multi-core optical fiber heat shrink tube installation, into a coiling area of a fiber coiling tray, and fixing the multi-core optical fiber heat shrink tube on a heat shrink sleeve installation base outside the coiling area. The application has the advantages of adapting non-ribbon optical fibers to the input form of the multi-core fusion machine on site and significantly shortening the process time of the fiber coiling in the splice closure.

Description

Technical Field

[0001] This application relates to the field of submarine optical cable splicing technology, and in particular to a process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box. Background Technology

[0002] With the continuous improvement of communication capacity in submarine optical cables, the number of optical fiber cores contained in submarine optical cables has increased from a few cores in the early days to dozens of cores, and now to dozens to hundreds of cores. After the submarine optical cable is manufactured in the factory, it needs to be spliced ​​through a submarine optical cable splice box during the submarine laying process. The fiber coiling process in the submarine optical cable splice box is the core link in splicing quality and construction efficiency. The fiber coiling process requires the spliced ​​optical fiber to be coiled in an orderly manner into the coiling area of ​​the fiber coiling tray according to a certain path, and each splice point is mechanically protected and fixed in position to prevent additional optical loss or fiber breakage in the long-term working environment.

[0003] The optical fibers disassembled from the interior of a submarine optical cable are loosely distributed without a ribbon-like pattern, circling the central protective tube along the cable's cross-section. Early fiber coiling processes used a single-core fiber fusion splicer to splice each fiber individually, then installed and positioned the heat-shrink tubing on each fiber individually, and finally coiled each fiber into a coiling tray. This process was acceptable when the number of cores was small, but as the number of cores in a submarine optical cable increased to tens or even hundreds, the time required for splicing each core individually and positioning each heat-shrink tubing increased linearly with the number of cores. The total time for a single splice point often reached 6 to 8 hours, becoming a bottleneck restricting the laying schedule of submarine optical cables.

[0004] To improve splicing efficiency, the industry has developed multi-core fiber optic fusion splicers, capable of splicing up to 12 fibers in a single operation. A heat-shrink tubing is installed at the splice location to uniformly protect the fusion point. However, multi-core fiber optic fusion splicers require the fibers input into the V-groove of the splicer to be in a ribbon-like shape; that is, a group of fibers needs to be aligned side-by-side with a fixed spacing to form a fiber ribbon. This shape requirement fundamentally contradicts the non-ribbon, loose distribution of fibers when submarine optical cables leave the factory—the stronger the splicing capability of the multi-core fusion splicer, the higher the requirement for the neatness of the fiber input shape. However, the splicing work at submarine optical cable splice boxes must be completed on-site, and the prefabrication process of ribbon-like optical cables in the factory cannot meet this shape requirement. If the morphology adaptation is skipped and the fiber is forcibly inserted into the fusion splicer, the probability of the fiber jumping or misaligning in the V-groove will increase rapidly, causing fusion failure, misaligned fibers, or even fiber breakage. If a ribbon structure is prefabricated outside the splice box and then returned to the splice box, the process time advantage of multi-core fusion splicing over single-core fusion splicing is lost, and the prefabricated rigid structure cannot adapt to the winding requirements of the limited space inside the splice box.

[0005] Among existing technologies concerning fiber coiling processes within submarine optical cable splice boxes, the fiber coiling method disclosed in publication number CN105301697A, while having established a complete coiling path and various structural component matching rules, still relies on single-core fusion splicing as its starting point. It does not address the fiber morphology adaptation required for multi-core fusion splicing, and its grouping logic based on optical devices cannot be directly applied to multi-core fusion splicing scenarios grouped by the fusion splicing capacity of multi-core fusion splicers. Therefore, there has been a long-standing desire in the field to propose a method that can adapt the disassembled non-ribbon optical fibers to the input morphology requirements of multi-core fusion splicers at the splicing site of submarine optical cable splice boxes, and integrate the efficient fusion of multi-core fusion with the orderly coiling within the fiber coiling tray into a complete process chain. Summary of the Invention

[0006] In order to adapt the non-ribbon optical fibers disassembled from the submarine optical cable to the input configuration requirements of the multi-core fusion splicer at the submarine optical cable splice box splicing site, and to integrate the efficient fusion of multi-core splicing with the orderly winding in the fiber tray into a complete process chain, this application provides a process, fiber winding method and related apparatus for using multi-core fusion splicing in a submarine optical cable splice box.

[0007] Firstly, this application provides a process and fiber coiling method for multi-core fusion splicing in a submarine optical cable splice box, which adopts the following technical solution: A process and fiber coiling method for multi-core fusion splicing in submarine optical cable splice boxes includes the following steps: S1. At the splicing site of the submarine optical cable splice box, the optical fibers disassembled from the submarine optical cable are grouped according to the one-time splicing capacity of the multi-core fusion splicer to obtain multiple groups of optical fibers, and each group of optical fibers is cut according to the predetermined cutting length.

[0008] S2. Perform fiber optic alignment and adhesive application on each group of optical fibers in sequence to bond each group of optical fibers into a temporary optical fiber ribbon. Fiber optic alignment involves using a fiber optic aligner to arrange each group of optical fibers side by side according to a predetermined arrangement rule. Adhesive application involves applying optical fiber adhesive to the arrangement section of each group of optical fibers.

[0009] S3. Use a multi-core fusion splicer to splice each set of temporary optical fiber ribbons after fiber arrangement and gluing in one go, and install multi-core optical fiber heat shrink tubing at the splice position.

[0010] S4. Coil each group of optical fibers that have been spliced ​​and multi-core fiber heat shrink tubing installed into the coiling area of ​​the fiber coiling tray, and fix the multi-core fiber heat shrink tubing on each group of optical fibers to the heat shrink tubing mounting base outside the coiling area.

[0011] By adopting the above technical solution, the ribbon input shape required by the multi-core fusion splicer is directly formed at the splicing site of the submarine optical cable splice box through the coordinated action of the fiber optic cable arranger and fiber adhesive. This moves the multi-core fusion splicing process, which could originally only be completed in the factory ribbon optical cable manufacturing process, to the splice box site. The grouping rules are bound to the one-time fusion splicing capacity of the multi-core fusion splicer, so that each group of optical fibers, each multi-core optical fiber heat shrink tube, and the fixed position on the fastening tape form a stable information chain with a one-to-one correspondence. The entire process chain, from grouping to ribbonization, to fusion splicing, to heat shrink tube protection, to coiling, is consistent in form and the misaligned fiber path is cut off. The temporary optical fiber ribbon formed on site stabilizes the optical fiber position during the fusion splicing and heat shrink tube installation stages, and relies on geometric positioning to avoid entering the coiling bending area during the coiling stage. This makes the entire process chain have both the high efficiency of multi-core fusion splicing and adaptable to the bending requirements of the limited space in the fiber coiling tray.

[0012] Optionally, the adhesive application in S2 includes a first-stage adhesive application and a second-stage adhesive application. The first-stage adhesive application involves applying fiber adhesive to each group of fibers after they have been assembled within the fiber assembler. The length of the first-stage adhesive application on each group of fibers ensures that each group maintains a ribbon-like shape after being removed from the fiber assembler. The second-stage adhesive application is performed after each group of fibers has been removed from the fiber assembler. The length of the second-stage adhesive application is greater than the length of the first-stage adhesive application and corresponds to the number of times each group of fibers can be repeatedly spliced.

[0013] By adopting the above technical solution, the first adhesive coating section undertakes the function of assisting in the removal, while the second adhesive coating section undertakes the function of remelting the remaining amount. The two adhesive coating sections are clearly separated in terms of position, function, and length, so that the two conflicting process requirements of preventing the fiber ejector from scattering during removal and minimizing the cutting loss during remelting can be met simultaneously through spatial separation.

[0014] Optionally, the length of the second adhesive application and the predetermined cutting length in S1 are synchronously set according to the number of repeatable fiber splicing operations. Each increase in the number of repeatable fiber splicing operations constitutes a step in the synchronous setting relationship. The length of the second adhesive application is calculated based on the number of repeatable fiber splicing operations. For each step increase in the number of repeatable fiber splicing operations, the increase in the length of the second adhesive application is not less than the fiber cut length after a single splicing operation. The predetermined cutting length is calculated based on the coiling allowance corresponding to the number of repeatable fiber splicing operations. For each step increase in the number of repeatable fiber splicing operations, the predetermined cutting length increases synchronously, increasing the coiling allowance in the coiling area of ​​the fiber coiling tray to accommodate the extended fiber.

