Multi-core optical fiber fan-in and fan-out device and processing method thereof

Abstract

The invention relates to the technical field of optical communication, in particular to a multi-core optical fiber fan-in and fan-out device and a processing method thereof. The multi-core optical fiber fan-in and fan-out device comprises a multi-core optical fiber insertion core piece, a multi-core optical fiber, a plurality of single-core optical fibers and a plurality of three-dimensional miniature optical path elements. A plurality of optical fiber channels are arranged in the multi-core optical fiber insertion core part, the multi-core optical fiber and the single-core optical fibers are inserted into the optical fiber channels respectively, and the end faces of one ends of the multi-core optical fiber and the single-core optical fibers extend out of the optical fiber channels; each fiber core of the multi-core optical fiber is connected with the fiber core of each single-core optical fiber through the three-dimensional micro optical path element, and optical interconnection between the fiber core of the multi-core optical fiber and the fiber core of the single-core optical fiber is realized through the three-dimensional micro optical path element, so that a fan-in and fan-out function is realized; the three-dimensional micro optical path element is directly processed on the end face of each fiber core in a two-photon polymerization processing mode. According to the fan-in and fan-out device provided by the invention, the loss of each channel is uniform, secondary coupling alignment is not needed, the processing difficulty is low, and the efficiency is high.

Description

Technical Field

[0001] The present application relates to the field of optical communication technology, and more specifically, to a multi-core optical fiber fan-in and fan-out device and a processing method thereof. Background Art

[0002] At present, the mainstream multi-core fiber fan-in and fan-out devices are mainly based on methods such as fiber fusion taper and femtosecond laser modification of glass materials.

[0003] The fiber fusion taper method arranges multiple optical fibers in a specific ratio, then fuses them at high temperature and simultaneously stretches them in both directions. As the fiber bundle is stretched, it becomes increasingly thinner in the middle, until the diameter of the bundle, which is several hundred microns, is reduced to 125 microns. The reduced diameter bundle is then cut in half, and the tapered end face now has the same diameter and core arrangement as a multi-core fiber. Finally, the multi-core fiber and the tapered surface of the fused and stretched optical bundle are coupled and docked, accurately linking each linear element together, thus completing the fan-in and fan-out process from multi-core fiber to single-core fiber. This method can achieve low loss, but to achieve this, a long transition region must be retained during the fiber fusion taper. This long section of the fiber bundle is used to reduce the diameter from several hundred microns to 125 microns. This results in devices produced using the fiber fusion taper method often being very long, making them difficult to integrate. Furthermore, after the taper is completed, the fiber bundle must be coupled and docked with the cross-section of the multi-core fiber. This step, to ensure low loss, requires extremely high coupling alignment accuracy, further increasing the difficulty and cost of fabrication.

[0004] Using femtosecond lasers to modify glass materials to create multi-core fiber fan-in and fan-out devices is a cutting-edge technology that has emerged in recent years. Its core is to use ultrafast lasers to induce refractive index changes within the glass, directly "carving" out three-dimensional optical waveguides. This method uses a high numerical aperture objective lens to focus the femtosecond laser beam inside the glass material. Transparent materials such as sapphire and quartz usually do not absorb lasers in the corresponding wavelength band, but near the focus of the femtosecond laser, a power of more than 10 TW / cm can be obtained. 2The high energy intensity causes thermal effects and nonlinear effects in the glass material. The laser is absorbed only near the focus, which causes the modification of the glass material at the focal position, resulting in a change in the refractive index. By controlling the trajectory of the femtosecond laser focus, a three-dimensional waveguide structure can be realized, and a multi-core fiber fan-in and fan-out structure can be realized. Finally, the multi-core fiber and the single-core fiber array are coupled and aligned on both sides of the three-dimensional waveguide to obtain a multi-core fiber fan-in and fan-out device. This method can achieve lower transmission loss, but still requires high-precision secondary coupling alignment to reduce the end-face coupling loss. In addition, the refractive index change achieved by femtosecond laser modification of glass materials is small, usually on the order of 0.001, which leads to a large bending radius of the three-dimensional waveguide. The total length of the three-dimensional waveguide finally processed is large and cannot be integrated. At the same time, after the three-dimensional waveguide structure inside the glass material is processed, high-precision secondary coupling alignment is required on both sides. The overall process is relatively cumbersome and the cost is difficult to reduce. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art that require secondary coupling alignment, which makes processing difficult, and to provide a multi-core optical fiber fan-in and fan-out device and a processing method thereof, which does not require secondary coupling alignment, reduces processing difficulty, and improves device integration.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: A multi-core fiber fan-in and fan-out device is provided, comprising a multi-core fiber optic ferrule, a multi-core optical fiber, multiple single-core optical fibers, and multiple three-dimensional micro-optical path elements; multiple optical fiber channels are provided inside the multi-core fiber ferrule, the multi-core optical fiber and multiple single-core optical fibers are respectively inserted into each of the optical fiber channels, and one end face of the multi-core optical fiber and the single-core optical fiber extends out of the optical fiber channel; each core of the multi-core optical fiber is connected to the core of each single-core optical fiber through the three-dimensional micro-optical path element, and optical interconnection between the multi-core optical fiber core and the single-core optical fiber core is achieved through the three-dimensional micro-optical path element, thereby realizing the fan-in and fan-out functions; the three-dimensional micro-optical path element is directly processed on the end face of each core by two-photon polymerization processing.

