Multi-core optical fiber fan-in and fan-out method and structure

Abstract

The invention discloses a multi-core optical fiber fan-in and fan-out method and a multi-core optical fiber fan-out structure, and belongs to the field of optical communication. Through the steps of array tail fiber preparation, multi-core tail fiber preparation, structure forming and single-mode optical fiber and multi-core optical fiber coupling, a single-mode optical fiber array tail fiber is adopted to replace a traditional single-fiber tail fiber, so that integration and miniaturization of a device are realized; therefore, the structural design and the processing technology are simplified; the cladding diameter of each single-mode optical fiber is corroded to be the same as the fiber core spacing of the multi-core optical fiber, emergent light beams of the single-mode optical fibers are matched with emergent light beams of the multi-core optical fiber in the aspects of cross angles and light spot sizes, coupling loss between the optical fibers is effectively reduced, meanwhile, crosstalk between different optical fiber channels can be reduced through the spatially separated layout, and the coupling loss between the optical fibers is reduced. And the performance of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of optical communication, and in particular to a multi-core optical fiber fan-in and fan-out method and structure. Background Art

[0002] Multi-core fiber (MCF) is a special fiber that contains multiple independent fiber cores. These cores can be used as signal transmission channels, so they have the advantages of high transmission capacity and high integration. They are widely used in data centers and high-speed communication networks. However, due to its unique structure and size, multi-core fiber cannot be directly fused with standard single-mode fiber (SMF), so it is necessary to use a multi-core fiber fan-in fan-out (FIFO) device. FIFO devices can achieve low-loss coupling between a single multi-core fiber and multiple single-core fibers.

[0003] At present, there are four methods for preparing FIFO devices: melt taper method, fiber bundle method, direct writing waveguide method and spatial optical lens coupling method. However, all four methods have defects: the melt taper method requires strict control of the heating taper process and has high process requirements; the fiber bundle method has a relatively complex operation process and requires high-precision operating equipment; the direct writing waveguide method has a long processing time, and the required laser equipment is expensive and the cost is high; the spatial optical lens coupling method has a complex operation and a high cost. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a multi-core optical fiber fan-in and fan-out method with simple process and low cost.

[0005] In order to overcome the deficiencies of the prior art, a second object of the present invention is to provide a multi-core optical fiber fan-in and fan-out structure with simple process and low cost.

[0006] One of the purposes of the present invention is achieved by the following technical solution:

[0007] A multi-core optical fiber fan-in and fan-out method comprises the following steps:

[0008] Preparation of array pigtails: corroding the cladding diameter of each single-mode optical fiber to the same as the core spacing of the multi-core optical fiber, inserting multiple single-mode optical fibers into a multi-hole capillary or a large-hole capillary capable of accommodating multiple single-mode optical fibers and fixing them to form an array pigtail, and processing the end of the array pigtail to form an inclination angle on the end face;

[0009] Preparing a multi-core pigtail: inserting a multi-core optical fiber into a single-hole capillary or a large-hole capillary capable of accommodating multiple single-mode optical fibers and fixing the multi-core pigtail to form a multi-core pigtail, processing the end of the multi-core pigtail to form an inclination angle on the end face, wherein the inclination angle of the multi-core pigtail is equal to the inclination angle of the array pigtail;

[0010] Structural forming: the array fiber pigtail and the first focusing lens are fixed by a bridge tube, the multi-core fiber pigtail and the second focusing lens are fixed by a bridge tube, and the array fiber pigtail and the multi-core fiber pigtail are encapsulated by an external sealing tube. At this time, the structure is the array fiber pigtail, the first focusing lens, the second focusing lens and the multi-core fiber pigtail in sequence, and the curvature radius and length of the first focusing lens and the second focusing lens are equal;

[0011] Coupling of single-mode optical fiber and multi-core optical fiber: the output beam angle of the single-mode optical fiber of the array fiber pigtail after passing through the first focusing lens is θ, and the beam waist radius is ω. The output beam angle of the multi-core fiber pigtail after passing through the second focusing lens is also θ, and the beam waist radius is also ω. Therefore, multiple single-mode optical fibers can be coupled to the multi-core optical fiber.

