Multi-core fiber coupling connection method

Abstract

The application provides a multi-core optical fiber coupling connection method, taking a multi-core optical fiber, using an HF acid corrosion solution to gradually corrode each multi-core optical fiber core from the end face of the multi-core optical fiber to form a plurality of multi-core optical fiber core corrosion holes; taking a single-mode optical fiber, using the HF acid corrosion solution to corrode the cladding of the single-mode optical fiber from the outside to the inside to the outer wall of the single-mode optical fiber core to form a plurality of single-mode optical fiber bare cores; inserting each single-mode optical fiber bare core into each multi-core optical fiber core corrosion hole, and making the end face of the single-mode optical fiber bare core abut against the end face of the multi-core optical fiber core at the bottom end of the multi-core optical fiber core corrosion hole; filling a solidified glue into the multi-core optical fiber core corrosion hole, and waiting for the solidified glue to completely solidify, thereby solving the problem of coupling connection of the split single-mode optical fiber core and the multi-core optical fiber.

Description

Technical Field

[0001] This invention relates to the field of multi-core optical fiber coupling technology, and in particular to a multi-core optical fiber coupling connection method. Background Technology

[0002] With the rapid development of network and broadband services, Internet traffic has been growing at a rate of about 10 times every 4 years since 2000. In order to meet the growth rate of demand, researchers have adopted advanced technologies such as optical bandwidth expansion of transmission window, enhanced spectral efficiency, and wavelength division multiplexing, which have enabled the transmission capacity of conventional single-mode single-core optical fiber to reach 100Tb / s, but this is already the nonlinear Shannon limit of existing technology.

[0003] In the digital economy era, with the increasing maturity and commercialization of 5G technology, the demand for data is surging, and capacity constraints are expected to emerge in the near future. Multi-core optical fibers offer a new perspective to address this data service bottleneck. From a spatial division multiplexing perspective, multiple spatial paths can be introduced into optical fibers, merging multiple independent fiber cores into a single fiber. The transmission capacity of the fiber increases exponentially with the number of fiber cores. Multi-core optical fibers can also enable multi-dimensional information fiber optic sensing, supporting large-scale, wide-area intelligent sensing and monitoring networks, such as the Internet of Things and digital twin cities.

[0004] However, multi-core optical fibers are a type of microstructured special optical fibers. Their unique structure makes it difficult to apply them simply, quickly, and conveniently to communication networks and optical fiber sensor network systems. Therefore, high-performance multi-core optical fiber coupling technology and preparation methods are particularly important and are the core technologies for promoting the application of multi-core optical fibers and reducing costs.

[0005] In related multi-core fiber coupling technologies, methods such as tapered coupling, lens coupling, and polymer waveguides are affected by processing accuracy, resulting in low fiber geometric alignment accuracy. This increases the insertion loss of multi-core fiber coupling devices and reduces the performance of their key indicators. Summary of the Invention

[0006] This invention provides a multi-core optical fiber coupling connection method to solve the problem of coupling connection between the core of a split single-mode optical fiber and a multi-core optical fiber.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a multi-core optical fiber coupling connection method.

[0008] Take a multi-core optical fiber and use an HF acid etching solution to gradually etch each multi-core optical fiber core from the end face of the multi-core optical fiber to form multiple multi-core optical fiber core etching holes.

[0009] Take a single-mode optical fiber and use an HF acid etching solution to etch the cladding of the single-mode optical fiber from the outside to the inside until it is close to the outer wall of the single-mode optical fiber core to form multiple bare single-mode optical fiber cores.

[0010] Insert each single-mode fiber bare core into the etching hole of each multi-core fiber core, so that the end face of the single-mode fiber bare core is aligned with the end face of the multi-core fiber core at the bottom of the etching hole.

[0011] Fill the etched holes in the multi-core optical fiber core with curing adhesive and wait for the adhesive to fully cure.

[0012] In a preferred embodiment, an auxiliary etching sleeve is included. The auxiliary etching sleeve has a connecting part that is slidably connected to the outer wall of the multi-core optical fiber. The auxiliary etching sleeve has multiple auxiliary etching capillaries with the same distribution as the multi-core optical fiber cores. Each auxiliary etching capillary is aligned with each multi-core optical fiber core. The connector between the multi-core optical fiber and the auxiliary etching sleeve is erected, with the auxiliary etching sleeve located at the upper end. An HF acid etching solution is added to each auxiliary etching capillary to etch the multi-core optical fiber core. The auxiliary etching capillary moves downward as the etching depth increases until the etching depth reaches a set depth, after which the HF acid etching solution is poured out.