[0007] The present invention provides a multi-core fiber fan-in and fan-out device, which fixes the multi-core fiber and single-core fiber to be connected in a fiber channel through a multi-core fiber optic ferrule, and then uses a two-photon polymerization processing method to directly process a three-dimensional micro-optical path element on the end face of the fiber core to be connected. The three-dimensional micro-optical path element obtained by direct polymerization processing can realize optical interconnection between the multi-core fiber core and the single-core fiber core, thereby realizing the fan-in and fan-out functions; the multi-core fiber and single-core fiber of the present invention are both fixed in the channel of the multi-core fiber optic ferrule, and this arrangement facilitates the subsequent processing of the three-dimensional micro-optical path element; the three-dimensional micro-optical path element is directly processed on the end face of each fiber core by a two-photon polymerization processing method, without the need for secondary coupling and alignment, with low processing difficulty and high efficiency, and can meet most of the needs of multi-core fiber fan-in and fan-out devices.

[0008] In the present invention, the multi-core optical fiber ferrule is a solid three-dimensional structure formed by curing a photosensitive resin, and has a plurality of tiny optical fiber channels with gradually varying diameters in the solid structure.

[0009] Furthermore, one end of the multi-core fiber optic plug is the channel exit end, and the other end is the channel entrance end; the diameter of the optical fiber channel gradually decreases from the channel entrance end to the channel exit end. The multi-core optical fiber and the single-core optical fiber are inserted into the optical fiber channel from the channel entrance end. Before insertion, the multi-core optical fiber and the single-core optical fiber need to strip off the first protective shell to expose the fiber core. However, since the exposed fiber core is relatively fragile, it is necessary to insert it to the unstripped part during insertion so that a section of the first protective shell is inserted into the optical fiber channel together, so that there is no exposed optical fiber on the side of the channel entrance end; and for the optical fiber exit end, since it is necessary to directly process three-dimensional micro-optical path elements on the end faces of each fiber core, the distance between each fiber core is as small as possible; therefore, the diameter of the optical fiber channel gradually decreases from the channel entrance end to the channel exit end.

[0010] Furthermore, the channel exits of the multiple fiber channels are arranged at the channel exit end according to a predetermined rule, and the through-entrances of the multiple fiber channels are arranged at the channel entrance end according to the same rule as the channel exits; the spacing between the channel entrances of the multiple fiber channels is greater than the spacing between the channel exits. This arrangement prevents the individual optical fibers from interlacing within the multi-core fiber ferrule, making it easier for operators to observe the arrangement of the fiber core end faces and obtain the spatial distribution of the individual fiber cores, thereby facilitating the subsequent two-photon polymerization processing of three-dimensional micro-optical circuit components.

[0011] Furthermore, the optical fiber channel includes a multi-core channel and multiple single-core channels; the diameter value of the channel outlet end of the multi-core optical fiber ferrule is the same as the diameter value of the optical fiber that needs to be fanned in and fanned out; that is, the diameter value of the multi-core channel is the same as the diameter value of the single-core channel.

[0012] Furthermore, the exit and entrance of the optical fiber channel are arranged in the same manner, ensuring that the spacing between the cores of each multi-core optical fiber that needs to be connected and pass light is consistent with the core of the single-core optical fiber, and the spacing is minimized as much as possible. At the same time, the diameter of the multi-core channel exit is consistent with the diameter of the optical fiber that needs to fan in and fan out. Typically, in order to meet the above requirements, the multiple optical fiber channels are arranged according to a centrally symmetrical rule, with the multi-core channel located in the center and the single-core channels arranged at equal intervals around the optical fiber channel.

[0013] Furthermore, at the channel entrance end of the multi-core optical fiber ferrule, the arrangement of the optical fiber channel entrances is the same as that of the channel exits, and is also arranged in a centrally symmetrical manner; the spacing between the channel entrances is greater than the spacing between the channel exits, and the diameter of each channel entrance is significantly increased compared to the channel exit, usually greater than 1 mm.

[0014] Furthermore, for each of the fiber channels, within a set length range from the channel exit, each of the fiber channels is parallel to each other and has the same diameter. Within a 4-5mm range near the channel exit end of the multi-core fiber ferrule, it is necessary to ensure that the arrangement of the fiber channels is completely consistent with the arrangement of the exit, and that each fiber channel is parallel to each other and has the same diameter. This is to ensure that when the optical fibers are finally emitted from the exit, they are parallel to each other and do not cross each other. The same diameter is to facilitate the subsequent processing and connection of three-dimensional micro-optical circuit components.

[0015] Furthermore, the three-dimensional micro-optical element comprises a cylindrical spatial waveguide and at least two reflectors positioned on the cylindrical spatial waveguide. The two reflectors cooperate to achieve a 180-degree turn of the light beam, enabling the light beam to be transmitted from one core of a multi-core optical fiber to the core of a single-core optical fiber, thus achieving interconnected light transmission. By processing the three-dimensional micro-optical element between all the multi-core optical fiber cores and single-core optical fibers that need to be interconnected, a complete fan-in and fan-out structure is achieved. In the present invention, a two-photon polymerization method is used to polymerize the photoresist to obtain the desired three-dimensional micro-optical element.