[0015] By adopting the above technical solution, the second-stage adhesive coating length and the predetermined cutting length are linked to the gear, avoiding process mismatches such as sufficient adhesive coating section but insufficient fiber coiling allowance or sufficient fiber coiling allowance but insufficient adhesive coating section, and enabling process expansion to be upgraded in place within the gear without redesigning the tooling.

[0016] Optionally, the first and second adhesive coatings are located within a straight section outside the coiling area of ​​the fiber tray on each group of optical fibers. The portion of each group of optical fibers coiled into the coiling area in S4 is the uncoated fiber segment within that group. The straight section containing the first and second adhesive coatings does not physically overlap with the coiled segment coiled into the coiling area in S4.

[0017] By adopting the above technical solution, the rigidity requirement of the adhesive coating section and the flexibility requirement of the coiling section are simultaneously met through geometric separation, so that the adhesive layer stabilizes the fiber position during the fusion splicing and heat shrink tubing installation stages, while the coiling section retains the independent mobility of the uncoated fiber to adapt to the bending radius within the fiber coil tray.

[0018] Optionally, the predetermined arrangement rules in S2 ensure that the order of each optical fiber in the fiber assemblies corresponds one-to-one with the order of each group of optical fibers specified in the system fusion splice pattern, and the geometric arrangement of the temporary fiber ribbons after adhesive application corresponds one-to-one with the order of each group of optical fibers in the system fusion splice pattern. In S3, the splicing sequence of the multi-core fusion splicer is consistent with the sequence of the fiber assemblies. Between S3 and S4, the following step is also included: verifying the correct splicing sequence of each group of optical fibers by checking the order of the two optical fibers at both ends of each group of temporary fiber ribbons.

[0019] By adopting the above technical solution, the fiber sequence information is materialized from the system fusion splice pattern into the geometric arrangement of the fiber ribbon in one go, which simplifies the color sequence verification after splicing from core-by-core verification to verifying the entire sequence by only checking the two fibers at both ends of the fiber ribbon, and significantly improves the error detection efficiency.

[0020] Optionally, in S4, the fiber optic cables are coiled within the coiling area of ​​the fiber optic tray according to the following directional arrangement rules: the fiber optic tray has a coiling surface that serves as the coiling area, and each group of fibers is coiled within the coiling area of ​​the coiling surface. The spliced ​​fiber optic cables are divided into a left fiber group and a right fiber group according to the two fiber ends of the submarine optical cable located on either side of the submarine optical cable splice box. The left fiber group is continuously coiled a predetermined number of times in the same coiling direction within the coiling area. The right fiber group's first turn within the coiling area is in the same coiling direction as the left fiber group, and from the second turn onwards, it switches to the opposite coiling direction. After the right fiber group's coiling direction is switched, the forward direction of the last half-turn of the right fiber group is aligned with the entry direction of the end fixing device on the fiber optic tray, and the last half-turn of the fiber is fixed to the fiber optic tray by the end fixing device.

[0021] By adopting the above technical solution, the direction switching of the two loops on the same side of the right fiber group makes the forward direction of the last half loop of fiber consistent with the inlet direction of the end fixing component, avoiding the introduction of additional optical loss due to the forced twisting of the fiber when fixing the last half loop of fiber by the end fixing component. The consistent direction of the first loop on both sides also facilitates the uniform transition of the fiber from the root end of the optical cable to the coiling area.

[0022] Optionally, the multi-core fiber optic heat shrink tubing in S4 is fixed to the heat shrink tubing mounting base in the following manner: After each group of fibers completes the coiling in S4, the multi-core fiber optic heat shrink tubing is attached and fixed to the heat shrink tubing mounting base using fasteners. The tightening direction of the fasteners is adaptively determined based on the total number of coils for the left and right fiber groups: in response to the total number of coils for the left and right fiber groups being an integer, the fasteners are tightened in the direction away from the coiling surface, so that the multi-core fiber optic heat shrink tubing is attached to the side of the heat shrink tubing mounting base closest to the coiling surface; in response to the total number of coils for the left and right fiber groups being an integer plus half a turn, the fasteners are tightened in the direction close to the coiling surface, so that the multi-core fiber optic heat shrink tubing is attached to the side of the heat shrink tubing mounting base opposite to the coiling surface.

[0023] By adopting the above technical solution, the fastener tightening direction is adaptively reversed according to the two types of termination states based on the total number of optical fiber coils, so that the attachment position of the multi-core optical fiber heat shrink tubing always avoids the entrance direction of the optical fiber entering the heat shrink tubing installation area, thus avoiding additional bending loss caused by compressing the optical fiber entrance.

[0024] Optionally, single-sided or double-sided fiber coiling can be selected based on the comparison between the total number of fiber cores in the submarine optical cable and the single-sided capacity threshold: If the total number of fiber cores in the submarine optical cable does not exceed the single-sided capacity threshold, S1 to S4 are performed on the front side of the fiber coiling tray; if the total number of fiber cores in the submarine optical cable exceeds the single-sided capacity threshold, each group of fibers is divided into a front fiber group and a back fiber group. The total number of cores in the front fiber group does not exceed the single-sided capacity threshold. The grouping in S1 covers all fibers common to both the front and back fiber groups. S1 to S4 are performed on the front side of the fiber coiling tray for the front fiber group, and S2 to S4 are performed on the back side of the fiber coiling tray for the back fiber group. The coiling direction arrangement in S4 of the back fiber group is the same as that in S4 of the front fiber group.

[0025] By adopting the above technical solution, the fiber capacity of the fiber tray can be doubled when the number of cores exceeds the single-sided capacity threshold by enabling back-side winding. Furthermore, the same winding direction arrangement rules are used on both sides to maintain process consistency, so that the expansion from single-sided to double-sided process does not increase the cognitive burden on the operator.

[0026] Optionally, if the total number of fiber cores in the submarine optical cable exceeds the single-sided capacity threshold, the processes for the front fiber assembly and the back fiber assembly are performed in a staggered sequence as follows: complete all processes S1 to S4 for the front fiber assembly; after completing all processes for the front fiber assembly, flip the fiber tray over so that the back of the fiber tray faces upwards as the new operating surface; perform all processes S2 to S4 for the back fiber assembly on the back of the fiber tray. The structural components on the fiber tray are divided into shared structural components for both front and back sides and independent structural components. The shared structural components for both front and back sides are installed in the predetermined positions during the front fiber assembly process. The independent structural components for the front fiber assembly are installed on the front of the fiber tray during the front fiber assembly process, and the independent structural components for the back fiber assembly are installed on the back of the fiber tray during the back fiber assembly process.

[0027] By adopting the above technical solution, the serial execution of the front and back processes allows the operator to focus on only one side at each stage, avoiding the conflict between fiber optic crossing and structural screws when the front and back are operated in parallel. The pre-installation of the shared structural components on the front and back and the separate reinstallation of the independent structural components on the front and back also eliminate the need for repeated disassembly and assembly of the shared structural components.

[0028] Optionally, if the fusion splicing of a certain group of optical fibers fails after reaching the number of repeatable splicing cycles in S3, the following three-level process degradation response is initiated for that group of optical fibers: Level 1 response: Strip the second section of adhesive from the group of optical fibers, and re-apply the second section of adhesive to the group of optical fibers. The length of the second section of adhesive and the predetermined cutting length are adopted according to the next level corresponding to the synchronous setting relationship, thereby increasing the number of repeatable splicing cycles. Level 2 response: If the fusion splicing of the group of optical fibers still fails after the Level 1 response, remove the group of optical fibers from the fiber assemblies, retain the grouping in S1 and the predetermined cutting length already used in the Level 1 response, and re-execute S2 and S3 for the group of optical fibers. Level 3 response: If the fusion splicing of the group of optical fibers still fails after the Level 2 response, mark the group of optical fibers as a faulty group and temporarily store it outside the fiber tray. After all S1 to S4 for the remaining groups are completed, re-execute S2 to S4 for the faulty group using a spare fiber segment.

[0029] By adopting the above technical solutions, the three-level response, which already covers the vast majority of fiber splicing failures with repeatable fiber splicing times, further covers splicing failure scenarios under extreme working conditions, reducing the impact of failures on the project schedule from scrapping the entire group to delaying a single group, and increasing the overall process success rate to nearly 100%.

[0030] Optionally, in S1, a second predetermined cutting length can be selected as the entry level, so that each group of optical fibers has the second level of repeatable fiber splicing capacity upon entry. When the second level of repeatable fiber splicing capacity is exhausted and the three-level process degradation response is initiated, the first-level response cuts the group of optical fibers from the second predetermined cutting length to the first predetermined cutting length, and continues to utilize the first level of repeatable fiber splicing capacity.

