A multi-core fiber fan-in fan-out device and a processing method thereof

Abstract

The application relates to the technical field of optical communication, and relates to a multi-core fiber fan-in fan-out device and a processing method thereof. The multi-core fiber fan-in fan-out device comprises a multi-core fiber ferrule, a multi-core fiber, a plurality of single-core fibers and a plurality of three-dimensional micro optical path elements. The multi-core fiber ferrule is internally provided with a plurality of fiber channels, the multi-core fiber and the plurality of single-core fibers are respectively inserted into the fiber channels, and the end faces of the multi-core fiber and the single-core fibers all extend out of the fiber channels. The fiber cores of the multi-core fiber are respectively connected with the fiber cores of the single-core fibers through the three-dimensional micro optical path elements, the optical interconnection between the fiber cores of the multi-core fiber and the fiber cores of the single-core fibers is realized through the three-dimensional micro optical path elements, so that the fan-in fan-out function is realized. The three-dimensional micro optical path elements are directly processed on the end faces of the fiber cores through a two-photon polymerization processing mode. The fan-in fan-out device provided by the application is uniform in channel loss, does not need secondary coupling alignment, is low in processing difficulty and high in efficiency.

Description

TECHNICAL FIELD

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

[0002] At present, the mainstream multi-core fiber fan-in fan-out device is mainly based on fiber fusion tapering, femtosecond laser modification of glass material, etc.

[0003] The fiber fusion tapering method arranges multiple optical fibers together according to a specific ratio, then melts at high temperature, and simultaneously stretches to both sides. When stretching, the middle of the fiber bundle becomes thinner and thinner, until the diameter of the fiber bundle of several hundred um is reduced to 125 um, and then the waist of the fiber bundle with reduced diameter is cut off. At this time, the diameter of the tapered end face and the fiber core arrangement are consistent with the multi-core fiber. Finally, the multi-core fiber and the tapered surface of the fiber bundle after fusion stretching are coupled and connected, so that each linearly accurate link is connected together, which completes the fan-in fan-out from the multi-core fiber to the single-core fiber. This method can achieve relatively low loss, but in order to obtain low loss, a relatively long transition area needs to be reserved when the fiber is fused and tapered, and the diameter of the fiber bundle is reduced from several hundred microns to 125 microns through a long fiber bundle, which results in that the device obtained by the fiber fusion tapering method usually has a relatively long length and cannot be integrated. At the same time, after the tapering is completed, the fiber bundle needs to be coupled and connected with the cross section of the multi-core fiber. In order to ensure low loss, very high coupling alignment accuracy is required, which further increases the difficulty and cost of processing and preparation.

[0004] The use of femtosecond laser modification of glass material to prepare multi-core fiber fan-in fan-out device is a cutting-edge technology that has emerged in recent years. Its core is to induce refractive index changes in glass by ultrafast laser, and directly "carve" three-dimensional optical waveguide. This method focuses the femtosecond laser beam inside the glass material through a high numerical aperture objective lens. Transparent materials such as sapphire and quartz will not absorb the corresponding waveband of laser, but a refractive index change greater than 10 TW / cm 2The high energy intensity of the femtosecond laser causes thermal effect, nonlinear effect and the like of the glass material, only the focus position absorbs the laser, thereby causing modification of the glass material at the focus position, and causing change of the refractive index. By controlling the femtosecond laser focus track, the three-dimensional waveguide structure can be realized, and the fan-in fan-out structure of the multi-core fiber 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, and the multi-core fiber fan-in fan-out device can be obtained. This method can realize low transmission loss, but high-precision secondary coupling and alignment are still required to reduce the end surface coupling loss. In addition, the refractive index change realized by the femtosecond laser modification of the glass material is small, usually in the order of 0.001, which leads to a large bending radius of the three-dimensional waveguide, and the total length of the three-dimensional waveguide processed finally is large, which cannot be integrated. At the same time, after the three-dimensional waveguide structure in the glass material is processed, high-precision secondary coupling and alignment are required on both sides, and the overall process is complicated, and the cost is difficult to reduce. SUMMARY

[0005] The purpose of the present application is to overcome the deficiency of the prior art that requires secondary coupling and alignment, and to provide a multi-core fiber fan-in fan-out device and a processing method thereof, which do not require secondary coupling and alignment, reduce the processing difficulty, and improve the device integration.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a multi-core fiber fan-in fan-out device, which comprises a multi-core fiber ferrule, a multi-core fiber, a plurality of single-core fibers, and a plurality of three-dimensional micro optical path elements. The multi-core fiber ferrule is internally provided with a plurality of optical fiber channels, the multi-core fiber and the plurality of single-core fibers are respectively inserted into each optical fiber channel, and the end faces of one end of the multi-core fiber and the single-core fibers all extend out of the optical fiber channel. Each core of the multi-core fiber is connected to the core of each single-core fiber through the three-dimensional micro optical path element, and the optical interconnection between the cores of the multi-core fiber and the cores of the single-core fiber is realized through the three-dimensional micro optical path element, thereby realizing the fan-in fan-out function. The three-dimensional micro optical path element is directly processed on the end face of each core by a two-photon polymerization processing method.