[0012] Furthermore, in the structure forming step, the first focusing lens and the second focusing lens are lenses with one side being a plane and the other side being a spherical surface, the end close to the array fiber pigtail is a slope, and the end of the first focusing lens away from the array fiber pigtail is a spherical surface; the end of the second focusing lens close to the multi-core fiber pigtail is a slope, and the end of the second focusing lens away from the multi-core fiber pigtail is a spherical surface.

[0013] Furthermore, in the structure forming step, the first focusing lens and the second focusing lens are lenses with spherical surfaces on both sides.

[0014] Furthermore, in the structure forming step, the first focusing lens and the second focusing lens are gradient refractive index self-focusing lenses.

[0015] Furthermore, the inclination angle of the multi-core pigtail and the inclination angle of the array pigtail are both 6-12 degrees.

[0016] Furthermore, in the step of preparing the array pigtail, the processing of the end of the array pigtail includes polishing and grinding.

[0017] Furthermore, in the step of preparing the multi-core pigtail, the processing of the end of the multi-core pigtail includes polishing and grinding.

[0018] The second object of the present invention is achieved by adopting the following technical solution:

[0019] A multi-core optical fiber fan-in and fan-out structure is manufactured according to any one of the above-mentioned multi-core optical fiber fan-in and fan-out methods, the multi-core optical fiber fan-in and fan-out structure comprises an array fiber pigtail, a first focusing lens, a bridge tube, a second focusing lens, a multi-core fiber pigtail and an outer sealing tube, the array fiber pigtail comprises a plurality of single-mode optical fibers and a multi-hole capillary or a large-hole capillary capable of accommodating a plurality of single-mode optical fibers, a plurality of the single-mode optical fibers are fixed to the multi-hole capillary or the large-hole capillary capable of accommodating a plurality of single-mode optical fibers, the array fiber pigtail is fixed to the first focusing lens through the bridge tube, the multi-core fiber pigtail comprises a multi-core optical fiber and a single-hole capillary, the multi-core optical fiber is fixed to the single-hole capillary, the multi-core fiber pigtail is fixed to the second focusing lens through the bridge tube, the outer sealing tube fixes the array fiber pigtail and the multi-core fiber pigtail, the cladding diameter of the single-mode optical fiber is the same as the core spacing of the multi-core optical fiber, the array fiber pigtail, the first focusing lens, the second focusing lens and the multi-core fiber pigtail are located on the same straight line, and the outer sealing tube is coaxially arranged with the straight line.

[0020] Furthermore, the end of the array pigtail toward the multi-core pigtail is inclined, and the end of the multi-core pigtail toward the array pigtail is inclined.

[0021] Compared with the prior art, the multi-core optical fiber fan-in and fan-out method of the present invention adopts single-mode optical fiber array pigtails to replace traditional single-fiber pigtails through the steps of preparing array pigtails, preparing multi-core pigtails, structural molding, and coupling single-mode optical fibers with multi-core optical fibers, thereby realizing the integration and miniaturization of the device, thereby simplifying the structural design and processing technology; the cladding diameter of each single-mode optical fiber is corroded to be the same as the core spacing of the multi-core optical fiber, the output light beam of the single-mode optical fiber is matched with the output light beam of the multi-core optical fiber in terms of the crossing angle and the spot size, effectively reducing the coupling loss between each optical fiber, and at the same time, the spatially separated layout helps to reduce the crosstalk between different optical fiber channels and improve the performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the multi-core optical fiber fan-in and fan-out method of the present invention;

[0023] Figure 2 A schematic diagram of a multi-core optical fiber fan-in and fan-out structure of the present invention;

[0024] Figure 3 for Figure 2 A schematic diagram of the structure of the array pigtail of the multi-core optical fiber fan-in and fan-out structure;

[0025] Figure 4 for Figure 2 A schematic diagram of the structure of a multi-core pigtail of a multi-core optical fiber fan-in and fan-out structure;

[0026] Figure 5 for Figure 2Coupling diagram of the multi-core fiber fan-in and fan-out structure.