[0016] Furthermore, the device further comprises a first protective housing, which is disposed externally of the multi-core fiber optic ferrule. The first protective housing is provided with a groove at the outlet end of the channel, and the outlet end of the multi-core fiber optic ferrule is located within the groove. The first protective housing is intended to protect the internal multi-core fiber optic ferrule from external damage and to provide both installation and fixation. It also serves as a fixture during fiber end face polishing, two-photon polymerization processing of three-dimensional micro-optical paths, and the like. The first protective housing is typically manufactured by machining metal materials.

[0017] Furthermore, at the outlet end of the channel, the multi-core optical fiber and each of the single-core optical fibers are fixed on the multi-core optical fiber ferrule by dripping glue.

[0018] The present invention also provides a method for processing the multi-core optical fiber fan-in and fan-out device described above, comprising the following steps: S1. Fabrication of a multi-core fiber optic ferrule: Using 3D printing technology, photosensitive resin materials are processed to produce a multi-core fiber optic ferrule. S2. Strip the outer sleeve and protective layer of one end of the multi-core optical fiber and the single-core optical fiber to expose the core within a set length range; then sequentially insert the multi-core optical fiber and the single-core optical fiber into each optical fiber channel from the channel entrance end of the multi-core optical fiber ferrule, and allow the multi-core optical fiber and the single-core optical fiber to pass through the channel outlet end; S3. Add glue to the channel outlet and cure it. Fix the optical fibers exiting each fiber channel to the multi-core fiber ferrule outlet. Ensure that the cured glue thickness and hardness are within the set range. S4. Polishing the fiber end faces of the multi-core fiber and single-core fiber at the outlet of the channel; S5. Secure the multi-core optical fiber ferrule processed in step S4 below the objective lens of a two-photon polymerization processing device. Adjust the two-photon polymerization processing device so that the processing field of view covers the positions of each optical fiber end face. Observe the arrangement of the optical fiber cores at the optical fiber end face by reflection microscopy to obtain the spatial distribution of each optical core. Then, through two-photon polymerization processing, polymerize and print a three-dimensional micro-optical path element between the optical cores to be connected. S6. Performing a development operation on the three-dimensional micro-optical circuit element obtained in step S5 to remove excess unpolymerized photoresist, thereby completing a multi-core fiber fan-in and fan-out device; wherein the obtained three-dimensional micro-optical circuit element can realize optical interconnection between the multi-core fiber core and the single-core fiber core, thereby realizing fan-in and fan-out functions.

[0019] The present invention provides a processing method for a multi-core optical fiber fan-in and fan-out device. The entire preparation process does not require the use of high-precision active alignment and coupling technology. After the optical fiber is manually fixed in the multi-core optical fiber ferrule, it only needs to be placed in a two-photon polymerization processing device. The processing can be completed through the in-situ detection technology provided by the device. The device is processed and formed in sequence without the need for secondary alignment and coupling, and the operation process is simple.

[0020] Furthermore, in step S2, it further includes dripping glue on the fiber entrance end of the multi-core optical fiber ferrule and curing it to fix the multi-core optical fiber and the single-core optical fiber on the fiber entrance end of the multi-core optical fiber ferrule; After step S1 and before step S4, the method further includes using a first protective shell to cover the multi-core optical fiber ferrule.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. A multi-core fiber fan-in and fan-out device of the present invention secures the multi-core fiber and single-core fiber to be connected in a fiber channel via a multi-core fiber ferrule. Then, a three-dimensional micro-optical path element is directly fabricated on the end faces of the fiber cores to be connected using two-photon polymerization. The three-dimensional micro-optical path element obtained by direct polymerization can achieve optical interconnection between the multi-core fiber cores and the single-core fiber cores, thereby realizing fan-in and fan-out functions. The three-dimensional micro-optical path element is directly fabricated on the end faces of each fiber core using two-photon polymerization, eliminating the need for secondary coupling and alignment, resulting in low processing difficulty and high efficiency. The fan-in and fan-out device of the present invention has uniform loss across each channel, meeting most requirements of multi-core fiber fan-in and fan-out devices.

[0022] 2. The present invention provides a method for processing a multi-core fiber fan-in and fan-out device. The entire preparation process does not require the use of high-precision active alignment and coupling technology. After the optical fiber is manually fixed in the multi-core fiber ferrule, it only needs to be placed in the two-photon polymerization processing equipment. The processing can be completed through the in-situ detection technology provided by the equipment. The components are processed and formed in sequence without the need for secondary alignment and coupling, and the operation process is simple.

[0023] 3. The multi-core fiber fan-in and fan-out device of the present invention benefits from the structural design of the multi-core fiber ferrule. The multi-core fiber and multiple single-core fibers are arranged in a centrally symmetrical structure. Typically, the multi-core fiber is fixed in the center, and the other multiple single-core fibers are arranged in a circle with equal spacing around the multi-core fiber. Thanks to this centrally symmetrical arrangement, the spacing between each pair of single-core fiber cores to be connected and the corresponding cores of the multi-core fiber is equal. The three-dimensional micro-optical path structure to be processed is also exactly the same, with only differences in angle and position. This minimizes loss differences introduced by structural differences and ensures uniformity across the channels of the resulting fan-in and fan-out device.