[0008] The application provides a multi-core fiber fan-in fan-out device, which is characterized in that: a multi-core fiber ferrule is used to fix the multi-core fiber and the single-core fiber to be connected in the fiber channel, then a three-dimensional micro optical path component is directly processed on the end face of the fiber core to be connected by using a two-photon polymerization processing mode, the three-dimensional micro optical path component directly obtained by the polymerization processing can realize the optical interconnection between the multi-core fiber and the single-core fiber, thereby realizing the fan-in fan-out function; the multi-core fiber and the single-core fiber are both fixed in the channel of the multi-core fiber ferrule, so that the subsequent processing of the three-dimensional micro optical path component is facilitated; the three-dimensional micro optical path component is directly processed on the end face of each fiber core by using the two-photon polymerization processing mode, without the need for secondary coupling alignment, so that the processing difficulty is low, the efficiency is high, and the vast majority of the needs of the multi-core fiber fan-in fan-out device can be met.

[0009] In the application, the multi-core fiber ferrule is a solid three-dimensional structure after the curing of a photosensitive resin, and a plurality of small fiber channels with gradually changing diameters are arranged in the solid structure.

[0010] Further, one end of the multi-core fiber ferrule is a channel outlet end, and the other end is a channel inlet end; the diameter value of the fiber channel gradually decreases from the channel inlet end to the channel outlet end. The multi-core fiber and the single-core fiber are inserted into the fiber channel from the channel inlet end, and before the insertion, the multi-core fiber and the single-core fiber both need to be stripped of the first protective shell to expose the fiber core. However, the exposed fiber core is relatively fragile, so when inserted, it needs to be inserted to the unstripped part, so that a section of the first protective shell is inserted into the fiber channel together, so that on one side of the channel inlet end, no exposed fiber is exposed to the outside. As for the fiber outlet end, since the three-dimensional micro optical path component needs to be directly processed on the end face of each fiber core, the spacing between each fiber core is as small as possible. Therefore, the diameter value of the fiber channel gradually decreases from the channel inlet end to the channel outlet end.

[0011] Further, the channel outlets of the plurality of fiber channels are arranged on the channel outlet end according to a set rule, and the channel inlets of the plurality of fiber channels are arranged on the channel inlet end according to the same rule as the channel outlets. The spacing value between each channel inlet of the plurality of fiber channels is greater than the spacing value between each channel outlet. In this way, the fibers can be prevented from crossing each other inside the multi-core fiber ferrule, and the arrangement of the fiber core end faces and the spatial position distribution of each fiber core can be observed by the operator, so as to facilitate the subsequent two-photon polymerization processing of the three-dimensional micro optical path component.

[0012] Further, the fiber channel includes a multi-core channel and a plurality of single-core channels; the diameter value of the channel outlet end of the multi-core fiber ferrule is the same as the diameter value of the fiber to be fan-in fan-out, that is, the diameter value of the multi-core channel is the same as the diameter value of the single-core channel.

[0013] Further, the arrangement of the exit and entrance of the fiber channel is the same, and the spacing between the core of the multi-core fiber and the core of the single-core fiber is consistent and as small as possible. Meanwhile, the diameter of the multi-core channel exit is consistent with the diameter of the fiber that needs to be fanned in and out. Generally, in order to meet the above requirements, a plurality of the fiber channels are arranged according to the rule of central symmetry, and the multi-core channel is located at the center, and each single-core channel is arranged at equal intervals around the fiber channel.

[0014] Further, at the entrance end of the multi-core fiber ferrule, the arrangement of each fiber channel entrance is the same as that of the channel exit, and is arranged in a central symmetric manner. The spacing between the channel entrances is greater than that between the channel exits, and the diameter of each channel entrance is significantly increased compared with that of the channel exit, generally greater than 1 mm.