[0027] In the figure: 10, array pigtail; 11, multi-hole capillary; 12, single-mode optical fiber; 20, first focusing lens; 30, bridge tube; 40, second focusing lens; 50, multi-core pigtail; 51, single-hole capillary; 52, multi-core optical fiber; 60, outer sealing tube. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be another intermediate component through which it is fixed. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be another intermediate component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be another intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0031] See also Figure 1 as well as Figure 2 The multi-core optical fiber fan-in and fan-out method of the present invention comprises the following steps:

[0032] Prepare the array pigtail 10: corrode the cladding diameter of each single-mode optical fiber 12 to be the same as the core spacing of the multi-core optical fiber 52, insert multiple single-mode optical fibers 12 into a multi-hole capillary 11 or a large-hole capillary that can accommodate multiple single-mode optical fibers 12 and fix them to form an array pigtail 10, and process the end of the array pigtail 10 so that the end face forms an inclination angle;

[0033] Prepare a multi-core pigtail 50: insert a multi-core optical fiber 52 into a single-hole capillary 51 or a large-hole capillary that can accommodate multiple single-mode optical fibers 12 and fix it to form a multi-core pigtail 50, and process the end of the multi-core pigtail 50 so that the end face forms an inclination angle, and the inclination angle of the multi-core pigtail 50 is equal to the inclination angle of the array pigtail 10;

[0034] Structural forming: the array fiber pigtail 10 and the first focusing lens 20 are fixed by a bridge tube 30, the multi-core fiber pigtail 50 and the second focusing lens 40 are fixed by a bridge tube 30, and the array fiber pigtail 10 and the multi-core fiber pigtail 50 are encapsulated by an outer sealing tube 60. At this time, the structure is the array fiber pigtail 10, the first focusing lens 20, the second focusing lens 40 and the multi-core fiber pigtail 50 in sequence, and the curvature radius and length of the first focusing lens 20 and the second focusing lens 40 are equal;

[0035] The single-mode optical fiber 12 is coupled with the multi-core optical fiber 52: the output beam angle of the single-mode optical fiber 12 of the array fiber pigtail 10 after passing through the first focusing lens 20 is θ, and the beam waist radius is ω. The output beam angle of the multi-core fiber pigtail 50 after passing through the second focusing lens 40 is also θ, and the beam waist radius is also ω. Therefore, multiple single-mode optical fibers 12 can be coupled with the multi-core optical fiber 52.

[0036] Specifically, in the step of preparing the array pigtail 10, the number of single-mode optical fibers 12 corresponds to the multi-core optical fiber 52. The purpose of corroding the cladding diameter of each single-mode optical fiber 12 to the same core spacing as the multi-core optical fiber 52 is to enable the output beam of the single-mode optical fiber 12 to match the output beam of the multi-core optical fiber 52 in terms of the cross angle and the spot size, thereby reducing the coupling loss between each optical fiber. At the same time, the spatially separated layout helps to reduce the crosstalk between different optical fiber channels, improves the performance of the system, and has a high practical value. In this embodiment, the diameter of the single-mode optical fiber 12 is corroded to 42um, and the core spacing of the multi-core optical fiber 52 is also 42um. The number of single-mode optical fibers 12 is 4, and the multi-core optical fiber 52 corresponds to 4-core optical fibers. The number of holes on the multi-hole capillary 11 is also 4. The single-mode optical fiber 12 is fixed to the multi-hole capillary 11 by glue. The processing of the end of the array pigtail 10 includes polishing and grinding, so that the end face forms an inclination angle of 6-12 degrees to increase the return loss of the device. Preferably, the end surface inclination angle is 8°.

[0037] Specifically, in the step of preparing the multi-core pigtail 50, the multi-core optical fiber 52 is fixed to the single-hole capillary 51 by glue. The single-hole capillary 51 is made of glass and has only one mounting hole. The end of the multi-core pigtail 50 is processed including polishing and grinding to form an inclination angle at the end face. The inclination angle of the multi-core pigtail 50 is equal to the inclination angle of the array pigtail 10, which is an inclination angle of 6-12 degrees. Preferably, the end face inclination angle is 8°.