[0024] 4. The present invention provides a method for processing a multi-core fiber fan-in and fan-out device. Through the structural design of the multi-core fiber ferrule, the end faces of all optical fibers are vertically exposed directly below the objective lens of the two-photon processing equipment. Within the imaging field of view, all fiber cores are clearly visible, and the accurate position of the fiber core can be obtained through simple image recognition feature processing. There is no need to introduce additional complex three-dimensional positioning technology, and the detection capability requirements of the two-photon polymerization processing equipment are relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the multi-core optical fiber ferrule and the first protective shell in Example 1; Figure 2Schematic diagram of connecting the multi-core optical fiber core and the single-core optical fiber core through a three-dimensional micro optical path element in Example 1; Figure 3 Schematic diagram of the structure of the three-dimensional micro optical path element in Example 1; Figure 4 Schematic diagram of the structure of the multi-core optical fiber ferrule in Example 1; Figure 5 Schematic diagram of the four-core fan-in and fan-out device prepared in Example 2.

[0026] In the accompanying drawings: 1. Multi-core optical fiber ferrule; 11. Optical fiber channel; 12. Channel entrance; 13. Channel exit; 2. Multi-core optical fiber; 3. Single-core optical fiber; 4. Three-dimensional micro-optical path element; 41. Cylindrical space waveguide; 42. Reflector; 5. First protective shell; 51. Groove; 6. Second protective shell. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and are schematic, not actual, representations. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced in size, and do not represent the actual dimensions of the products. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted from the drawings.

[0028] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0029] Example 1 This embodiment is the first embodiment of a multi-core optical fiber fan-in and fan-out device. Figures 1 to 4As shown, it includes a multi-core fiber optic ferrule 1, a multi-core optical fiber 2, multiple single-core optical fibers 3, and multiple three-dimensional micro-optical path elements 4; a plurality of optical fiber channels 11 are provided inside the multi-core fiber optic ferrule 1, the multi-core optical fiber 2 and the multiple single-core optical fibers 3 are respectively inserted in each optical fiber channel 11, and one end face of the multi-core optical fiber 2 and the single-core optical fiber 3 extends out of the optical fiber channel 11; each core of the multi-core optical fiber 2 is connected to the core of each single-core optical fiber 3 through the three-dimensional micro-optical path element 4, and the optical interconnection between the core of the multi-core optical fiber 2 and the core of the single-core optical fiber 3 is realized through the three-dimensional micro-optical path element 4, thereby realizing the fan-in and fan-out functions; the three-dimensional micro-optical path element 4 is directly processed on the end face of each core by two-photon polymerization processing.

[0030] In the present invention, Figure 1 and Figure 4 As shown, the multi-core fiber ferrule 1 is a solid, three-dimensional structure formed by curing a photosensitive resin. Within this solid structure are multiple tiny, tapered fiber channels 11. The multi-core fiber ferrule 1 is used to secure the multi-core optical fiber 2 and single-core optical fiber 3 bundles to be connected, aligning the fiber end faces according to specific requirements, facilitating the identification of individual fiber cores and the fabrication of the three-dimensional micro-optical circuit element 4. The multi-core optical fiber 2 ferrule is typically made of photosensitive resin and manufactured using 3D printing technology.

[0031] like Figure 1 and Figure 4 As shown, one end of the multi-core fiber optic ferrule 1 is the channel exit end, and the other end is the channel entrance end; the diameter of the optical fiber channel 11 gradually decreases from the channel entrance end to the channel exit end. The multi-core optical fiber 2 and the single-core optical fiber 3 are inserted into the optical fiber channel 11 from the channel entrance end. Before insertion, the multi-core optical fiber 2 and the single-core optical fiber 3 need to strip the first protective shell 5 to expose the fiber core. However, since the exposed fiber core is relatively fragile, it is necessary to insert it to the unstripped part during insertion so that a section of the first protective shell 5 is inserted into the optical fiber channel 11 together, so that there is no exposed optical fiber on the side of the channel entrance end; and for the optical fiber exit end, since the three-dimensional micro-optical path element 4 needs to be directly processed on the end face of each fiber core, the distance between each fiber core is as small as possible; therefore, the diameter of the optical fiber channel 11 gradually decreases from the channel entrance end to the channel exit end.

[0032] like Figure 1 and Figure 4As shown, the channel exits 13 of the multiple optical fiber channels 11 are arranged at the channel exit end according to a predetermined rule, and the through-entrances of the multiple optical fiber channels 11 are arranged at the channel entrance end according to the same rule as the channel exits 13. The spacing between the channel entrances 12 of the multiple optical fiber channels 11 is greater than the spacing between the channel exits 13. This arrangement prevents the individual optical fibers from interlacing within the multi-core optical ferrule 1, making it easier for operators to observe the arrangement of the fiber core end faces and obtain the spatial distribution of the individual fiber cores, thereby facilitating the subsequent two-photon polymerization processing of the three-dimensional micro-optical circuit element 4.