[0015] Further, for each fiber channel, within a certain length range from the channel exit end, each fiber channel is parallel to each other and has the same diameter. Within a range of 4-5 mm near the channel exit end inside the multi-core fiber ferrule, it is necessary to ensure that the arrangement of each fiber channel is completely consistent with that of the exit, and each fiber channel is parallel to each other and has the same diameter. This is to ensure that the final fiber exits at the exit without crossing each other, and the same diameter is to facilitate the subsequent processing and connection of the three-dimensional micro optical path element.

[0016] Further, the three-dimensional micro optical path element includes a cylindrical space waveguide and at least two mirrors located on the cylindrical space waveguide. Through the cooperation of the two mirrors, 180° turning of the light beam is realized, the light beam is transmitted from one core of the multi-core fiber to the core of the single-core fiber, and the interconnection of the light is realized. By processing the above three-dimensional micro optical path element between all the multi-core fiber cores and single-core fibers that need to be interconnected, a complete fan-in and fan-out structure is realized. In the present application, a two-photon polymerization processing method is used to polymerize and process photoresist to obtain the required three-dimensional micro optical path element.

[0017] Further, it further includes a first protective shell, the first protective shell is sleeved outside the multi-core fiber ferrule, and the first protective shell is provided with a groove at the channel exit end, and the exit end of the multi-core fiber ferrule is located in the groove. The first protective shell is to protect the internal multi-core fiber ferrule from damage by the outside world, and also serves the functions of installation and fixation. It serves as a fixing clamp in the case of fiber end face grinding, two-photon polymerization processing of three-dimensional micro optical path, etc. The first protective shell is usually made of metal material by mechanical processing.

[0018] Further, at the channel outlet end, the multicore optical fiber and the single-core optical fiber are fixed on the multicore optical fiber ferrule by dropping glue.

[0019] The application also provides a processing method of the multicore optical fiber fan-in fan-out device, comprising the following steps:

[0020] S1. Preparing a multicore optical fiber ferrule: using 3D printing technology to process photosensitive resin material to obtain a multicore optical fiber ferrule;

[0021] S2. Stripping the outer sleeve and the protective layer of one end of the multicore optical fiber and the single-core optical fiber to expose the core in a set length range; then inserting the multicore optical fiber and the single-core optical fiber into the optical fiber channels of the multicore optical fiber ferrule from the channel inlet end of the optical fiber channel in sequence, and making the multicore optical fiber and the single-core optical fiber pass out from the channel outlet end;

[0022] S3. Dropping glue at the channel outlet end to solidify and fix the optical fiber passing out from each optical fiber channel at the channel outlet end of the multicore optical fiber ferrule; and ensuring that the thickness of the solidified glue is within a set range and the hardness of the solidified glue is within a set range;

[0023] S4. Polishing the end face of the multicore optical fiber and the single-core optical fiber at the channel outlet end;

[0024] S5. Fixing the multicore optical fiber ferrule processed in step S4 below the objective lens of a two-photon polymerization processing device, adjusting the two-photon polymerization processing device so that the processing field covers the position of each optical fiber end face, observing the core arrangement of the optical fiber end face by a reflective microscopic imaging method to obtain the spatial position distribution of each core; and polymerizing and printing a three-dimensional micro optical path element between each core to be connected by a two-photon polymerization processing method;

[0025] S6. Developing the three-dimensional micro optical path element obtained in step S5 to remove the excess photoresist that has not been polymerized, and completing the multicore optical fiber fan-in fan-out device; wherein the three-dimensional micro optical path element can realize optical interconnection between the multicore optical fiber core and the single-core optical fiber core, thereby realizing the fan-in fan-out function.

[0026] The processing method of the multicore optical fiber fan-in fan-out device of the application does not need to use high-precision active alignment coupling technology in the entire preparation process. After the optical fiber is manually fixed in the multicore optical fiber ferrule, it only needs to be placed into the two-photon polymerization processing device, and the in-situ detection technology of the device can complete the processing in sequence, without the need for secondary alignment coupling, and the operation process is simple.

[0027] Further, in step S2, further comprising dripping glue at the entrance end of the channel of the multi-core fiber ferrule to fix the multi-core fiber and the single-core fiber at the entrance end of the channel of the multi-core fiber ferrule.

[0028] After step S1 and before step S4, further comprising using a first protective shell to cover the multi-core fiber ferrule.