[0013] In a preferred embodiment, an etchant container is included, which contains an HF acid etching solution. A sealing adhesive layer is applied to the bare end of the single-mode fiber core. The single-mode fiber is then inserted downward into the etchant container to a set depth. When the cladding of the etchant container is etched by the HF acid solution to near the outer wall of the bare single-mode fiber core, the single-mode fiber is extracted.

[0014] In a preferred embodiment, a connecting guide sleeve is provided, the connecting guide sleeve is provided with a groove, and the bottom end of the groove is provided with multiple single-mode fiber jacks with the same distribution as the multi-core fiber cores, the single-mode fiber jacks being a through structure; the multi-core fiber end is sleeved in the groove, each single-mode fiber is inserted into the single-mode fiber jack, and each single-mode fiber bare fiber core is inserted into the etched hole of each multi-core fiber core.

[0015] In the preferred embodiment, each single-mode fiber jack has a blind slot on its sidewall, which is connected to the recess. The bottom of the recess is also provided with an adhesive inlet groove and an adhesive guiding branch groove connected to the adhesive inlet groove. The adhesive inlet groove and the adhesive guiding branch groove are connected to the single-mode fiber jack. The outer wall of the connecting sleeve is provided with an adhesive inlet hole and an overflow hole. The two ends of the adhesive inlet hole and the overflow hole are respectively connected to the two ends of the adhesive inlet groove. A plug is installed in the overflow hole. Curing adhesive is injected into the connecting sleeve through the adhesive inlet hole. The curing adhesive fills the gap between the single-mode fiber core and the multi-core fiber core, the gap between the bottom of the recess and the end face of the multi-core fiber, and the blind slot of the jack until the plug in the overflow hole is pushed out, and the adhesive injection stops.

[0016] The beneficial effects of this invention are as follows: it uses processed split optical fibers to be directly inserted into the core holes of multi-core optical fibers, which has a high-precision geometric distribution and solves the most critical geometric alignment problem in the fabrication of multi-core optical fiber couplers; it does not require tapering to solve problems such as mode field or outer diameter size mismatch, which can further reduce the insertion loss caused by geometric alignment deviation; the fabrication is simple and the operation is repeatable, the structure is compact, and it is conducive to engineering research. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a schematic diagram of the multi-core optical fiber of the present invention.

[0019] Figure 2 This is a schematic diagram of the single-mode optical fiber of the present invention.

[0020] Figure 3 This is a schematic diagram of the corrosion of the multi-core optical fiber core of the present invention.

[0021] Figure 4 This is a schematic diagram of the single-mode fiber cladding corrosion of the present invention.

[0022] Figure 5 This is a schematic diagram of the use of the connecting guide sleeve of the present invention.

[0023] Figure 6 This is a structural diagram of the auxiliary corrosion sleeve of the present invention.

[0024] Figure 7 This is a structural diagram of the connecting guide sleeve of the present invention.

[0025] In the figure: multi-core optical fiber 1; multi-core optical fiber core etching hole 101; multi-core optical fiber core 102; single-mode optical fiber 2; single-mode optical fiber bare core 201; single-mode optical fiber core 202; sealing adhesive layer 203; connecting guide sleeve 3; adhesive inlet hole 301; adhesive inlet groove 302; adhesive guide branch groove 303; jack blind groove 304; adhesive overflow hole 305; single-mode optical fiber jack 306; recess 307; auxiliary etching sleeve 4; auxiliary etching capillary 401; socket part 402; etching liquid container 5. Detailed Implementation

[0026] Example 1:

[0027] like Figure 1-7 In this paper, a multi-core optical fiber coupling connection method is described.

[0028] Take a multi-core optical fiber 1, and use an HF acid etching solution to gradually etch each multi-core optical fiber core 102 from the end face of the multi-core optical fiber 1 to form multiple multi-core optical fiber core etching holes 101.

[0029] Take a single-mode fiber 2 and use an HF acid etching solution to etch the cladding of the single-mode fiber 2 from the outside to the inside until it is close to the outer wall of the single-mode fiber core 202 to form multiple single-mode fiber bare cores 201.

[0030] Insert each single-mode fiber bare core 201 into each multi-core fiber core etching hole 101, so that the end face of the single-mode fiber bare core 201 is aligned with the end face of the multi-core fiber core 102 at the bottom of the multi-core fiber core etching hole 101.

[0031] Fill the core etching holes 101 of the multi-core optical fiber with curing adhesive and wait for the adhesive to fully cure.