[0033] In this embodiment, the optical fiber channel 11 includes a multi-core channel and multiple single-core channels; the diameter value of the channel outlet end of the multi-core optical fiber ferrule 1 is the same as the diameter value of the optical fiber that needs to be fanned in and fanned out; that is, the diameter value of the multi-core channel is the same as the diameter value of the single-core channel.

[0034] In this embodiment, the exits and entrances of the optical fiber channels 11 are arranged in the same manner, ensuring that the spacing between the cores of each multi-core optical fiber 2 and the cores of each single-core optical fiber 3 that needs to be connected and pass light is consistent, and the spacing is minimized. At the same time, the diameter of the multi-core channel exit 13 is consistent with the diameter of the optical fiber that needs to be fanned in and out. Typically, to meet the above requirements, multiple optical fiber channels 11 are arranged according to a centrally symmetrical rule, with the multi-core channel located in the center and the single-core channels arranged at equal intervals around the optical fiber channel 11.

[0035] In this embodiment, at the channel entrance end of the multi-core optical fiber ferrule 1, the arrangement of the entrances of each optical fiber channel 11 is the same as the arrangement of the channel exits 13, and is also arranged in a centrally symmetrical manner; the spacing between the channel entrances 12 is greater than the spacing between the channel exits 13, and the diameter of each channel entrance 12 is significantly increased compared to the channel exit 13, usually greater than 1 mm.

[0036] like Figure 1 As shown, for each fiber channel 11, within a set length range from the channel exit, each fiber channel 11 is parallel to each other, and the diameters of each fiber channel within this range are also the same. Within a 4-5mm range on the inner side of the multi-core fiber ferrule near the channel exit, it is necessary to ensure that the arrangement of each fiber channel 11 is completely consistent with the arrangement of the exit and that each fiber channel 11 is parallel to each other. This is to ensure that when the optical fibers are finally emitted from the exit, they are parallel to each other and do not cross each other.

[0037] like Figure 2 and Figure 3As shown, the three-dimensional micro optical path element 4 and at least two reflectors 42 located on the cylindrical space waveguide 41 cooperate with each other to achieve a 180° turn of the light beam, thereby transmitting the light beam from one core of the multi-core optical fiber 2 to the core of the single-core optical fiber 3, thereby achieving interconnected light transmission. Figure 2 and Figure 3 As shown, the two fiber cores to be connected are parallel to each other, and a reflector 42 is machined in the axial extension direction of each fiber core at an angle of 45° to the core axis, so that the light can be turned back 90°. The two reflectors 42 cooperate with each other to achieve a 180° turn of the light beam. This embodiment realizes a complete fan-in and fan-out structure by machining the above-mentioned three-dimensional micro-optical path element 4 between the cores of all multi-core optical fibers 2 and single-core optical fibers 3 that need to be interconnected. In the present invention, a two-photon polymerization method is used to polymerize the photoresist to obtain the required three-dimensional micro-optical path element 4.

[0038] It should be noted that the three-dimensional micro-optical path element provided above is one of the implementation methods. The three-dimensional micro-optical path element 4 can also be other combinations of three-dimensional waveguides, reflectors, lenses, parabolic mirrors, etc., as long as it can achieve optical interconnection and 180-degree return of the light beam.

[0039] In this embodiment, to facilitate subsequent two-photon polymerization processing, the multi-core optical fiber 2 and each single-core optical fiber 3 are fixed to the multi-core optical fiber ferrule 1 at the channel outlet by dripping glue and curing it. After curing, the glue has a high hardness and can be polished to ensure that the polishing of the optical fiber end face can be carried out smoothly. It should be noted that in this embodiment, before performing two-photon polymerization processing on the three-dimensional micro-optical path element 4, it is necessary to first polish the end face of the fiber core located at the channel outlet.

[0040] The present embodiment provides a multi-core fiber fan-in and fan-out device, which fixes the multi-core optical fiber 2 and the single-core optical fiber 3 to be connected in the optical fiber channel 11 through the multi-core optical fiber ferrule 1, and then directly processes the three-dimensional micro-optical path element 4 on the end face of the core to be connected by two-photon polymerization processing. The three-dimensional micro-optical path element 4 obtained by direct polymerization processing can realize the optical interconnection between the core of the multi-core optical fiber 2 and the core of the single-core optical fiber 3, thereby realizing the fan-in and fan-out functions; the multi-core optical fiber 2 and the single-core optical fiber 3 of the present invention are both fixed in the channel of the multi-core optical fiber ferrule 1. This arrangement facilitates the subsequent processing of each core end face, without the need for secondary coupling and alignment, with low processing difficulty and high efficiency, and can meet most of the needs of multi-core fiber fan-in and fan-out devices.