[0029] Compared with the prior art, the beneficial effects of the present application are:

[0030] 1. A multi-core fiber fan-in fan-out device of the present application, by fixing the multi-core fiber and the single-core fiber to be connected in the fiber channel through the multi-core fiber ferrule, and then directly processing the three-dimensional micro optical path components on the fiber core end face to be connected by using the two-photon polymerization processing method, the three-dimensional micro optical path components obtained by direct polymerization processing can realize the optical interconnection between the multi-core fiber core and the single-core fiber core, thereby realizing the fan-in fan-out function; the three-dimensional micro optical path components are directly processed on each fiber core end face by using the two-photon polymerization processing method, without the need for secondary coupling alignment, the processing difficulty is low, the efficiency is high, the fan-in fan-out device of the present application has uniform channel loss, and can meet most of the needs of the multi-core fiber fan-in fan-out device.

[0031] 2. A processing method of a multi-core fiber fan-in fan-out device of the present application, the entire preparation process does not need to use high-precision active alignment coupling technology, after the fiber is fixed in the multi-core fiber ferrule by manual operation, only needs to be placed into the two-photon polymerization processing equipment, the in-situ detection technology of the equipment can be used to complete the processing, and the processing is sequentially formed, without the need for secondary alignment coupling, and the operation process is simple.

[0032] 3. A multi-core fiber fan-in fan-out device of the present application, benefiting from the structural design of the multi-core fiber ferrule, the multi-core fiber and the plurality of single-core fibers are arranged in a central symmetric structure, usually the multi-core fiber is fixed at the middle position, and the plurality of single-core fibers are arranged at equal intervals around the multi-core fiber. Benefiting from this central symmetric arrangement, the spacing between each pair of single-core fiber cores to be connected and the corresponding multi-core fiber cores is equal, and the three-dimensional micro optical path structures to be processed are also completely the same, only the angle and position are different. This can as much as possible avoid the loss difference caused by structural difference, and ensure the uniformity of each channel of the finally obtained fan-in fan-out device.

[0033] 4. The processing method of the multi-core fiber fan-in fan-out device of the application, through the structural design of the multi-core fiber ferrule, the end faces of all the optical fibers are vertically exposed directly below the objective lens of the two-photon processing equipment, in the imaging field of view, all the cores are clearly visible, the accurate position of the core can be obtained through simple image recognition feature processing, without the need for additional introduction of complex three-dimensional positioning technology, the detection ability requirement of the two-photon polymerization processing equipment is lower. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The structure schematic diagram of the multi-core fiber ferrule and the first protective shell in the embodiment one;

[0035] Figure 2 The schematic diagram of the connection of the multi-core fiber core and the single-core fiber core through the three-dimensional micro optical path element in the embodiment one;

[0036] Figure 3 The structure schematic diagram of the three-dimensional micro optical path element in the embodiment one;

[0037] Figure 4 The structure schematic diagram of the multi-core fiber ferrule in the embodiment one;

[0038] Figure 5 The schematic diagram of the four-core fiber core fan-in fan-out device prepared in the embodiment two.

[0039] In the drawings: 1, multi-core fiber ferrule; 11, fiber channel; 12, channel entrance; 13, channel exit; 2, multi-core fiber; 3, single-core fiber; 4, three-dimensional micro optical path element; 41, cylindrical space waveguide; 42, mirror; 5, first protective shell; 51, groove; 6, second protective shell. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with the specific embodiments. Among them, the drawings are only used for example description, and the representation is only a schematic diagram, not a physical diagram, and cannot be understood as the limitation of the application; in order to better illustrate the embodiments of the application, some components of the drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it can be understood that some known structures and their descriptions in the drawings can be omitted.

[0041] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationships in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0042] Embodiment one

[0043] The present embodiment is a first embodiment of a multi-core fiber fan-in fan-out device, as shown in Figures 1 to 4 , comprising a multi-core fiber ferrule 1, a multi-core fiber 2, a plurality of single-core fibers 3, and a plurality of three-dimensional micro optical path elements 4; the multi-core fiber ferrule 1 is internally provided with a plurality of fiber channels 11, the multi-core fiber 2 and the plurality of single-core fibers 3 are respectively inserted into each fiber channel 11, and the end faces of the multi-core fiber 2 and the single-core fiber 3 extend out of the fiber channel 11; each core of the multi-core fiber 2 is connected to the core of each single-core fiber 3 through the three-dimensional micro optical path element 4, and the optical interconnection between the cores of the multi-core fiber 2 and the single-core fiber 3 is realized through the three-dimensional micro optical path element 4, thereby realizing the fan-in fan-out function; the three-dimensional micro optical path element 4 is directly processed on the end face of each core through a two-photon polymerization processing method.