[0032] In a preferred embodiment, an auxiliary etching sleeve 4 is included. The auxiliary etching sleeve 4 has a sleeve portion 402, which is slidably sleeved with the outer wall of the multi-core optical fiber 1. The auxiliary etching sleeve 4 has multiple auxiliary etching capillaries 401 distributed in the same manner as the multi-core optical fiber cores 102. Each auxiliary etching capillary 401 is aligned with each multi-core optical fiber core 102, and the connector between the multi-core optical fiber 1 and the auxiliary etching sleeve 4 is erected, with the auxiliary etching sleeve 4 located at the upper end. An HF acid etching solution is added to each auxiliary etching capillary 401 to etch the multi-core optical fiber core 102. The auxiliary etching capillary 401 moves downward as the etching depth increases until the etching depth reaches a set depth, after which the HF acid etching solution is poured out.

[0033] The auxiliary corrosion capillary 401 does not react with the HF acid corrosion solution. The inner diameter of the auxiliary corrosion capillary 401 is the same as the outer diameter of the multi-core fiber core 102. The wall thickness of the auxiliary corrosion capillary 401 is relatively thin. When the HF acid corrosion solution corrodes the multi-core fiber core 102, the inner diameter of the corrosion hole 101 formed in the multi-core fiber core is slightly larger than that of the multi-core fiber core 102, and is the same as the outer diameter of the auxiliary corrosion capillary 401. Under the action of gravity, the auxiliary corrosion sleeve 4 will automatically descend as the hole depth increases, continuously protecting the inner wall of the corroded hole, preventing the HF acid corrosion solution from spreading outward, and ensuring that the HF acid corrosion solution corrodes downward.

[0034] In a preferred embodiment, an etchant container 5 is included, which contains an HF acid etching solution. A sealing adhesive layer 203 is applied to the end of the bare single-mode fiber core 201. The single-mode fiber 2 is inserted downward into the etchant container 5 to a set depth. When the cladding of the etchant container 5 is etched by the HF acid solution to near the outer wall of the bare single-mode fiber core 201, the single-mode fiber 2 is pulled out.

[0035] Since the inner diameter of the corrosion hole 101 in the multi-core optical fiber is slightly larger than that of the multi-core optical fiber core 102, a thinner cladding layer can remain on the outside of the bare optical fiber core 201 to prevent the core from being corroded.

[0036] In a preferred embodiment, a connecting guide sleeve 3 is included. The connecting guide sleeve 3 is provided with a groove 307. The bottom end of the groove 307 is provided with multiple single-mode fiber jacks 306 that are distributed in the same way as the multi-core fiber cores 102. The single-mode fiber jacks 306 are through structures. The end of the multi-core fiber 1 is sleeved in the groove 307, and each single-mode fiber 2 is inserted into the single-mode fiber jack 306 and each single-mode fiber bare fiber core 201 is inserted into the etched hole 101 of each multi-core fiber core.

[0037] Before inserting the bare single-mode fiber core 201, the sealing adhesive layer 203 needs to be cleaned off.

[0038] In a preferred embodiment, each single-mode fiber optic jack 306 has a blind slot 304 on its sidewall, which is connected to the recessed slot 307. The bottom of the recessed slot 307 is also provided with an adhesive inlet groove 302 and an adhesive guiding branch groove 303 connected to the adhesive inlet groove 302. The adhesive inlet groove 302 and the adhesive guiding branch groove 303 are connected to the single-mode fiber optic jack 306. The outer wall of the connecting guide sleeve 3 is provided with an adhesive inlet hole 301 and an overflow hole 305. The two ends of the adhesive inlet hole 301 and the overflow hole 305 are respectively connected to the two ends of the adhesive inlet groove 302. A plug is installed in the overflow hole 305. Curing adhesive is injected into the connecting guide sleeve 3 through the adhesive inlet hole 301. The curing adhesive fills the gap between the single-mode fiber core 202 and the multi-core fiber core 102, the gap between the bottom of the recessed slot 307 and the end face of the multi-core fiber 1, and the blind slot 304 until the plug in the overflow hole 305 is pushed out, and the adhesive injection stops.

[0039] After the curing adhesive solidifies, not only are the fiber cores bonded together, but the connection between the ends of the multi-core fiber 1 and the single-mode fiber 2 is also bonded together, eliminating the need for other fixing connectors.