[0038] Specifically, in the structural molding step, the bridge tube 30 is cylindrical and made of glass. The end of the first focusing lens 20 close to the array pigtail 10 is a bevel, and the end of the first focusing lens 20 away from the array pigtail 10 is a spherical surface; the end of the second focusing lens 40 close to the multi-core pigtail 50 is a bevel, and the end of the second focusing lens 40 away from the multi-core pigtail 50 is a spherical surface. The inclination angle of the bevel of the first focusing lens 20 is the same as the inclination angle of the bevel of the second focusing lens 40. The inclination angle of the bevel of the first focusing lens 20 is the same as the inclination angle of the multi-core pigtail 50. In other embodiments, both ends of the first focusing lens 20 are spherical or gradient refractive index self-focusing lenses. Both ends of the second focusing lens 40 are spherical or gradient refractive index self-focusing lenses.

[0039] In this embodiment, the inclination angle of the bevel of the first focusing lens 20, the inclination angle of the bevel of the second focusing lens 40, the inclination angle of the multi-core pigtail 50, and the inclination angle of the array pigtail 10 are all 6-12 degrees. Preferably, the inclination angle is 8°, and the 8-degree bevel can meet the general needs of optical communication and can be adjusted to other angles according to actual use. The outer sealing tube 60 is made of glass, and the outer sealing tube 60 and the bridge tube 30 are fixed by glue, so that the array pigtail 10, the first focusing lens 20, the second focusing lens 40 and the multi-core pigtail 50 are located on the same straight line, and the outer sealing tube 60 is coaxially arranged with the straight line.

[0040] Please continue reading Figures 2 to 5 The present application also discloses a multi-core optical fiber fan-in and fan-out structure, which is manufactured according to the multi-core optical fiber fan-in and fan-out method.

[0041] The fan-in and fan-out structure of the multi-core optical fiber 52 includes an array pigtail 10 , a first focusing lens 20 , a bridge tube 30 , a second focusing lens 40 , a multi-core pigtail 50 and an outer sealing tube 60 .

[0042] The array pigtail 10 includes a plurality of single-mode optical fibers 12 and a porous capillary 11, and the plurality of single-mode optical fibers 12 are fixed to the porous capillary 11. Specifically, the plurality of single-mode optical fibers 12 are inserted into the holes of the porous capillary 11 and fixed by glue. The number of holes of the porous capillary 11 is the same as the number of single-mode optical fibers 12. The cladding diameter of the single-mode optical fiber 12 is the same as the core spacing of the multi-core optical fiber 52. The core spacing of the array pigtail 10 is made consistent with the core spacing of the multi-core pigtail 50. When the radius of curvature and the length of the first focusing lens 20 and the second focusing lens 40 are equal, the output beam of the single-mode optical fiber can match the output beam of the four-core optical fiber in terms of the cross angle and the spot size. This structural design effectively reduces the coupling loss between each optical fiber. At the same time, the spatially separated layout helps to reduce the crosstalk between different optical fiber channels, improves the performance of the system, and has a high practical value. The processing of the end of the array pigtail 10 includes polishing and grinding, so that the end face forms an inclination angle of 6-12 degrees to increase the return loss of the device. Preferably, the end face inclination angle is 8 degrees.

[0043] The first focusing lens 20 has an inclined surface at one end close to the array pigtail 10 and a spherical surface at one end away from the array pigtail 10. The inclined surface of the first focusing lens 20 has the same inclination angle as the end of the array pigtail 10.

[0044] The bridge tube 30 is a glass tube, and the array fiber pigtail 10 is fixed to the first focusing lens 20 through the bridge tube 30. Specifically, the array fiber pigtail 10 is partially sleeved inside the bridge tube 30 and fixed to the bridge tube 30 by glue, and the first focusing lens 20 is partially sleeved inside the bridge tube 30 and fixed to the bridge tube 30 by glue. The array fiber pigtail 10 and the first focusing lens 20 are located on the same straight line, and the bridge tube 30 is coaxially arranged with the array fiber pigtail 10 and the first focusing lens 20.