[0031] By adopting the above technical solution, the second level is used upon entry to make full use of the maximum number of repeatable fiber melting times. When downgrading, the fiber is cut to the first level to continue to utilize the remaining fiber melting opportunities, so that the first level and the second level form a bidirectional process path that covers the two typical operating practices of default entry and fault downgrading.

[0032] Optionally, the number of cores in each group of optical fibers shall not exceed twelve. Each group of optical fibers shall be arranged by a fiber optic assembly device and bonded into a temporary optical fiber ribbon with optical fiber adhesive, and then protected uniformly at the fusion splice position by a multi-core optical fiber heat shrink tubing.

[0033] By adopting the above technical solution, the grouping rule of twelve cores per group matches the ability of commercial multi-core fiber fusion splicers to splice four to twelve cores at a time, so that each multi-core fiber heat shrink tube covers the melting point of a group of fibers, and the number of groups is equal to the number of multi-core fiber heat shrink tubes.

[0034] Optionally, the first adhesive application on each fiber optic group is 20 mm long, and the second adhesive application on each fiber optic group is 100 to 150 mm long. After both the first and second adhesive applications are completed, allow one minute for the fiber adhesive to dry and bond.

[0035] By adopting the above technical solution, the first stage of adhesive application completes the removal assistance with minimal adhesive amount, the second stage of adhesive application provides sufficient remelting margin length, and the drying time of the two stages is one minute, which allows the optical fiber adhesive to reach a bonding strength sufficient to withstand subsequent process operations.

[0036] Optionally, the predetermined cutting length can be configured in two levels: the first level is the basic operating condition, with a predetermined cutting length of 845 mm and a second adhesive coating length of 100 mm, with each group of optical fibers coiled four full turns within the coiling area; the second level is the maximum operating condition, with a predetermined cutting length of 995 mm and a second adhesive coating length of 150 mm, with each group of optical fibers coiled four full turns plus a half turn within the coiling area. The predetermined cutting length of 995 mm in the second level is the maximum coiling length that can be accommodated in the fiber coiling tray.

[0037] By adopting the above technical solution, the two specific configurations cover typical working conditions and maximum remelting allowance working conditions. The first configuration corresponds to the working condition where the fastener is tightened in an integer number of turns away from the winding surface, and the second configuration corresponds to the working condition where the fastener is tightened in an integer number of turns plus half a turn towards the winding surface. The two configurations correspond to the two tightening directions of the fastener.

[0038] Optionally, the first predetermined cutting length corresponds to the minimum fiber length required for internal fiber retraction compensation in deep-water high-pressure working environment of the submarine optical cable, and the second predetermined cutting length corresponds to the upper limit of the maximum coiling length that can be accommodated in the fiber coil tray. The intermediate length between the first and second grades is not used in engineering practice.

[0039] By adopting the above technical solution, the lower limit of the predetermined cutting length is determined by the deep-water shrinkage compensation requirement of the submarine optical cable, and the upper limit is determined by the space constraint within the fiber tray. The two configurations cover the endpoints of the physically feasible predetermined cutting length range, simplifying the selection of process parameters from a continuous range to two discrete selections.

[0040] Optionally, the single-sided capacity threshold is 48 cores, and the front or back of the fiber tray can each hold a total of 48 fiber cores, corresponding to four groups.

[0041] By adopting the above technical solution, the single-sided capacity threshold of 48 cores corresponds to the upper limit of the single-sided capacity of four groups of 12-core fiber optic trays, enabling submarine optical cables in the range of 24 to 96 cores to complete the fiber optic splicing process in the splice box through single-sided or double-sided fiber optic splicing.

[0042] Optionally, the fasteners include heat shrink tubing fastening tape, double-sided tape, and locking strip. After the heat shrink tubing fastening tape is adhered to the double-sided tape, the multi-core fiber optic heat shrink tubing is centered and attached to the double-sided tape. After the heat shrink tubing fastening tape is tightened into place, it is fixed with a torque of 0.6 Nm by the locking strip, and the excess part of the heat shrink tubing fastening tape is cut off.

[0043] By adopting the above technical solution, the combination of heat shrink tubing fastening tape and double-sided adhesive achieves batch positioning of multi-core fiber optic heat shrink tubing, and the locking strip is fixed with a predetermined torque to keep the fastening tape taut in a long-term working environment.

[0044] Optionally, when the heat shrink tubing fastening tape is applied in a single layer, the predetermined number of multi-core fiber optic heat shrink tubes that can be accommodated is the integer part of the ratio of the width of the heat shrink tubing fastening tape to the diameter of the multi-core fiber optic heat shrink tube, and the predetermined number is four.

[0045] By adopting the above technical solution, the central layout rule of the heat shrink tubing fastening band accommodating four multi-core fiber heat shrink tubes maximizes the effective width of the fastening band. The multi-core fiber heat shrink tubes on the single-sided heat shrink tubing mounting base are arranged in a single layer and the number does not exceed four. The excess part is distributed by using the other side of the fiber coiling tray to perform a double-sided fiber coiling process.

[0046] Optionally, the end fixing component is a P-type clip, and four guide pins are provided in the winding area of ​​the fiber tray as support components for the fiber winding path. After each turn of winding, a fiber separator is installed on each of the guide pins at both ends of the fiber tray. After winding is completed, O-rings are installed on the four guide pins.

[0047] By adopting the above technical solution, the guide pin and the fiber separator work together to limit the winding path of the optical fiber and isolate adjacent coils. The O-ring applies axial limit to the optical fiber after winding, and the P-clamp fixes the end of the last half-turn of the optical fiber. Multiple structural components work together to form a complete winding path constraint system.

[0048] Optionally, a masking tape label is affixed to each fiber optic cable 150 mm from the end of the cable as a temporary group identification. The masking tape label is affixed outside the first and second adhesive coating sections. The masking tape label is removed after the color sequence check is completed in S3 and no incorrect fibers are confirmed, and before fiber coiling begins in S4.

[0049] By adopting the above technical solution, the attachment position of the masking tape is geometrically separated from the adhesive coating section, avoiding the label adhesive from contaminating the adhesive coating section and affecting the bonding quality of the optical fiber adhesive. The masking tape serves as a temporary group identification support for the color sequence verification process. It is removed in S4 before the fiber coiling begins after the color sequence verification is completed and there are no incorrect fibers. This avoids the label binding the natural bending of the optical fiber in the coiling area, which would cause additional loss. It also allows the operator to adjust the position of a single optical fiber in S4 according to the natural bending state of the optical fiber.

[0050] Optionally, the specific implementation of the predetermined arrangement rule is to arrange the fiber optic cables sequentially from one end to the other according to the color sequence specified in the system fusion splice pattern, so that the i-th slot in the fiber optic cable corresponds to the i-th color fiber of each group of optical fibers specified in the system fusion splice pattern.

[0051] By adopting the above technical solution, the color sequence, as the core information carrier of the system's fiber splicing pattern, is directly materialized into the physical position of the fiber optic cable, transforming the fiber order information from the design document into a visible physical arrangement.

[0052] Optionally, the fiber cut-off length after a single fusion is 30 mm. Under the second maximum operating condition, each group of fibers can be fused four times, and under the first basic operating condition, each group of fibers can be fused three times.

[0053] By adopting the above technical solution, a single cutting length of 30 mm and a second adhesive coating length of 100 mm to 150 mm are correlated with three to four remelting times, and the process allowance and fault coverage are specifically quantified.

[0054] Optionally, the shared structural components on both sides include a bend limiting block and a heat shrink tubing mounting base. The bend limiting block is fixed to the center of the fiber tray with a torque of one Newton-meter by an M3×12 screw to the heat shrink tubing mounting base. The independent structural components on both sides include a heat shrink tubing fastening band, a locking strip, an O-ring, and a P-clamp.

[0055] By adopting the above technical solution, the pre-installation of the shared structural components on both sides allows the bending limit block of the fiber optic tray to be installed only once in the double-sided process. The independent structural components on both sides are installed separately from the corresponding sides of the fiber optic tray without any screw insertion conflict.

[0056] Optionally, the spare fiber segment can be a reserved spare fiber segment in the submarine optical cable or a specially configured spare fusion fiber, and the color sequence of the spare fiber segment can be consistent with the color sequence of the fault group.

[0057] By adopting the above technical solution, the fault group can restore the integrity of the overall optical fiber system through the backup optical fiber segment. The color sequence of the backup optical fiber segment remains consistent, which allows the fault group to maintain its role in the system's fiber splicing pattern.

[0058] Optionally, after winding, the O-rings installed on the four guide pins are positioned three to four millimeters from the top of the guide pins.