[0040] Example 2:

[0041] A method for fabricating multi-core optical fiber coupling includes processing multi-core optical fiber, processing single-mode optical fiber, and connecting guide sleeve. The processing of multi-core optical fiber involves etching or drilling away a certain distance from the core of the multi-core optical fiber using methods such as HF etching or laser drilling. The processing of single-mode optical fiber involves removing a certain distance of the cladding using etching. The connection method for each component is as follows: the exposed core of the processed single-mode optical fiber is inserted into the hole after the core of the processed multi-core optical fiber has been etched, and then a curing adhesive and connecting guide sleeve are used for fixation and encapsulation to form a multi-core optical fiber "fan-in / fan-out device".

[0042] A multi-core optical fiber is a multi-core optical fiber with n cores, where n is not less than 1. Its fiber cladding diameter is D, its core diameter is Dc, and its core spacing is Hc.

[0043] The fabrication process for multi-core optical fibers involves using an auxiliary porous sleeve with the same hole distribution as the fiber core. The auxiliary porous sleeve and the multi-core fiber are spliced ​​together and placed vertically. Then, HF acid solution is injected into the holes of the porous capillary, and after etching for a certain period, the multi-core fiber is processed into a multi-core fiber with a certain length of coreless region. Alternatively, laser drilling can be used to precisely locate the fiber core position and drill holes to create a coreless section of a certain depth, with the hole diameter matching the original fiber core diameter.

[0044] The porous sleeve consists of n holes (the same as the number of cores in a multi-core optical fiber), and the arrangement of the holes is the same as the arrangement of the cores in the multi-core optical fiber. The diameter of the porous capillary is D, and the diameter of the holes is Dc+2μm.

[0045] Single-mode fiber, as opposed to multi-core fiber, has the same core diameter and mode field as its multi-core counterpart, but a cladding diameter of 2Hc, which is twice the core spacing of the multi-core fiber. The single-mode fiber is fabricated using HF etching to remove 2cm of cladding. First, the single-mode fiber is sealed with adhesive. Then, it is placed vertically in an HF acid solution for a certain period to remove the cladding (the core portion remains). The length of cladding removed is the same as the coreless length of the multi-core fiber. The adhesive at the core is then removed using an adhesive remover to form the fabricated single-mode fiber. Alternatively, the cladding can be removed by polishing. The number of single-mode fibers produced is the same as the number of cores in the multi-core fiber.

[0046] The connecting guide sleeve is a capillary tube or quartz tube that is thinner in the middle and thicker at both ends, which serves to fix and encapsulate. The minimum diameter of the cone region is determined by the outer diameter of the bundled single-mode fiber after combining the fiber cores of the multi-core fiber. The length of the cone region is related to the core corrosion length of the multi-core fiber and the cladding length of the processed single-mode fiber, and should be slightly greater than the sum of the two.

[0047] Includes the following steps:

[0048] Step 1: Fabrication of multi-core optical fiber. An auxiliary porous sleeve with the same hole distribution as the multi-core fiber core is used. The auxiliary porous sleeve and the multi-core fiber are spliced ​​together and placed vertically. HF acid etching solution is then added to the holes of the porous sleeve for etching. After a period of etching, the multi-core fiber is processed into a multi-core fiber with a certain length of coreless region. Alternatively, laser drilling can be used to precisely locate the core position of the multi-core fiber, drilling a hole to a certain depth of coreless section, with the hole diameter matching the original core diameter.

[0049] Step Two: First, seal the single-mode fiber with adhesive. Then, place the single-mode fiber vertically in an HF acid solution for a certain period of time to remove the cladding (the core remains). The length of cladding removal is the same as the length of the coreless multi-core fiber. Next, remove the adhesive from the core area using an adhesive remover to form the processed single-mode fiber. Alternatively, the cladding can be removed by polishing the cladding portion with a polishing machine. The number of processed single-mode fibers is the same as the number of cores in the multi-core fiber.

[0050] Step 3: Encapsulation and fixation. Insert the exposed core of the processed single-mode fiber into the hole after the core of the processed multi-core fiber has been etched, and then fix and encapsulate it with curing adhesive and connecting sleeve.