[0044] In the present application, as shown in Figure 1 and Figure 4 , the multi-core fiber ferrule 1 is a solid three-dimensional structure after curing of a photosensitive resin, and has a plurality of small, diameter-gradually-changing fiber channels 11 in the solid structure. The multi-core fiber ferrule 1 is used to fix the bundle of multi-core fiber 2 and single-core fiber 3 that need to be connected, and to arrange the fiber end faces according to specific requirements, facilitating the identification of each core and the processing of the three-dimensional micro optical path element 4. The multi-core fiber 2 ferrule is usually made of photosensitive resin material and is processed by 3D printing technology.

[0045] As shown in Figure 1 and Figure 4As shown, one end of the multi-core fiber ferrule 1 is the channel exit end, and the other end is the channel entrance end; the diameter of the fiber channel 11 gradually decreases from the channel entrance end to the channel exit end. The multi-core fiber 2 and the single-core fiber 3 are inserted into the fiber channel 11 from the channel entrance end, and before insertion, the multi-core fiber 2 and the single-core fiber 3 both need to be stripped of the first protective shell 5 to expose the cores, but because the exposed cores are relatively fragile, when inserted, they need to be inserted to the unstripped part, so that a section of the first protective shell 5 is inserted into the fiber channel 11, so that on one side of the channel entrance end, there is no exposed fiber exposed to the outside; and for the fiber exit end, because it is necessary to directly process three-dimensional micro optical path elements 4 on each core end face, the spacing between each core is as small as possible; therefore, the diameter of the fiber channel 11 gradually decreases from the channel entrance end to the channel exit end.

[0046] As shown in Figure 1 and Figure 4 shown, the channel exits 13 of the plurality of fiber channels 11 are arranged at the channel exit end according to a set rule, and the channel entrances of the plurality of fiber channels 11 are arranged at the channel entrance end according to the same rule as the channel exits 13; the spacing between each channel entrance 12 of the plurality of fiber channels 11 is greater than the spacing between each channel exit 13. This arrangement can avoid the interlacing of each fiber inside the multi-core fiber ferrule 1, making it easier for the operator to observe the arrangement of the core end faces and obtain the spatial position distribution of each core, so as to facilitate subsequent two-photon polymerization processing of three-dimensional micro optical path elements 4.

[0047] In this embodiment, the fiber channel 11 includes one multi-core channel and a plurality of single-core channels; the diameter of the channel exit end of the multi-core fiber ferrule 1 is the same as the diameter of the fiber that needs to be fanned in and out; that is, the diameter of the multi-core channel is the same as the diameter of the single-core channel.

[0048] In this embodiment, the arrangement of the exits and entrances of the fiber channel 11 is the same, and the spacing between the cores of each multi-core fiber 2 that needs to be connected to light and the cores of the single-core fiber 3 is as uniform as possible, and the spacing is as small as possible. At the same time, the diameter of the multi-core channel exit 13 is consistent with the diameter of the fiber that needs to be fanned in and out. Under normal circumstances, in order to meet the above requirements, the plurality of fiber channels 11 are arranged according to the rule of central symmetry, and the multi-core channel is located at the center, and each single-core channel is arranged at equal intervals around the fiber channel 11.

[0049] In this embodiment, at the channel entrance end of the multi-core fiber ferrule 1, the arrangement of each fiber channel 11 entrance is the same as the arrangement of the channel exit 13, and is also arranged in a central symmetric 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, and is usually greater than 1 mm.

[0050] As Figure 1 shown, for each fiber channel 11, within a certain length range from the channel exit end, each fiber channel 11 is parallel to each other, and the diameter of each fiber channel in this range is also the same. Within a range of 4-5 mm near the exit end of the channel inside the multi-core fiber 2 ferrule, it is necessary to ensure that the arrangement of each fiber channel 11 is completely consistent with the arrangement of the exit, and each fiber channel 11 is parallel to each other. This is to ensure that when the final fiber exits at the exit, each fiber exits parallel to each other without crossing.

[0051] As Figure 2 and Figure 3 shown, the three-dimensional micro-optical path element 4 and the at least two mirrors 42 on the cylindrical space waveguide 41 cooperate with each other through the two mirrors 42 to achieve a 180° turn of the light beam, and to achieve the interconnection of the light from one fiber core of the multi-core fiber 2 to the fiber core of the single-core fiber 3. As Figure 2 and Figure 3 shown, the two fiber cores to be connected are parallel to each other, and a mirror 42 at a 45° angle to the axial direction of the fiber core is machined in the axial extension direction of each fiber core, so that a 90° turn of the light can be achieved, and the cooperation of the two mirrors 42 can achieve a 180° turn of the light beam. In this embodiment, by machining the above-mentioned three-dimensional micro-optical path element 4 between all the multi-core fiber 2 fiber cores and the single-core fiber 3 to be interconnected, a complete fan-in and fan-out structure is achieved. In this application, a two-photon polymerization machining method is used to polymerize and process the photoresist to obtain the required three-dimensional micro-optical path element 4.