[0059] By adopting the above technical solution, the installation position of the O-ring three to four millimeters from the top of the guide pin allows the last half-circle of optical fiber to cross over from the top of the guide pin and enter the P-clamp, and the O-ring does not obstruct the P-clamp fixing process.

[0060] Secondly, the submarine optical cable splice box provided in this application adopts the following technical solution: A submarine optical cable splice box, wherein the fiber coiling process inside the submarine optical cable splice box performs the above-mentioned process and fiber coiling method of using multi-core fusion splicing in the submarine optical cable splice box.

[0061] In summary, this application includes at least one of the following beneficial technical effects: 1. This application uses fiber optic cable trays and fiber adhesive to form temporary fiber ribbons at the splicing site of the submarine optical cable splice box, directly forming the ribbon input shape required by the multi-core fusion splicer at the splice box site. This shortens the splicing process, which originally took six to eight hours to splice each single core individually, to no more than two hours, saving more than four hours of splicing time.

[0062] 2. This application achieves a differentiated division of labor in two-stage adhesive application and links the second stage adhesive application length with the predetermined cutting length, so that the adhesive application stage can simultaneously meet conflicting process requirements in terms of auxiliary removal, remelting allowance, and geometric isolation. It also establishes a quantifiable parameter correspondence between the process allowance and the number of remelting cycles, covering the redundancy of three to four remelting processes.

[0063] 3. This application achieves orderly winding of submarine optical cables in the range of 24 to 96 cores within a universal fiber tray through the coordinated use of multiple rules such as winding direction arrangement, fastener tension direction self-adaptation, double-sided threshold switching and timing staggering, and three-level process degradation response. The process success rate of a single splice point is close to 100%. Attached Figure Description

[0064] Figure 1 This is a schematic diagram showing the overall structure of the submarine optical cable splice box and the positional relationship of the fiber optic tray provided in the embodiments of this application; Figure 2 This is a flowchart of a process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box, provided in an embodiment of this application; Figure 3 This is a schematic diagram of the first and second adhesive application processes provided in the embodiments of this application; Figure 4 This is a schematic diagram showing the correspondence between the fiber optic header sequence, the fusion splicing sequence of the multi-core fusion splicer, and the geometric arrangement of the temporary fiber optic ribbon provided in the embodiments of this application; Figure 5 This is a schematic diagram of the fiber coiling path inside the fiber coiling tray provided in the embodiments of this application; Figure 6 This is a schematic diagram of the fastener tensioning direction working condition adaptation provided in the embodiments of this application.

[0065] 100. Submarine optical cable splice box; 110. Fiber optic tray; 111. Coiling area; 112. Coiling surface; 120. Submarine optical cable; 121. Left optical cable end; 122. Right optical cable end; 130. Guide pin; 131. Fiber optic separator; 140. P-type clip; 150. Heat shrink tubing mounting base; 160. Fastener; 200. Fiber optic cable tray; 201. Fiber optic cable tray slot; 210. Multi-core fusion splicer; 300. Temporary fiber optic ribbon; 301. First adhesive-coated section; 302. Second adhesive-coated section; 310. Multi-core fiber optic heat shrink tubing; 320. Masking tape label; 410. Left fiber optic group; 420. Right fiber optic group. Detailed Implementation

[0066] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. The embodiments described in this application are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0067] This application discloses a process and fiber coiling method for multi-core fusion splicing in submarine optical cable splice boxes. (Refer to...) Figure 1 and Figure 2 The optical fibers disassembled from the submarine optical cable 120 are loosely distributed without a ribbon shape, arranged around the central protective tube of the optical cable along the cross-section of the cable. The submarine optical cable 120 enters the submarine optical cable splice box 100 from two optical cable ends located on both sides of the splice box 100. The optical cable end on the left is called the left optical cable end 121, and the optical cable end on the right is called the right optical cable end 122. The submarine optical cable splice box 100 is provided with a fiber coiling tray 110. One or both sides of the fiber coiling tray 110 are provided with a coiling area 111 for coiling optical fibers. The surface of the fiber coiling tray 110 where the coiling area 111 is located is defined as the coiling surface 112. A heat shrink tubing mounting base 150 is provided outside the coiling area 111 of the fiber coiling tray 110 for fixing the multi-core optical fiber heat shrink tubing 310. The method of this application includes steps S1 to S4, and each step is described in detail below through embodiments.

[0068] Example 1: Complete process of single-sided fiber coiling under basic working conditions Example 1 describes the complete process of single-sided fiber coiling on a fiber tray 110 under the basic condition that the total number of fiber cores in the submarine optical cable 120 does not exceed the single-sided capacity threshold, i.e., the total number of fiber cores is less than or equal to 48 cores. Under the basic condition, the first predetermined cutting length is used, i.e., the predetermined cutting length is 845 mm.

[0069] S1: Grouping, Segmentation, and Group Identification Reference Figure 2 At the splicing site of the submarine optical cable splice box 100, the optical fibers disassembled from the submarine optical cable 120 are grouped according to the one-time splicing capacity of the multi-core fusion splicer 210 to obtain multiple groups of optical fibers. The one-time splicing capacity of the multi-core fusion splicer 210 is the upper limit of the number of optical fiber cores spliced ​​in one operation. In this embodiment, the one-time splicing capacity of the multi-core fusion splicer 210 is 12 cores. For example, for a 48-core submarine optical cable 120, it is divided into 4 groups of optical fibers with 12 cores each. The number of cores in each group of optical fibers does not exceed the upper limit of the one-time splicing capacity of the multi-core fusion splicer 210.

[0070] After grouping, a masking tape label 320 is affixed to the fiber optic cable at a distance of 150 mm from the end of each fiber as a temporary group identification. The masking tape label 320 is placed outside the subsequent adhesive coating section to avoid label adhesive contaminating the adhesive coating section and affecting the bonding quality of the fiber optic adhesive. The masking tape label 320 serves as a temporary group identification to support group identification and color sequence verification in the S2 fiber optic adhesive coating, S3 fusion splicing heat shrink tubing installation, and the color sequence verification process at the end of S3, and also supports the process degradation response that is initiated when the color sequence verification fails. After the color sequence verification is completed and no incorrect fibers are confirmed, and before the S4 fiber coiling begins, the masking tape label 320 is removed. This allows the fiber optic cable to bend in an arc within the S4 coiling area 111 without being restrained by the label, avoiding additional loss caused by the label adhesive layer on the bent section of the fiber, and allowing the operator to adjust the position of individual fibers in S4 according to the natural bending state of the fiber.

[0071] Subsequently, each group of optical fibers is cut to the predetermined cutting length. Under basic operating conditions, the predetermined cutting length is 845 mm. The fiber cutting is based on the inner side of the fiber tray 110, and the excess fiber is cut off after measuring the specified length with a tape measure.

[0072] S2: Fiber arrangement, adhesive coating, and formation of temporary fiber ribbon S2 includes sub-steps S21 to S23.

[0073] S21 First Stage Adhesive Application: Refer to Figure 3 and Figure 4Each group of optical fibers is placed into the fiber optic header 200 and arranged side-by-side in the header slots 201 according to a predetermined arrangement rule. The fiber optic header 200 has the same number of side-by-side header slots 201 as the multi-core fusion splicer 210's single-sponge capacity, with each header slot 201 corresponding to one optical fiber. In this embodiment, the fiber optic header 200 is a 12-slot header, such as the Fujikura RT-02 type. The predetermined arrangement rule is as follows: when each group of optical fibers enters the fiber optic header 200, they are arranged sequentially from one end of the header slot 201 to the other according to the color sequence specified in the system fusion splice chart, so that the i-th header slot 201 in the fiber optic header 200 corresponds to the i-th color fiber of that group of optical fibers specified in the system fusion splice chart. Through this arrangement, the position of each optical fiber in the fiber optic header 200 corresponds one-to-one with the order of that group of optical fibers specified in the system fusion splice chart.

[0074] After the fiber optic cable is laid out, fiber optic adhesive, such as Fujikura FAA-03A type, is applied to the fiber optic cable group inside the fiber optic cable header 200. The first adhesive-coated section 301 is applied to both the top and bottom surfaces of the fiber optic cable group, with a length of approximately 20 mm. The length of the first adhesive-coated section 301 ensures that the fiber optic cable group maintains a ribbon-like shape after being removed from the fiber optic cable header 200, preventing it from unraveling during removal. After the first adhesive-coated section 301 is applied, wait approximately 1 minute for the fiber optic adhesive to dry and bond.