[0041] This embodiment provides a multi-core fiber fan-in and fan-out device, in which, thanks to the structural design of the multi-core fiber ferrule 1 of this embodiment, the multi-core fiber 2 and the multiple single-core fibers 3 are arranged in a centrally symmetrical structure. Usually, the multi-core fiber 2 is fixed in the middle position, and the other multiple single-core fibers 3 are arranged in a circle with equal spacing around the multi-core fiber 2. In this way, the spacing between the cores of each pair of single-core fibers 3 to be connected and the corresponding cores of the multi-core fibers 2 is equal, and the three-dimensional micro-optical path elements 4 to be processed are also exactly the same, with only differences in angle and position. This avoids the loss differences introduced by structural differences as much as possible and ensures the uniformity of each channel of the final fan-in and fan-out device.

[0042] The present embodiment provides a multi-core fiber fan-in and fan-out device. Thanks to the structural design of the multi-core fiber ferrule 1 provided in this embodiment, the end faces of all optical fibers are vertically exposed directly below the objective lens of the two-photon polymerization processing equipment. Within the imaging field of view, all fiber cores are clearly visible, and the accurate position of the fiber core can be obtained through simple image recognition feature processing. When using the two-photon polymerization processing method to prepare the three-dimensional micro-optical path element 4, there is no need to use high-precision active alignment coupling technology. After manually fixing the optical fiber to the multi-core fiber ferrule 2, it only needs to be placed in the two-photon polymerization processing equipment. The processing can be completed through the in-situ detection technology provided by the equipment. The processing is sequentially processed and formed without the need for secondary alignment coupling, and the operation process is simple.

[0043] This embodiment provides a multi-core fiber fan-in and fan-out device with a small device size and high integration. The processing accuracy of the two-photon polymerization processing technology is very high, usually reaching the 100nm level, which can achieve very precise three-dimensional structure processing. At the same time, the three-dimensional micro-optical path element 4 is obtained by curing the photoresist, and the external environment is air. The two have a large refractive index difference. Combined with the 90-degree deflection transmission of the light beam by the micro-reflector, the light beam transmission between the fiber cores can be realized in a very small structure. The size of the general three-dimensional micro-optical path is in the range of 100-300μm, which has great potential for large-scale integrated applications.

[0044] Example 2 This embodiment is a second embodiment of a multi-core optical fiber fan-in and fan-out device. This embodiment is similar to the first embodiment, except that Figure 1 As shown, the multi-core optical fiber ferrule 1 further includes a first protective housing 5, which is sleeved over the multi-core optical fiber ferrule 1. The first protective housing 5 is provided with a groove 51 at the channel outlet end, and the outlet end of the multi-core optical fiber ferrule 1 is located within the groove 51. The first protective housing 5 is intended to protect the internal multi-core optical fiber ferrule 1 from external damage and to provide both installation and fixation. It also serves as a fixing fixture during fiber end face grinding, two-photon polymerization processing of three-dimensional micro-optical paths, and other processes. The first protective housing 5 is typically manufactured by machining metal materials.

[0045] like Figure 1 As shown, the interior of the first protective shell 5 is provided with a cavity for accommodating the multi-core optical fiber ferrule 1, one end of which is the insertion end of the cavity, and the other end is provided with a groove 51 connected to the cavity; the multi-core optical fiber ferrule 1 is inserted into the cavity from the insertion end until the channel outlet end of the multi-core optical fiber ferrule 1 is located in the groove 51, and does not protrude outside the groove 51, which plays a protective role without affecting subsequent processing. Adding glue to the groove 51 to solidify the fiber core can fix the fiber core and prevent the glue from flowing out. Moreover, the groove 51 is designed to ensure that the glue can be better dripped to ensure uniform thickness at each position. After the glue is solidified, it is also convenient for the subsequent grinding of the optical fiber end face; the three-dimensional micro optical path element 4 finally obtained by two-photon polymerization processing is also located in the groove 51, which can play a certain protective role.

[0046] In this embodiment, if Figure 5 As shown, a second protective shell 6 is also provided. The second protective shell 6 is a metal shell. The second protective shell 6 is wrapped around the outside of the first protective shell 5, and the entire fan-in and fan-out device is wrapped in the second protective shell 6. An opening is only provided at the entrance end of the channel for the optical fiber to pass through.

[0047] Example 3 This embodiment is a second embodiment of a method for processing a multi-core optical fiber fan-in and fan-out device, which is used to process the multi-core optical fiber fan-in and fan-out device of the first or second embodiment, and includes the following steps: Step S1. Preparing a multi-core optical fiber ferrule 1: Using 3D printing technology, photosensitive resin material is processed to prepare a multi-core optical fiber ferrule 1.

[0048] 3D printing technology includes but is not limited to Digital Light Processing (DLP) technology. DLP is a high-precision additive manufacturing technology based on photocuring. It dynamically projects ultraviolet light patterns through a digital micromirror device (DMD) to cure photosensitive resin layer by layer.

[0049] Step S2. Strip the outer sleeve and protective layer from one end of the multi-core optical fiber 2 and the single-core optical fiber 3 to expose the fiber core within a set length range; then insert the multi-core optical fiber 2 and the single-core optical fiber 3 into each optical fiber channel 11 from the channel entrance end of the multi-core optical fiber ferrule 1, and make the multi-core optical fiber 2 and the single-core optical fiber 3 pass through the channel exit end.