[0045] The end of the second focusing lens 40 close to the multi-core pigtail 50 is an inclined surface, and the end of the second focusing lens 40 away from the multi-core pigtail 50 is a spherical surface. The inclination angle of the inclined surface of the second focusing lens 40 is equal to the inclination angle of the end surface of the multi-core pigtail 50. The first focusing lens 20 and the second focusing lens 40 have the same curvature radius and length.

[0046] The multi-core pigtail 50 includes a multi-core optical fiber 52 and a single-hole capillary 51. The single-hole capillary 51 is provided with a through hole, and the multi-core optical fiber 52 is passed through the through hole and fixed to the single-hole capillary 51 by glue. The end of the multi-core pigtail 50 is processed by polishing and grinding, so that the end face forms an inclination angle of 6-12 degrees to increase the return loss of the device. Preferably, the end face inclination angle is 8°.

[0047] The multi-core pigtail 50 is fixed to the second focusing lens 40 by a bridge tube 30. Specifically, the multi-core pigtail 50 is partially sleeved inside the bridge tube 30 and fixed to the bridge tube 30 by glue, and the second focusing lens 40 is partially sleeved inside the bridge tube 30 and fixed to the bridge tube 30 by glue. The multi-core pigtail 50 and the second focusing lens 40 are located on the same straight line, and the bridge tube 30 is coaxially arranged with the multi-core pigtail 50 and the second focusing lens 40.

[0048] The outer sealing tube 60 is made of glass and is fixed to the bridge tube 30 by glue, so that the array pigtail 10, the first focusing lens 20, the second focusing lens 40 and the multi-core pigtail 50 are located on the same straight line, and the outer sealing tube 60 is coaxially arranged with the straight line.

[0049] The output beam angle of the array fiber pigtail 10 after passing through the first focusing lens 20 is θ, and the beam waist radius is ω. In order to enable the output beam of the array fiber pigtail 10 to couple with the multi-core fiber pigtail 50, it is necessary to ensure that the output beam angle of the multi-core fiber pigtail 50 after passing through the second focusing lens 40 is also θ, and the beam waist radius is also ω. Since the single-mode optical fiber 12 is subjected to corrosion treatment, the core distance of the array fiber pigtail 10 is consistent with the core distance of the multi-core fiber pigtail 50. Therefore, the same focusing lens is used for both, which can ensure that the output beam angle and the beam waist radius are equal, so that the Gaussian beam coupling efficiency emitted by the single-mode optical fiber 12 and the multi-core fiber pigtail 50 is higher.

[0050] Compared with the prior art, the fan-in and fan-out method of the multi-core optical fiber 52 of the present invention adopts the single-mode optical fiber 12 array optical fiber 10 to replace the traditional single-fiber optical fiber through the steps of preparing the array optical fiber 10, preparing the multi-core optical fiber 50, structural molding and coupling the single-mode optical fiber 12 with the multi-core optical fiber 52, so as to realize the integration and miniaturization of the device, thereby simplifying the structural design and processing technology; the cladding diameter of each single-mode optical fiber 12 is corroded to be the same as the core spacing of the multi-core optical fiber 52, and the output light beam of the single-mode optical fiber 12 is matched with the output light beam of the multi-core optical fiber 52 in terms of the crossing angle and the spot size, which effectively reduces the coupling loss between each optical fiber. At the same time, the spatially separated layout helps to reduce the crosstalk between different optical fiber channels and improve the performance of the system.

[0051] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which are equivalent modifications and improvements made to the above embodiments based on the essential technology of the present invention, and all of them belong to the protection scope of the present invention.