[0075] S22 Removal: The group of optical fibers, after the first adhesive coating section 301 has been applied, bonded, and dried, is removed from the fiber optic assembly 200. Since the first adhesive coating section 301 has bonded the group of optical fibers into a ribbon shape, the optical fiber group retains its ribbon shape after being removed from the fiber optic assembly 200 and can be used as a temporary optical fiber ribbon 300 in subsequent processes.

[0076] S23 Second-stage adhesive application: Apply fiber adhesive to both the top and bottom surfaces of the removed fiber group to form the second-stage adhesive application section 302. The length of the second-stage adhesive application section 302 is greater than the length of the first-stage adhesive application section 301, and corresponds to the number of times the fiber group can be repeatedly spliced. Under basic operating conditions, the length of the second-stage adhesive application section 302 is 100 mm. After the second-stage adhesive application section 302 is completed, wait approximately 1 minute for the fiber adhesive to dry and bond.

[0077] The length of the second adhesive-coated section 302 and the predetermined cutting length in S1 are synchronously set according to the number of repeatable fiber fusions. Each increase in the number of repeatable fiber fusions constitutes a new level in the synchronous setting relationship. The length of the second adhesive-coated section 302 is calculated based on the required refusion allowance corresponding to the number of repeatable fiber fusions. The fiber cut length after a single fiber fusion is approximately 30 mm. The length of the second adhesive-coated section 302 is greater than the cumulative fiber cut length required for the number of repeatable fiber fusions in this level, ensuring that the second adhesive-coated section 302 can maintain its ribbon shape after being peeled and reworked within the number of repeatable fiber fusions in this level. The predetermined cutting length is calculated based on the coiling allowance corresponding to the number of repeatable fiber fusions. Each increase in the number of repeatable fiber fusions increases the predetermined cutting length by 150 mm, increasing the coiling area 111 of the fiber coiling tray 110 by half a turn of coiling allowance to accommodate the extended fiber. This application provides two specific configurations: The first configuration is the basic working condition, with a predetermined cutting length of 845 mm and a second adhesive-coated section 302 length of 100 mm, corresponding to 3 repeatable fiber melting cycles. In this configuration, the 100 mm section can withstand 3 × 30 mm = 90 mm of cumulative cutting while retaining a 10 mm margin. The second configuration is the maximum working condition, with a predetermined cutting length of 995 mm and a second adhesive-coated section 302 length of 150 mm, corresponding to 4 repeatable fiber melting cycles. In this configuration, the 150 mm section can withstand 4 × 30 mm = 120 mm of cumulative cutting while retaining a 30 mm margin. Compared to the first configuration, the second configuration increases the number of repeatable fiber melting cycles by one, and the predetermined cutting length increases by 150 mm, consistent with the aforementioned synchronous setting. The second-tier predetermined cutting length of 995 mm is the upper limit of the maximum coiling length that can be accommodated within the fiber optic tray 110. Increasing the cutting length further will result in insufficient space within the coiling area 111 of the fiber optic tray 110, and excessively long fiber lengths may cause multiple coils to not be neatly accommodated within the coiling area 111, leading to local fiber crossings or bends. The first-tier predetermined cutting length of 845 mm is the lower limit of the predetermined cutting length. In the deep-water, high-pressure working environment, the internal optical fibers of the submarine optical cable 120 are affected by factors such as compression from the outer sheath and reinforcing members, and temperature changes, causing them to retract into the cable. The predetermined cutting length needs to reserve sufficient length to compensate for the retraction, avoiding tensile stress near the splice point due to excessively short cutting length, which could cause additional optical loss or even fiber breakage. 845 mm is the minimum cutting length that meets the deep-water retraction compensation requirements in engineering practice; reducing the cutting length further will not guarantee the retraction margin. Therefore, the predetermined cutting length of this application is limited to between 845 mm and 995 mm, corresponding to two specific configurations. The intermediate length between the first and second grades, such as 920 mm, is of little significance in engineering practice as it neither increases the number of remelted fibers nor further enhances the deep-water shrinkage compensation capability. Therefore, the intermediate length is not used in actual processes.

[0078] The first adhesive-coated section 301 and the second adhesive-coated section 302 are both located within a straight section outside the coiling area 111 of the fiber tray 110 on this group of optical fibers. This straight section is the straight segment of this group of optical fibers from the end of the optical cable to the heat shrink tubing mounting base 150. The portion of each group of optical fibers coiled into the coiling area 111 in S4 is the uncoated fiber segment of each group of optical fibers. The straight section containing the first adhesive-coated section 301 and the second adhesive-coated section 302 does not overlap with the coiled segment coiled into the coiling area 111 in physical position, so that the adhesive-coated section stabilizes the fiber position during the splicing and heat shrink tubing installation stages, while the coiled segment retains the independent mobility of the uncoated fiber to adapt to the coiling bending radius.

[0079] After step S23, the optical fibers are bonded together with fiber adhesive to form a temporary fiber ribbon 300. The geometric arrangement of the temporary fiber ribbon 300 corresponds one-to-one with the order of the optical fibers in the system fusion splice pattern.

[0080] S3: Multi-core welding, heat shrink tubing installation and color sequence verification Reference Figure 4 The multi-core fusion splicer 210 is used to splice each group of temporary fiber optic ribbons 300 after fiber assembly and adhesive application in a single operation. The splicing sequence of the multi-core fusion splicer 210 is consistent with the sequence of the fiber optic assembly 200, ensuring that the temporary fiber optic ribbons 300 maintain their sequence during transfer from the fiber optic assembly 200 to the multi-core fusion splicer 210. After splicing, a multi-core fiber optic heat shrink tubing 310 is installed at the splice location to provide unified protection for the splice point of the group of fibers. Each group of fibers corresponds to one multi-core fiber optic heat shrink tubing 310, establishing a stable information chain of "group - temporary fiber optic ribbon 300 - splice point - multi-core fiber optic heat shrink tubing 310" from the beginning of grouping.

[0081] Between S3 and S4, color sequence verification is also included: the order of the two fibers at both ends of the temporary fiber ribbon 300 is checked to confirm the correct splicing order of the group of fibers. Since the position of the fiber assembler 200 corresponds one-to-one with the order of the system splicing pattern, and the geometric arrangement of the temporary fiber ribbon 300 has been solidified after being removed in S22, the entire group's order can be confirmed by checking the color sequence of the two fibers at both ends of the temporary fiber ribbon 300. If the color sequence of the two fibers at both ends is consistent with the pattern specification, then the color sequence of each fiber in the middle is also consistent. This verification method simplifies the traditional multi-core splicing process of checking each fiber after splicing, i.e., 12 times for each group of 12 cores, to checking the left and right ends, i.e., only 2 times for each group. After the color sequence verification is passed and all groups are confirmed to be free of misaligned fibers, the masking tape label 320 on each group of fibers is removed to prepare for the subsequent fiber coiling process in S4.

[0082] S4: Coil the multi-core fiber optic heat shrink tubing into the fiber tray and secure it. Reference Figure 5The fiber optic cables, after being spliced ​​and installed with the multi-core fiber heat shrink tubing 310, are coiled into the coiling area 111 of the fiber coiling tray 110. The coiling area 111 is enclosed by four guide pins 130.

[0083] The spliced ​​optical fibers are divided into left optical fiber group 410 and right optical fiber group 420 according to the two optical cable ends of the submarine optical cable 120 located on both sides of the submarine optical cable splice box 100. The left optical fiber group 410 starts from the left optical cable end 121, and the right optical fiber group 420 starts from the right optical cable end 122.

[0084] The left fiber optic group 410 is coiled: The left fiber optic group 410 is coiled counterclockwise around the inside of the four guide pins 130 for the first full turn. After coiling, a fiber separator 131 is installed on each of the guide pins 130 at both ends of the fiber tray 110. The second full turn is then coiled counterclockwise around the inside of the guide pins 130. After coiling, another fiber separator 131 is installed on each of the guide pins 130 at both ends. The fiber separator 131 serves as a physical isolation layer between adjacent coils, preventing interlayer compression. Both full turns of the left fiber optic group 410 are coiled counterclockwise, and the direction of the last half-turn of fiber directly leads to the left heat-shrink tubing mounting base 150, without the need for redirection by the P-type clip 140.

[0085] The right fiber optic group 420 is coiled: The right fiber optic group 420 is coiled counter-clockwise around the inside of the four guide pins 130 for the first full turn. This direction is consistent with the first full turn direction of the left fiber optic group 410, facilitating a uniform transition of the fiber from the cable end to the first turn. After coiling, a fiber separator 131 is installed on each of the guide pins 130 at both ends. The second full turn is then coiled clockwise around the inside of the guide pins 130, in the opposite direction to the first full turn direction of the right fiber optic group 420. After coiling, another fiber separator 131 is installed on each of the guide pins 130 at both ends.