[0052] It should be noted that the above-mentioned three-dimensional micro-optical path element is one of the implementation manners, and the three-dimensional micro-optical path element 4 can also be a three-dimensional waveguide, a mirror, a lens, a parabolic mirror, or other combinations, as long as it can be optically interconnected and the light beam can be turned back by 180 degrees.

[0053] In this embodiment, in order to facilitate subsequent two-photon polymerization processing, at the channel exit end, the multi-core fiber 2 and each single-core fiber 3 are fixed on the multi-core fiber ferrule 1 by dropping glue and curing. The glue has high hardness after curing, and can be ground and polished to ensure that the grinding and polishing of the fiber end face can be smoothly carried out. It should be noted that in this embodiment, before the two-photon polymerization processing of the three-dimensional micro-optical path element 4, the fiber cores at the channel exit end need to be end face polished.

[0054] The multi-core fiber fan-in fan-out device provided by the embodiment is fixed in the fiber channel 11 by the multi-core fiber ferrule 1, and then the three-dimensional micro optical path element 4 is directly processed on the end face of the fiber core to be connected by using the two-photon polymerization processing method, the three-dimensional micro optical path element 4 obtained by direct polymerization processing can realize the optical interconnection between the fiber cores of the multi-core fiber 2 and the single-core fiber 3, thereby realizing the fan-in fan-out function; the multi-core fiber 2 and the single-core fiber 3 of the application are fixed in the channel of the multi-core fiber ferrule 1, which facilitates subsequent processing of the end face of each fiber core, does not require secondary coupling alignment, has low processing difficulty and high efficiency, and can meet most of the needs of the multi-core fiber fan-in fan-out device.

[0055] The multi-core fiber fan-in fan-out device provided by the embodiment, thanks to the structural design of the multi-core fiber ferrule 1, the multi-core fiber 2 and the plurality of single-core fibers 3 are arranged in a central symmetric structure, usually the multi-core fiber 2 is fixed in the middle position, and the plurality of single-core fibers 3 are arranged at equal intervals around the multi-core fiber 2; in this way, the spacing between each pair of single-core fiber 3 fiber cores to be connected and the corresponding fiber core of the multi-core fiber 2 is equal, and the three-dimensional micro optical path element 4 to be processed is also completely the same, only the angle and position are different. This can avoid the loss difference caused by structural differences as much as possible, and ensure the uniformity of each channel of the finally obtained fan-in fan-out device.

[0056] The multi-core fiber fan-in fan-out device provided by the embodiment, thanks to the structural design of the multi-core fiber ferrule 1 provided by the embodiment, the end faces of all the optical fibers are vertically exposed directly below the objective lens of the two-photon polymerization processing equipment, and in the imaging field of view, all the fiber cores are clearly visible, and the accurate position of the fiber core can be obtained through simple image recognition feature processing. When the three-dimensional micro optical path element 4 is prepared by using the two-photon polymerization processing method, high-precision active alignment coupling technology is not required, after the optical fiber is fixed in the multi-core fiber 2 ferrule by hand, it only needs to be placed into the two-photon polymerization processing equipment, and the in-situ detection technology of the equipment can complete the processing, and the processing is sequentially formed, without the need for secondary alignment coupling, and the operation process is simple.

[0057] The multi-core fiber fan-in fan-out device provided by the embodiment has small device size and high integration. The processing precision of the two-photon polymerization processing technology is very high, usually reaching 100 nm level, and can realize very precise three-dimensional structure processing. At the same time, the three-dimensional micro optical path element 4 is obtained by curing photoresist, and the outside environment is air, and the two have a large refractive index difference, combined with the 90-degree deflection transmission of the micro reflector to the light beam, the light beam transmission between the fiber cores can be realized in a very small structure, and the size of the general three-dimensional micro optical path is in the range of 100-300 μm, which has great potential for large-scale integrated applications.

[0058] Embodiment Two

[0059] This embodiment is a second embodiment of a multi-core fiber fan-in fan-out device, which is similar to Embodiment One, except that, as shown in Figure 1 a first protective shell 5 is further provided, which is sleeved outside the multi-core fiber ferrule piece 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 multi-core fiber ferrule piece 1 is located in the groove 51. The first protective shell 5 is used to protect the internal multi-core fiber ferrule piece 1 from external damage, and also serves as a fixing clamp in the case of fiber end face grinding, three-dimensional micro optical path processing by two-photon polymerization, etc. The first protective shell 5 is usually made of metal material by mechanical processing.