[0050] During the insertion process, insert the outer fiber sleeve into the channel entrance 12 of the multi-core fiber ferrule 1 to ensure that no unprotected bare fiber is exposed to the outside world. This is to protect the fiber, which is very fragile and easily bends. By doing this, the bare fiber is protected inside the multi-core fiber ferrule 2, and the final device has better stability.

[0051] In addition, ultraviolet glue is dripped on one side of the channel entrance 12 of the multi-core optical fiber ferrule 1 and cured to fix the optical fiber and the multi-core optical fiber ferrule 1 together.

[0052] Step S3. Add glue to the channel outlet and solidify it. Fix the optical fibers passing through each optical fiber channel 11 to the channel outlet of the multi-core optical fiber ferrule 1. Ensure that the thickness and hardness of the glue after curing are within the set range.

[0053] Typically, this thickness is in the range of 1-2mm. The glue used should have a high hardness after curing, including but not limited to casting glue and epoxy resin glue. This is to ensure smooth polishing of the subsequent fiber end face.

[0054] Step S4. Polish the fiber end faces of the multi-core optical fiber 2 and the single-core optical fiber 3 at the channel outlet.

[0055] Use standard fiber polishing processes to ensure that each fiber end face on the outlet side has a very good surface finish. Since the optical fiber and the cured glue at the outlet end of the multi-core fiber ferrule 1 channel will be masked during the polishing process, to ensure the masking effect, it is necessary to use a glue with a higher hardness after curing in the previous step.

[0056] Step S5. Fix the multi-core optical fiber insert 1 processed in step S4 under the objective lens of the two-photon polymerization processing equipment, adjust the two-photon polymerization processing equipment so that the processing field of view covers the position of each optical fiber end face, observe the arrangement of the optical fiber end face cores through reflective microscopy, and obtain the spatial position distribution of each fiber core; through two-photon polymerization processing, polymerize and print the three-dimensional micro optical path element 4 between the various fiber cores that need to be connected.

[0057] In this step, the channel outlet end of the polished multi-core optical fiber ferrule 1 is fixed directly below the objective lens of the two-photon polymerization processing equipment, and the two-photon polymerization processing equipment is adjusted so that the processing field of view just covers the position of each optical fiber end face. At this time, the various optical fibers and their cores to be connected are directly exposed below the objective lens of the two-photon polymerization processing equipment. The arrangement of the optical fiber end faces and the cores can be observed through reflective microscopy to obtain the spatial position distribution of each core. Compared with the detection method of photon leads, this method has low detection difficulty and high detection accuracy.

[0058] By using two-photon polymerization processing technology, a specific three-dimensional micro optical path element 4 is polymerized and printed between the various fiber cores that need to be connected, so that light can pass through the various fiber cores that need to be connected.

[0059] Step S6. The three-dimensional micro-optical circuit element 4 obtained in step S5 is developed to remove excess unpolymerized photoresist, thereby completing the multi-core fiber fan-in and fan-out device; wherein the obtained three-dimensional micro-optical circuit element 4 can realize optical interconnection between the core of the multi-core optical fiber 2 and the core of the single-core optical fiber 3, thereby realizing the fan-in and fan-out functions.

[0060] In this embodiment, in order to facilitate the grinding of the optical fiber end face and the subsequent two-photon polymerization processing, before step S4, a first protective shell 5 can be put on the outside of the multi-core optical fiber ferrule 1. The first protective shell 5 has a certain hardness, which is convenient for clamping and fixing the multi-core optical fiber ferrule 1.

[0061] In addition, after step S6, a second protective shell 6 is put on to protect the entire multi-core optical fiber ferrule and the processed three-dimensional microstructure to avoid external environmental pollution.

[0062] The present embodiment provides a method for processing a multi-core fiber fan-in and fan-out device, which has the advantages of one-time molding, no need for secondary alignment, high processing efficiency, low difficulty in in-situ detection and identification, high detection accuracy, small structural size, high integration, and simple processing process. It can meet most of the needs of multi-core fiber fan-in and fan-out devices.

[0063] like Figure 5 As shown, a four-core fiber fan-in and fan-out device is provided, which is used to connect the four cores of a four-core fiber to four single-core fibers 3 respectively, so as to realize signal transmission between each core of the four-core fiber and a single-core fiber 3.

[0064] like Figure 5 As shown, the left side shows the final product of the four-core fiber fan-in and fan-out device, and the right side shows the four-core fiber ferrule, ferrule protective housing, high-hardness glue, and three-dimensional micro-optical element 4. Installing a second protective housing 6 outside the ferrule protective housing completes the complete packaging of the entire device.

[0065] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A multi-core optical fiber fan-in and fan-out device, characterized in that: The invention comprises a multi-core optical fiber insert (1), a multi-core optical fiber (2), a plurality of single-core optical fibers (3), and a plurality of three-dimensional micro-optical path elements (4); a plurality of optical fiber channels (11) are provided inside the multi-core optical fiber insert (1), the multi-core optical fiber (2) and the plurality of single-core optical fibers (3) are respectively inserted into each of the optical fiber channels (11), and one end face of each of the multi-core optical fiber (2) and the single-core optical fiber (3) extends out of the optical fiber channel (11); each core of the multi-core optical fiber (2) is connected to the core of each of the single-core optical fibers (3) through the three-dimensional micro-optical path element (4), and optical interconnection between the core of the multi-core optical fiber (2) and the core of the single-core optical fiber (3) is achieved through the three-dimensional micro-optical path element (4), thereby realizing fan-in and fan-out functions; the three-dimensional micro-optical path element (4) is directly processed on the end face of each core by two-photon polymerization processing.