[0086] After the second full-turn winding direction of the right fiber optic group 420 is switched relative to the first full-turn winding direction, the forward direction of the last half-turn of the fiber optic group 420 is aligned with the entry direction of the P-type clamp 140 set on the fiber tray 110, allowing the last half-turn of the fiber optic group to pass smoothly through the P-type clamp 140 without forced twisting. Under basic operating conditions, the total number of turns of both the left fiber optic group 410 and the right fiber optic group 420 is 4 full turns.

[0087] O-ring installation: Install O-rings on the four guide pins 130, with the O-rings positioned 3 to 4 millimeters from the top of the guide pin 130. This position allows the last half-loop of optical fiber to cross over from the top of the guide pin 130 into the P-clamp 140 without obstructing the P-clamp 140 fixing process.

[0088] P-clamp 140 fixing: Open the P-clamp 140, pass the last half-turn of fiber in the right fiber optic group 420 through the P-clamp 140, and fix the P-clamp 140 to the fiber tray 110 with an M4×10 countersunk screw coated with Loctite 222e at a torque of 0.6 Nm. The P-clamp 140 is only used to fix the last half-turn of fiber in the right fiber optic group 420; the left fiber optic group 410 does not need to pass through the P-clamp 140.

[0089] Fixing of multi-core fiber optic heat shrink tubing 310: Refer to Figure 6 After each group of optical fibers completes the coiling in step S4, the multi-core fiber heat shrink tubing 310 on each group of optical fibers is attached and fixed to the heat shrink tubing mounting base 150 using fasteners 160. The heat shrink tubing mounting base 150 is located outside the coiling area 111 of the fiber tray 110. Fasteners 160 include heat shrink tubing fastening tape, double-sided adhesive, and locking strips. First, heat shrink tubing fastening tape is placed on the heat shrink tubing mounting base 150 and fixed to the heat shrink tubing mounting base 150 and the bend limiter block with M3×12 screws at a torque of 1 Nm. Then, double-sided adhesive is adhered to the heat shrink tubing fastening tape. Finally, the multi-core fiber heat shrink tubing 310 is centered and attached to the double-sided adhesive. The predetermined number of multi-core fiber optic heat shrink tubes 310 that can be accommodated when the heat shrink tubing fastening tape is applied in a single layer is the integer part of the ratio of the width of the heat shrink tubing fastening tape to the diameter of the multi-core fiber optic heat shrink tube 310. In this embodiment, the predetermined number is 4. The multi-core fiber optic heat shrink tubes 310 are arranged in a single layer on the heat shrink tubing mounting base 150, and the upper limit of the number is this predetermined number. If the number of groups exceeds this predetermined number, the double-sided fiber coiling process is performed on the other side of the fiber coiling tray 110 to distribute the workload, see Embodiment 3.

[0090] The tightening direction of fastener 160 is adaptively determined based on the total number of turns of the left fiber optic group 410 and the right fiber optic group 420. Under basic operating conditions, the total number of turns of the left fiber optic group 410 and the right fiber optic group 420 is 4 full turns, i.e., an integer number of turns. Fastener 160 is tightened in a direction away from the winding surface 112, so that the multi-core fiber optic heat shrink tubing 310 is attached to the side of the heat shrink tubing mounting base 150 near the winding surface 112. After tightening in place, the locking strip is installed, and the locking strip is fixed with an M2.5×10 socket head cap screw coated with Loctite 222e at a torque of 0.6 Nm, and the excess part of the heat shrink tubing fastening tape is cut off.

[0091] After all the process steps in Example 1 are completed, taking a 48-core submarine optical cable 120 as an example, the total time for a single splice point process does not exceed 2 hours, and the time is correspondingly shortened when the number of cores is less. Compared with the total time of 6 to 8 hours for a single splice point in the single-core splicing process, more than 4 hours of work time is saved.

[0092] Example 2: Single-sided fiber discs with remelting margin under maximum operating conditions Example 2 describes the same core count range as Example 1, i.e., 24 to 48 cores, where multiple remelting allowances are needed or the weld quality is unstable. The difference between Example 2 and Example 1 lies in the upgrade of the cutting length setting and the reversal of the fastener 160 tensioning direction; the rest of the process is the same as in Example 1.

[0093] In Example 2, the predetermined cutting length is set to the second level, i.e., the maximum operating condition, with a predetermined cutting length of 995 mm. Correspondingly, the length of the second adhesive-coated section 302 in S2 is 150 mm. The length of the second adhesive-coated section 302 of 150 mm is calculated based on the cumulative cutting length of 4 remeltings (4 times × 30 mm = 120 mm), leaving a 30 mm margin so that each group of optical fibers can be remelted 4 times.

[0094] The winding path in Example 2 is the same as in Example 1, but due to the 150 mm increase in cutting length, the winding area 111 of the fiber tray 110 needs to accommodate an additional 150 mm of optical fiber. This extension is achieved by winding each fiber group for two full turns, followed by a half turn on each group. That is, the total number of turns for both the left fiber group 410 and the right fiber group 420 is 4 full turns plus a half turn.

[0095] Because the total number of coil turns changes from an integer number of turns to an integer number of turns plus half a turn, the entry position of the optical fiber into the heat shrink tubing installation area shifts upwards. Under basic operating conditions, the optical fiber end emerges from below the coiling area 111 of the fiber tray 110; under extended operating conditions, the optical fiber end emerges from above the coiling area 111. Therefore, the tightening direction of the fastener 160 is reversed accordingly. (Refer to...) Figure 6 In extended operating conditions, the fastener 160 is tightened towards the coiled surface 112, causing the multi-core fiber heat shrink tubing 310 to adhere to the side of the heat shrink tubing mounting base 150 opposite to the coiled surface 112. This reversal of the tightening direction prevents the double-sided adhesive from pressing against the upper fiber inlet, and avoids sharp bends in the fiber at the inlet that could cause additional optical loss.

[0096] The remaining steps of Example 2, including grouping, labeling, fiber arrangement, welding, heat shrink tubing installation, color sequence verification, O-ring installation, P-clamp 140 fixing, and locking strip fixing, are exactly the same as those in Example 1.

[0097] Example 3: 50 to 96 core double-sided fiber coiling process Example 3 describes a scenario where the total number of optical fibers in the submarine optical cable 120 exceeds the single-sided capacity threshold, i.e., the total number of optical fibers is greater than 48 but not more than 96. In this example, the single-sided capacity threshold is 48 cores, corresponding to the maximum total number of optical fibers that can be accommodated in a single-sided fiber coil. Specifically, the single-sided heat-shrinkable tubing fastening tape can accommodate a predetermined number of four multi-core optical fiber heat-shrinkable tubes 310, and the multi-core fusion splicer 210 has a splicing capacity of 12 cores per cycle. The product of these two is 48 cores, therefore the single-sided capacity threshold is 48 cores.

[0098] When the total number of optical fibers in a submarine optical cable 120 exceeds 48, the optical fibers are divided into front optical fiber groups and back optical fiber groups. The total number of optical fibers in the front optical fiber group does not exceed 48, and the total number of optical fibers in the back optical fiber group also does not exceed 48. For example, for a 96-core submarine optical cable 120, it is divided into 8 groups of 12 fibers each. The first to fourth groups, totaling 48 cores, are the front optical fiber groups, and the fifth to eighth groups, totaling 48 cores, are the back optical fiber groups.

[0099] The grouping in S1 covers all the fibers shared by the front and back fiber groups. This is a key constraint of the double-sided fiber coiling process. The disassembly and grouping of the submarine optical cable 120 occurs only once for a single submarine optical cable 120. The grouping action must be completed once at the start of the process, dividing all the fibers. There is no situation where the grouping is re-executed on the back fiber group.

[0100] The front fiber optic group undergoes all processes S1 to S4 on the front side of the fiber tray 110. The back fiber optic group undergoes all processes S2 to S4 on the back side of the fiber tray 110. The back fiber optic group does not need to repeat S1 because the grouping in S1 was completed in one step during the front process. The winding direction arrangement in S4 of the back fiber optic group is the same as that of the front fiber optic group; that is, the back fiber optic group also uses a winding direction of two counter-clockwise turns on the left, one counter-clockwise turn on the right, and one clockwise turn on the right.