[0060] As shown in Figure 1 , the inside of the first protective shell 5 is provided with a cavity for accommodating the multi-core fiber ferrule piece 1, one end of which is an insertion end of the cavity, and the other end is provided with a groove 51 in communication with the cavity; the multi-core fiber ferrule piece 1 is inserted into the cavity from the insertion end until the outlet end of the channel of the multi-core fiber ferrule piece 1 is located in the groove 51 and does not protrude out of the groove 51, i.e. it plays a protective role and does not affect subsequent processing. In the groove 51, glue is added to solidify the fiber core, which can fix the fiber core and prevent glue from flowing out. Moreover, the groove 51 is designed to ensure that the glue can be better dropped to ensure the uniform thickness of each position. After the glue is solidified, it is also convenient for subsequent grinding of the fiber end face; and the three-dimensional micro optical path element 4 obtained by two-photon polymerization processing is also located in the groove 51, which can play a certain protective role.

[0061] In this embodiment, as shown in Figure 5 , a second protective shell 6 is further provided, which is a metal shell, and the second protective shell 6 is wrapped outside the first protective shell 5 to wrap the entire fan-in fan-out device in the second protective shell 6, and only an opening is provided at the inlet end of the channel for the fiber to pass through.

[0062] Embodiment Three

[0063] This embodiment is a second embodiment of a processing method of a multi-core fiber fan-in fan-out device, which is used to process the multi-core fiber fan-in fan-out device of Embodiment One or Embodiment Two, and includes the following steps:

[0064] Step S1. Preparing a multi-core fiber ferrule piece 1: using 3D printing technology, a photosensitive resin material is processed to prepare the multi-core fiber ferrule piece 1.

[0065] 3D printing technology includes but is not limited to Digital Light Processing (DLP) technology, DLP is a high-precision additive manufacturing technology based on light curing, which solidifies photosensitive resin layer by layer through dynamic projection of ultraviolet light pattern by Digital Micromirror Device (DMD).

[0066] Step S2. The outer sleeve and protective layer of one end of the multi-core optical fiber 2 and the single-core optical fiber 3 are stripped to expose the core within a specified length range; then the multi-core optical fiber 2 and the single-core optical fiber 3 are inserted into the respective optical fiber channels 11 from the channel entrance end of the multi-core optical fiber ferrule 1, and the multi-core optical fiber 2 and the single-core optical fiber 3 are pulled out from the channel exit end.

[0067] During the insertion process, the optical fiber outer sleeve is inserted into the inside of the channel entrance 12 of the multi-core optical fiber ferrule 1 to ensure that there is no unprotected bare fiber exposed to the outside. This is to protect the optical fiber, which is very fragile and prone to bending. Through the above operation, the bare fiber is protected inside the multi-core optical fiber ferrule, and the final device has good stability.

[0068] In addition, on one side of the channel entrance 12 of the multi-core optical fiber ferrule 1, ultraviolet glue is added and cured to fix the optical fiber and the multi-core optical fiber ferrule 1 together.

[0069] Step S3. Add glue at the channel exit end and cure it to fix the optical fiber pulled out from the respective optical fiber channels 11 at the channel exit end of the multi-core optical fiber ferrule 1; and ensure that the thickness of the cured glue is within a specified range and the hardness of the cured glue is within a specified range.

[0070] Typically, the thickness is in the range of 1-2mm; the glue used has a high hardness after curing, including but not limited to foundry glue, epoxy resin glue. This is to ensure that the subsequent optical fiber end face grinding process proceeds smoothly.

[0071] Step S4. Optical fiber end face grinding of the multi-core optical fiber 2 and the single-core optical fiber 3 at the channel exit end.

[0072] Grinding is performed using standard optical fiber grinding process to ensure that each optical fiber end face on the exit side has very good surface finish. During the grinding process, the glue cured at the channel exit end of the multi-core optical fiber ferrule 1 will be masked, in order to ensure the masking effect, high-hardness glue after curing is required in the previous step.

[0073] Step S5. Fix the multi-core optical fiber ferrule piece 1 processed in step S4 below the objective lens of the two-photon polymerization processing device, adjust the two-photon polymerization processing device so that the processing field covers the positions of the fiber end faces, observe the fiber end face core arrangement by the reflective microscopic imaging mode, and obtain the spatial position distribution of each core; and print a three-dimensional micro optical path element 4 between each core to be connected by the two-photon polymerization processing mode.