[0051] Multi-core optical fibers are fabricated using the HF etching method. A porous capillary is fused and fixed to the end face of the multi-core optical fiber. The holes in the capillary are aligned with the fiber cores in terms of spacing and size, ensuring one-to-one alignment. Then, HF acid solution is injected into the holes in the capillary, and etching is performed for approximately 10 minutes, resulting in a 2cm coreless region in the multi-core optical fiber. Alternatively, multi-core optical fibers can be fabricated using laser drilling, directly drilling 2cm holes at the fiber core location with a diameter matching the original core diameter to completely remove the 2cm core. Single-mode optical fibers are fabricated using the HF etching method. To remove the 2cm cladding, first, seal the single-mode fiber with adhesive, then place the single-mode fiber vertically in an HF acid solution for about 10 minutes to remove the 2cm cladding (the core remains) to form a processed single-mode fiber. Then, remove the adhesive from the core area using an adhesive remover. The processed single-mode fiber can also be removed by grinding. The cladding is removed by grinding the cladding part with a grinding machine. The connection method of each component in this invention is as follows: insert the exposed core of the processed single-mode fiber into the hole after the core of the processed multi-core fiber has been etched, and then fix and encapsulate it with curing adhesive and connecting guide sleeve to form a multi-core fiber "fan-in fan-out device".

[0052] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A multi-core fiber coupling method, characterized in that: a multi-core fiber (1) is taken, and HF acid etching solution is used to gradually etch each multi-core fiber core (102) from the end face of the multi-core fiber (1) to form a plurality of multi-core fiber core etching holes (101); an auxiliary etching sleeve (4) is included, the auxiliary etching sleeve (4) is provided with a sleeve joint part (402) which is slidably sleeved with the outer wall of the multi-core fiber (1), the auxiliary etching sleeve (4) is provided with a plurality of auxiliary etching capillaries (401) which are distributed in the same way as the multi-core fiber cores (102), each auxiliary etching capillary (401) is aligned with each multi-core fiber core (102), the connecting body of the multi-core fiber (1) and the auxiliary etching sleeve (4) is erected, and the auxiliary etching sleeve (4) is located at the upper end; HF acid etching solution is added into each auxiliary etching capillary (401) to etch the multi-core fiber core (102), the auxiliary etching capillary (401) moves downward as the etching depth increases, and the HF acid etching solution is poured out when the etching depth reaches the set depth; a single-mode fiber (2) is taken, and HF acid etching solution is used to etch the cladding of the single-mode fiber (2) from the outside to the outside wall of the single-mode fiber core (202) to form a plurality of single-mode fiber bare cores (201); each single-mode fiber bare core (201) is inserted into each multi-core fiber core etching hole (101), and the end face of the single-mode fiber bare core (201) is butted with the end face of the multi-core fiber core (102) at the bottom end of the multi-core fiber core etching hole (101); solidified glue is filled into the multi-core fiber core etching hole (101), and the solidified glue is completely solidified.

2. The method of claim 1, wherein: an etching liquid container (5) is included, the etching liquid container (5) is provided with HF acid etching solution; a sealing glue layer (203) is coated on the end of the single-mode fiber bare core (201), the single-mode fiber (2) is inserted into the etching liquid container (5) to a set depth, and when the cladding of the etching liquid container (5) is etched by the HF acid etching solution to the outside wall of the single-mode fiber bare core (201), the single-mode fiber (2) is pulled out.

3. The method of claim 1, wherein: a connecting guide sleeve (3) is included, the connecting guide sleeve (3) is provided with a sink (307), the sink (307) is provided with a plurality of single-mode fiber insertion holes (306) which are distributed in the same way as the multi-core fiber cores (102), and the single-mode fiber insertion holes (306) are through structures; the end of the multi-core fiber (1) is sleeved in the sink (307), each single-mode fiber (2) is inserted into the single-mode fiber insertion hole (306), and each single-mode fiber bare core (201) is inserted into each multi-core fiber core etching hole (101).

4. The method of claim 3, wherein: The sidewall of each single-mode fiber jack (306) is provided with a jack blind groove (304) in communication with a sink groove (307), the bottom end of the sink groove (307) is further provided with a glue inlet groove (302) and a glue guide branch groove (303) in communication with the glue inlet groove (302), the glue inlet groove (302) and the glue guide branch groove (303) are in communication with the single-mode fiber jack (306), the outer wall of the connecting guide sleeve (3) is provided with a glue inlet hole (301) and a glue overflow hole (305), the two ends of the glue inlet hole (301) and the glue overflow hole (305) are respectively in communication with the two ends of the glue inlet groove (302); a plug is installed in the glue overflow hole (305), the connecting guide sleeve (3) is injected with curing glue through the glue inlet hole (301), the curing glue fills the gap between the single-mode fiber core (202) and the multicore fiber core (102), the gap between the bottom end of the sink groove (307) and the end face of the multicore fiber (1), and the jack blind groove (304), until the plug in the glue overflow hole (305) is pushed out, and the glue injection is stopped.

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