[0101] The processes for the front fiber optic assembly and the back fiber optic assembly are performed in a staggered sequence as follows: First, complete all processes S1 to S4 for the front fiber optic assembly, including fixing the P-type clip 140 of the front fiber optic assembly. After completing all processes for the front fiber optic assembly, flip the fiber tray 110 so that its back side faces upward as the new operating surface. Then, perform all processes S2 to S4 on the back side of the fiber tray 110 for the back fiber optic assembly, including fixing the P-type clip 140 of the back fiber optic assembly.

[0102] The structural components on the fiber optic tray 110 are divided into shared front and back structural components and independent structural components. The shared front and back structural components are first installed in the center of the fiber optic tray 110 during the front fiber assembly process, i.e., the middle position between the front and back sides. In this embodiment, the shared front and back structural components include a bend limiting block and a heat shrink tubing mounting base 150. The bend limiting block is fixed to the center of the fiber optic tray 110 with an M3×12 screw and a torque of 1 Nm, so that the shared structural components only need to be installed once in the double-sided process.

[0103] The independent structural components of the front fiber optic group are installed on the front side of the fiber optic tray 110 during the front fiber optic group manufacturing process, while the independent structural components of the back fiber optic group are installed on the back side of the fiber optic tray 110 during the back fiber optic group manufacturing process. In this embodiment, the independent structural components include heat-shrink tubing fastening tape, locking strips, O-rings, and P-clamps 140. The front and back independent structural components are installed separately from their respective sides of the fiber optic tray 110, ensuring that the independent structural components of the front and back fiber optic groups do not interfere with each other spatially.

[0104] The sequential execution of the front and back processes allows operators to focus on only one side at each stage, avoiding conflicts between fiber optic crossovers and structural screws when operating on both sides in parallel.

[0105] Example 4: Process Degradation Response to Welding Failure under Extreme Conditions Example 4 describes an extreme case in S3 where the fusion splicing of a group of optical fibers fails after reaching the number of re-fusion cycles allowed for that group. For example, under the first basic condition, the group of optical fibers fails to splice after 3 re-fusion cycles; or under the second maximum condition, the group of optical fibers fails to splice after 4 re-fusion cycles. In this case, the following three-level process degradation response is initiated for the group of optical fibers, with the three levels unfolding in a progressive relationship.

[0106] Before the Level 3 process degradation response, if a group of optical fibers in S3 has a single or partial fiber fusion failure while the remaining fibers are fused successfully, a single-fiber refusion process is performed as a pre-treatment. The single-fiber refusion process includes the following steps: detaching the single or partial fiber with the failed fusion from the multi-core fiber heat shrink tubing 310; re-fusion the single or partial fiber with the failed fusion; installing a single-core fiber heat shrink tubing at the re-fusion location of the single or partial fiber with the failed fusion; and clamping and fixing the single-core fiber heat shrink tubing between the multi-core fiber heat shrink tubing 310s. The single-fiber refusion process only targets the failed fiber in that group and does not affect the status of the multi-core fiber heat shrink tubing 310 for the remaining fused fibers in that group. After single-fiber refusion, if all fibers in the group are fused successfully, the process continues to the S4 fiber coiling process; if single-fiber refusion still fails, the fiber in that group is processed according to the Level 3 process degradation response. The judgment condition applicable to the single-fiber refusion process is: the number of unsuccessful fusion fibers in the group is less than half of the total number of cores in the group, that is, the number of qualified fusion fibers retained in the multi-core fiber heat shrink tube 310 after single-fiber refusion accounts for the majority.

[0107] First, the first-level response is executed: the second adhesive-coated section 302 of the fiber group is stripped, and the second adhesive coating is re-executed on the fiber group. The length of the second adhesive-coated section 302 and the predetermined cutting length are adopted according to the corresponding values ​​of adjacent grades in the synchronous setting relationship, so that the fiber group obtains the number of repeatable splicing times corresponding to the adjacent grade. The first-level response is physically executed in one of two directions. The first direction is the grade-up direction: if the fiber group has reserved the slack fiber required for extension cutting in S1, then the fiber group is extended from the predetermined cutting length of the current grade to the predetermined cutting length of the adjacent higher grade. The second direction is the grade-down direction: if the fiber group has been cut to the predetermined cutting length of the current grade in S1 and there is no extension slack, then the fiber group is shortened from the predetermined cutting length of the current grade to the predetermined cutting length of the adjacent lower grade. For example, if the fiber group has already used the second tier as its entry tier in S1 (i.e., the second coated section 302 is 150 mm long, the predetermined cut length is 995 mm, and it can be re-fused 4 times), but the splicing still fails, then the first-level response executes in the downgrading direction, cutting the fiber group to the predetermined cut length of the first tier (845 mm) and the length of the second coated section 302 (100 mm), allowing the fiber group to continue utilizing the remaining splicing opportunities of the three re-fused times corresponding to the first tier. As another example, if the fiber group uses the first tier in S1 and S1 has reserved fiber slack for extension cutting, then the first-level response executes in the upgrading direction, extending the fiber group to the predetermined cut length of the second tier (995 mm) and the length of the second coated section 302 (150 mm), obtaining additional re-fused times. If the fiber group has already used the first tier in S1 and there is no fiber slack for extension in S1, then the first-level response cannot be executed, and it directly proceeds to the second-level response. The first-level response executes at most once.

[0108] If the splicing of the fiber group still fails after the first-level response, the second-level response is executed: the fiber group is removed from the fiber assembler 200. The grouping in S1 of the fiber group is retained, meaning the fiber group still belongs to the original group, and the group identification remains valid; the predetermined cutting length corresponding to the position of the fiber group at the time of completion of the first-level response is also retained. S2 is re-executed for the fiber group, including re-arranging the fiber, re-applying the first adhesive coating section 301 and the second adhesive coating section 302, and re-executing S3, including re-splicing and reinstalling the multi-core fiber heat shrink tubing 310. The second-level response eliminates problems such as incorrect fiber assembler 200 sequence, fiber end face contamination, and incomplete adhesive coating in the first section by re-executing the fiber arrangement action.

[0109] If the fusion splicing of this group of optical fibers still fails after the second-level response, a third-level response is executed: the group of optical fibers is marked as faulty and temporarily stored outside the fiber tray 110. The processes for the remaining normal groups continue according to the main flow. After all S1 to S4 for the remaining groups are completed, S2 to S4 are re-executed for the faulty group using spare fiber segments. The spare fiber segments are the reserved surplus fiber segments in the submarine optical cable 120 or specially configured spare fusion splicing fibers. The color sequence of the spare fiber segments is consistent with the color sequence of the faulty group, so that the role of the faulty group in the system fusion splicing pattern is maintained. The third-level response avoids a single group failure from disrupting the overall process sequence, reducing the impact of the failure on the project schedule from the scrapping of the entire group to a delay of a single group.

[0110] After three levels of process degradation response, the overall process success rate of the method in this application is improved to nearly 100%.

[0111] Example 5: Typical Chip Count Application Comparison Example 5 provides a comparative application of the method of this application in submarine optical cables 120 with different typical core counts, as a supplementary explanation to Examples 1 to 4. For each typical core count, depending on whether multiple remelting margins need to be reserved on site, the first basic working condition or the second maximum working condition is selected. For specific configurations, please refer to Examples 1 and 2.

[0112] 24-core submarine optical cable 120: Divided into 2 groups of 12 cores each, a total of 24 optical fibers are obtained. The total number of optical fibers is 24, which does not exceed the single-sided capacity threshold of 48 cores. Single-sided fiber coiling is used, and the process is carried out according to Example 1 or Example 2.

[0113] 48-core submarine optical cable 120: Divided into 4 groups of 12 cores each. The total number of optical fiber cores, 48, is equal to the single-sided capacity threshold. Single-sided fiber coiling is used, and the process is carried out according to Example 1 or Example 2.

[0114] 72-core submarine optical cable 120: Divided into 6 groups of 12 cores each. The total number of optical cores is 72, which exceeds the single-sided capacity threshold of 48 cores, so double-sided fiber coiling is used. The first to fourth groups, totaling 48 cores, are used as the front optical fiber group, and the fifth and sixth groups, totaling 24 cores, are used as the back optical fiber group, and the process is carried out according to Example 3.

[0115] 96-core submarine optical cable 120: Divided into 8 groups of 12 cores each. The total number of optical cores, 96, exceeds the single-sided capacity threshold, so double-sided fiber coiling is used. The first to fourth groups, totaling 48 cores, are used as the front optical fiber groups, and the fifth to eighth groups, totaling 48 cores, are used as the back optical fiber groups, following the process of Example 3.