2. The multi-core optical fiber fan-in and fan-out device according to claim 1, characterized in that: One end of the multi-core optical fiber ferrule (1) is a channel outlet end, and the other end is a channel inlet end; the diameter of the optical fiber channel (11) gradually decreases from the channel inlet end to the channel outlet end.

3. The multi-core optical fiber fan-in and fan-out device according to claim 2, characterized in that: The channel outlets (13) of the plurality of optical fiber channels (11) are arranged at the channel outlet end according to a set rule, and the through entrances of the plurality of optical fiber channels (11) are arranged at the channel entrance end according to the same rule as the channel outlets (13); and the spacing value between the channel entrances (12) of the plurality of optical fiber channels (11) is greater than the spacing value between the channel outlets (13).

4. The multi-core optical fiber fan-in and fan-out device according to claim 3, characterized in that: The optical fiber channel (11) includes a multi-core channel and a plurality of single-core channels; the plurality of optical fiber channels (11) are arranged according to a centrally symmetrical rule, with the multi-core channel located in the center and the single-core channels arranged at equal intervals around the optical fiber channel (11).

5. The multi-core optical fiber fan-in and fan-out device according to claim 3, characterized in that: For each of the optical fiber channels (11), within a set length range from the channel outlet end, each of the optical fiber channels (11) is parallel to each other.

6. The multi-core optical fiber fan-in and fan-out device according to any one of claims 2 to 5, characterized in that: The three-dimensional micro optical path element (4) comprises a cylindrical space waveguide and at least two reflectors located on the cylindrical space waveguide. The two reflectors cooperate with each other to achieve a 180-degree turn of the light beam, thereby achieving transmission of the light beam from one core of the multi-core optical fiber (2) to the core of the single-core optical fiber (3), thereby achieving interconnected light transmission.

7. The multi-core optical fiber fan-in and fan-out device according to any one of claims 2 to 5, characterized in that: The invention also comprises a first protective shell (5), wherein the first protective shell (5) is sleeved on the outside of the multi-core optical fiber ferrule (1), and the first protective shell (5) is provided with a groove (51) at the outlet end of the channel, and the outlet end of the channel of the multi-core optical fiber ferrule (1) is located in the groove (51).

8. The multi-core optical fiber fan-in and fan-out device according to claim 6, characterized in that: At the outlet end of the channel, the multi-core optical fiber (2) and each of the single-core optical fibers (3) are fixed on the multi-core optical fiber insert (1) by dripping glue.

9. A method for processing a multi-core optical fiber fan-in and fan-out device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Preparation of a multi-core optical fiber ferrule (1): Processing a photosensitive resin material using 3D printing technology to prepare a multi-core optical fiber ferrule (1); S2. peeling off the outer sleeve and protective layer of one end of the multi-core optical fiber (2) and the single-core optical fiber (3) to expose the fiber core within a set length range; then inserting the multi-core optical fiber (2) and the single-core optical fiber (3) into each optical fiber channel (11) from the channel entrance end of the multi-core optical fiber ferrule (1) in sequence, and passing the multi-core optical fiber (2) and the single-core optical fiber (3) out from the channel exit end; S3. Add glue to the outlet of the channel and solidify it, and fix the optical fibers passing through each optical fiber channel (11) to the outlet of the channel of the multi-core optical fiber ferrule (1); And ensure that the thickness of the glue after curing is within the set range, and the hardness of the glue after curing is within the set range; S4. Polishing the fiber end faces of the multi-core optical fiber (2) and the single-core optical fiber (3) at the outlet end of the channel; S5. Fixing the multi-core optical fiber ferrule (1) processed in step S4 below the objective lens of the two-photon polymerization processing device, adjusting the two-photon polymerization processing device, and obtaining the spatial position distribution of each fiber core; polymerizing and printing a three-dimensional micro optical path element (4) between each fiber core to be connected by two-photon polymerization processing; S6. The three-dimensional micro-optical path element (4) obtained in step S5 is subjected to a development operation to remove the excess unpolymerized photoresist, thereby completing the multi-core optical fiber fan-in and fan-out device; wherein the obtained three-dimensional micro-optical path element (4) can realize optical interconnection between the core of the multi-core optical fiber (2) and the core of the single-core optical fiber (3), thereby realizing the fan-in and fan-out functions.

10. The method for processing a multi-core optical fiber fan-in and fan-out device according to claim 9, wherein: In step S2, it also includes dripping glue on the optical fiber entrance end of the multi-core optical fiber ferrule (1) and curing it, and fixing the multi-core optical fiber (2) and the single-core optical fiber (3) on the optical fiber entrance end of the multi-core optical fiber ferrule (1); After step S1 and before step S4, the method further includes using a first protective shell (5) to be sleeved on the multi-core optical fiber ferrule component (1).

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