Claims

1. A multi-core optical fiber fan-in and fan-out method, characterized in that: The following steps are involved: Preparation of array pigtails: corroding the cladding diameter of each single-mode optical fiber to the same as the core spacing of the multi-core optical fiber, inserting multiple single-mode optical fibers into a multi-hole capillary or a large-hole capillary capable of accommodating multiple single-mode optical fibers and fixing them to form an array pigtail, and processing the end of the array pigtail to form an inclination angle on the end face; Preparing a multi-core pigtail: inserting a multi-core optical fiber into a single-hole capillary or a large-hole capillary capable of accommodating multiple single-mode optical fibers and fixing the multi-core pigtail to form a multi-core pigtail, processing the end of the multi-core pigtail to form an inclination angle on the end face, wherein the inclination angle of the multi-core pigtail is equal to the inclination angle of the array pigtail; Structural forming: the array fiber pigtail and the first focusing lens are fixed by a bridge tube, the multi-core fiber pigtail and the second focusing lens are fixed by a bridge tube, and the array fiber pigtail and the multi-core fiber pigtail are encapsulated by an external sealing tube. At this time, the structure is the array fiber pigtail, the first focusing lens, the second focusing lens and the multi-core fiber pigtail in sequence, and the curvature radius and length of the first focusing lens and the second focusing lens are equal; Coupling of single-mode optical fiber and multi-core optical fiber: the output beam angle of the single-mode optical fiber of the array fiber pigtail after passing through the first focusing lens is θ, and the beam waist radius is ω. The output beam angle of the multi-core fiber pigtail after passing through the second focusing lens is also θ, and the beam waist radius is also ω. Therefore, multiple single-mode optical fibers can be coupled to the multi-core optical fiber.

2. The multi-core optical fiber fan-in and fan-out method according to claim 1, characterized in that: In the structure forming step, the first focusing lens and the second focusing lens are lenses with one side being a plane and the other side being a spherical surface, the end close to the array fiber pigtail is an inclined surface, and the end of the first focusing lens away from the array fiber pigtail is a spherical surface; the end of the second focusing lens close to the multi-core fiber pigtail is an inclined surface, and the end of the second focusing lens away from the multi-core fiber pigtail is a spherical surface.

3. The multi-core optical fiber fan-in and fan-out method according to claim 1, characterized in that: In the structure forming step, the first focusing lens and the second focusing lens are lenses with spherical surfaces on both sides.

4. The multi-core optical fiber fan-in and fan-out method according to claim 1, characterized in that: In the structure forming step, the first focusing lens and the second focusing lens are gradient refractive index self-focusing lenses.

5. The multi-core optical fiber fan-in and fan-out method according to claim 1, characterized in that: The inclination angle of the multi-core pigtail and the inclination angle of the array pigtail are both 6-12 degrees.

6. The multi-core optical fiber fan-in and fan-out method according to claim 1, characterized in that: In the step of preparing the array pigtail, processing the end of the array pigtail includes polishing and grinding.

7. The multi-core optical fiber fan-in and fan-out method according to claim 1, characterized in that: In the step of preparing the multi-core pigtail, processing the end of the multi-core pigtail includes polishing and grinding.

8. A multi-core optical fiber fan-in and fan-out structure, manufactured according to the multi-core optical fiber fan-in and fan-out method according to any one of claims 1 to 7, characterized in that: The multi-core fiber fan-in and fan-out structure includes an array fiber pigtail, a first focusing lens, a bridge tube, a second focusing lens, a multi-core fiber pigtail and an outer sealing tube. The array fiber pigtail includes multiple single-mode optical fibers and a multi-hole capillary or a large-hole capillary that can accommodate multiple single-mode optical fibers. Multiple single-mode optical fibers are fixed to the multi-hole capillary or the large-hole capillary that can accommodate multiple single-mode optical fibers. The array fiber pigtail is fixed to the first focusing lens through the bridge tube. The multi-core fiber pigtail includes a multi-core optical fiber and a single-hole capillary. The multi-core optical fiber is fixed to the single-hole capillary. The multi-core fiber pigtail is fixed to the second focusing lens through the bridge tube. The outer sealing tube fixes the array fiber pigtail and the multi-core fiber pigtail. The cladding diameter of the single-mode optical fiber is the same as the core spacing of the multi-core optical fiber. The array fiber pigtail, the first focusing lens, the second focusing lens and the multi-core fiber pigtail are located on the same straight line, and the outer sealing tube is coaxially arranged with the straight line.

9. The multi-core optical fiber fan-in and fan-out structure according to claim 8, characterized in that: The end of the array pigtail facing the multi-core pigtail is at an inclination angle, and the end of the multi-core pigtail facing the array pigtail is at an inclination angle.

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