[0116] For each typical core count application, the total process time for a single splice point using the method of this application does not exceed 2 hours. Compared with the total time of 6 to 8 hours for a single splice point of a 120-core submarine optical cable with the same core count in the single-core splicing process, the method of this application saves more than 4 hours of work time.

[0117] The above descriptions are specific embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural modifications made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A process and fiber coiling method for multi-core fusion splicing in submarine optical cable splice boxes, characterized in that, Includes the following steps: S1. At the splicing site of the submarine optical cable splice box, the optical fibers disassembled from the submarine optical cable are grouped according to the one-time splicing capacity of the multi-core fusion splicer to obtain multiple groups of optical fibers, and each group of optical fibers is cut according to the predetermined cutting length. S2. Perform fiber assembly and adhesive application on each group of optical fibers in sequence to bond the group of optical fibers into a temporary optical fiber ribbon. The fiber assembly is to arrange the group of optical fibers side by side according to a predetermined arrangement rule using a fiber assembly device. The adhesive application is to apply optical fiber adhesive to the arranged section of the group of optical fibers. S3. Use a multi-core fusion splicer to splice each set of temporary optical fiber ribbons after fiber arrangement and gluing in one go, and install multi-core optical fiber heat shrink tubing at the splice position; S4. Coil each group of optical fibers that have completed fusion splicing and multi-core fiber heat shrink tubing installation into the coiling area of ​​the fiber coiling tray, and fix the multi-core fiber heat shrink tubing on each group of optical fibers to the heat shrink tubing mounting base outside the coiling area.

2. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 1, characterized in that, The adhesive application in S2 includes a first adhesive application and a second adhesive application: The first section of adhesive is applied to the fiber optic cable inside the fiber optic cable assembly device to apply fiber optic adhesive to the group of optical fibers that have been assembled. The length of the first section of adhesive on the group of optical fibers is such that the group of optical fibers maintains a ribbon shape after being taken out of the fiber optic cable assembly device. The second adhesive segment is applied after the group of optical fibers is taken out of the fiber optic assembly. The length of the second adhesive segment is greater than the length of the first adhesive segment and corresponds to the number of times the group of optical fibers can be repeatedly spliced.

3. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 2, characterized in that, The length of the second adhesive application segment and the predetermined cutting length in S1 are synchronously set according to the number of times the fiber can be repeatedly melted. Each increase in the number of times the fiber can be repeatedly melted constitutes a step in the synchronous setting relationship. The length of the second adhesive coating is calculated based on the number of times the fiber can be repeatedly spliced. For each increase in the number of times the fiber can be repeatedly spliced, the increase in the length of the second adhesive coating is not less than the fiber cut-off length after a single splicing. The predetermined cutting length is calculated based on the coiling allowance corresponding to the number of times the fiber can be repeatedly fused. For each increase in the number of times the fiber can be repeatedly fused, the predetermined cutting length increases synchronously, thereby increasing the coiling allowance in the coiling area of ​​the fiber tray to accommodate the extended optical fiber.

4. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 2, characterized in that, The first and second adhesive coatings are both located on the optical fiber within a straight section outside the coiling area of ​​the fiber tray. In S4, the portion of each group of optical fibers coiled into the coiling area is the uncoated optical fiber segment in each group of optical fibers; The straight section containing the first and second adhesive coatings does not overlap physically with the coiled section in S4 that is coiled into the coiled area.

5. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 1, characterized in that, The predetermined arrangement rule in S2 ensures that the position of each optical fiber in the fiber optic cable corresponds one-to-one with the order of the group of optical fibers specified in the system fiber optic splicing diagram, and the geometric arrangement of the temporary fiber optic ribbon after the adhesive coating is completed corresponds one-to-one with the order of the group of optical fibers in the system fiber optic splicing diagram. In S3, the welding sequence of the multi-core fusion splicer is consistent with the sequence of the fiber output device; Between S3 and S4, the process further includes: verifying the correct order of fiber optic splicing by checking the order of the two fibers at both ends of the temporary fiber optic band.

6. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 1, characterized in that, In step S4, the winding of each group of optical fibers into the winding area of ​​the fiber tray is performed according to the following directional arrangement rules: The fiber tray has a winding surface that serves as the surface where the winding area is located, and each group of optical fibers is wound within the winding area where the winding surface is located. The spliced ​​optical fibers are divided into left optical fiber group and right optical fiber group according to the two optical cable ends located on both sides of the submarine optical cable splice box. The left optical fiber group is continuously coiled a predetermined number of times in the same coiling direction within the coiling area; The right optical fiber group is wound in the same winding direction as the left optical fiber group in the first turn within the winding area, and then switches to the opposite winding direction from the second turn onwards. By switching the winding direction of the right fiber optic group, the forward direction of the last half-turn of the right fiber optic group is aligned with the inlet direction of the end fixing member provided on the fiber optic tray, and the last half-turn of the fiber optic group is fixed to the fiber optic tray by the end fixing member.

7. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 6, characterized in that, In step S4, the multi-core optical fiber heat shrink tubing is fixed to the heat shrink tubing mounting base in the following manner: After each group of optical fibers completes the coiling in S4, the multi-core optical fiber heat shrink tubing is attached and fixed to the heat shrink tubing mounting base using fasteners. The tensioning direction of the fastener is adaptively determined based on the total number of turns of the left and right fiber optic groups respectively: In response to the fact that the total number of turns of the left fiber group and the right fiber group is an integer, the fastener is pulled away from the winding surface, so that the multi-core fiber heat shrink tubing is attached to the side of the heat shrink tubing mounting base near the winding surface. In response to the total number of turns of the left and right fiber groups being an integer plus half a turn, the fastener is pulled towards the winding surface, so that the multi-core fiber heat shrink tubing is attached to the side of the heat shrink tubing mounting base opposite to the winding surface.

8. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 1, characterized in that, Based on the comparison between the total number of optical fibers in the submarine optical cable and the single-sided capacity threshold, either single-sided or double-sided fiber coiling is selected: In response to the total number of optical fibers in the submarine optical cable not exceeding the single-sided capacity threshold, steps S1 to S4 are performed on the front side of the fiber reel tray; In response to the total number of optical fibers in the submarine optical cable exceeding the single-sided capacity threshold, the optical fibers are divided into a front optical fiber group and a back optical fiber group. The total number of optical fibers in the front optical fiber group does not exceed the single-sided capacity threshold. The grouping in S1 covers all the optical fibers common to both the front optical fiber group and the back optical fiber group. The front optical fiber group performs S1 to S4 on the front side of the fiber tray, and the back optical fiber group performs S2 to S4 on the back side of the fiber tray. The winding direction arrangement in S4 of the back fiber optic group is the same as that in S4 of the front fiber optic group.

9. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 8, characterized in that, If the total number of optical fibers in the submarine optical cable exceeds the single-sided capacity threshold, the processes for the front optical fiber assembly and the back optical fiber assembly shall be performed in a staggered sequence as follows: Complete all steps S1 to S4 of the front optical fiber assembly; After completing all the processes of the front fiber optic group, the fiber tray is flipped over so that the back of the fiber tray faces upward as a new operating surface. All steps S2 to S4 are performed on the back of the fiber optic group on the back side of the fiber tray; The structural components on the fiber optic tray are divided into shared structural components on both sides and independent structural components. The shared structural components on both sides are first installed in a predetermined position during the process stage of the front fiber optic group. The independent structural components of the front fiber optic group are installed on the front side of the fiber optic tray during the process stage of the front fiber optic group. The independent structural components of the back fiber optic group are installed on the back side of the fiber optic tray during the process stage of the back fiber optic group.

10. The process and fiber coiling method for using multi-core fusion splicing in a submarine optical cable splice box according to claim 3, characterized in that, If, in step S3, the fusion splicing of a certain group of optical fibers fails after reaching the number of repeatable splicing attempts, the following three-level process degradation response is initiated for that group of optical fibers: Level 1 response: Strip the second section of adhesive from the group of optical fibers, re-apply the second section of adhesive to the group of optical fibers, and adopt the corresponding value of the next level in the synchronization setting relationship, so that the number of repeatable fiber splicing is increased accordingly; Second-level response: If the fusion splicing of the fiber group still fails after the first-level response, the fiber group is removed from the fiber assembler, retaining the grouping in S1 and the predetermined cutting length used in the first-level response, and S2 and S3 are re-executed for the fiber group. Level 3 response: If the fusion splicing of this group of optical fibers still fails after the Level 2 response, the group of optical fibers is marked as a faulty group and temporarily stored outside the fiber tray. After all the steps S1 to S4 of the remaining groups are completed, steps S2 to S4 are re-executed for the faulty group using a spare fiber segment.

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