[0074] In this step, the channel outlet end of the ground multi-core optical fiber ferrule piece 1 is fixed directly below the objective lens of the two-photon polymerization processing device, and the two-photon polymerization processing device is adjusted so that the processing field just covers the positions of the fiber end faces. At this time, each fiber to be connected and its core is directly exposed below the objective lens of the two-photon polymerization processing device, and the fiber end face core arrangement can be observed by the reflective microscopic imaging mode to obtain the spatial position distribution of each core. Compared with the photonic wire detection mode, this mode has low detection difficulty and high detection precision.

[0075] A specific three-dimensional micro optical path element 4 is printed between each core to be connected by the two-photon polymerization processing technology, so that the light communication between each core to be connected is realized.

[0076] Step S6. Develop the three-dimensional micro optical path element 4 obtained in step S5 to remove the unnecessary photoresist that has not been polymerized, and complete the multi-core optical fiber fan-in fan-out device. The obtained three-dimensional micro optical path element 4 can realize the optical interconnection between the cores of the multi-core optical fiber 2 and the cores of the single-core optical fiber 3, thereby realizing the fan-in fan-out function.

[0077] In this embodiment, in order to facilitate the grinding of the fiber end face and the subsequent two-photon polymerization processing, a first protective shell 5 can be first sleeved on the outside of the multi-core optical fiber ferrule piece 1 before step S4. The first protective shell 5 has a certain hardness, which facilitates the clamping and fixing of the multi-core optical fiber ferrule piece 1.

[0078] In addition, after step S6, a second protective shell 6 is sleeved to protect the entire multi-core optical fiber ferrule piece and the processed three-dimensional micro structure from environmental pollution.

[0079] The processing method of the multi-core optical fiber fan-in fan-out device provided in this embodiment has the advantages of one-time forming, no need for secondary alignment, high processing efficiency, low difficulty in in-situ detection and identification, high detection precision, small structure size, high integration, simple processing process, etc., and can meet most of the needs of multi-core optical fiber fan-in fan-out devices.

[0080] As Figure 5As shown, a four-core fiber fan-in fan-out device is provided, which is used to connect four cores of a four-core fiber with 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.

[0081] As shown in the figure, the left side is the overall diagram of the final product of the four-core fiber fan-in fan-out device, and the right side is the area of the four-core fiber ferrule, the ferrule protection shell, the high-hardness glue and the three-dimensional micro optical element 4. The complete packaging of the whole device can be realized by installing a second protection shell 6 outside the ferrule protection shell. Figure 5

[0082] In the specific content of the above specific embodiments, any non-contradictory combination of technical features can be made, and in order to make the description simple, all possible combinations of the above technical features are not described, however, as long as the combination of these technical features does not exist, it should be considered as the scope of the present application.

[0083] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made. Here, it is not necessary and also impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.​

Claims

1. A multi-core optical fiber fan-in / fan-out device, characterized in that, The system includes a multi-core fiber ferrule (1), a multi-core fiber (2), multiple single-core fibers (3), and multiple three-dimensional micro-optical path elements (4). The multi-core fiber ferrule (1) has multiple fiber channels (11) inside, and the multi-core fiber (2) and the multiple single-core fibers (3) are respectively inserted into each of the fiber channels (11), with one end face of each of the multi-core fiber (2) and the single-core fiber (3) extending out of the fiber channel (11). Each core of the multi-core fiber (2) is connected to each of the single-core fibers through the three-dimensional micro-optical path elements (4). The fiber core connection of the fiber (3) is realized by the three-dimensional micro optical path element (4) to realize the optical interconnection between the fiber core of the multi-core fiber (2) and the fiber core of the single-core fiber (3), thereby realizing the fan-in and fan-out function; the three-dimensional micro optical path element (4) is directly processed on the end face of each fiber core by two-photon polymerization processing method; the fiber channel (11) includes a multi-core channel and multiple single-core channels; the multiple fiber channels (11) are arranged according to the rule of central symmetry, and the multi-core channel is located in the center, and each single-core channel is arranged at equal intervals around the fiber channel (11).

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

3. The multi-core fiber fan-in / fan-out device according to claim 2, characterized in that, The channel exits (13) of the multiple optical fiber channels (11) are arranged at the channel exit end according to a set rule, and the channel 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 value between each channel entrance (12) of the multiple optical fiber channels (11) is greater than the spacing value between each channel exit (13).

4. The multi-core fiber fan-in / 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 exit end, each of the optical fiber channels (11) is parallel to each other.

5. The multi-core fiber fan-in / fan-out device according to any one of claims 2 to 4, characterized in that, The three-dimensional micro optical path element (4) includes a cylindrical spatial waveguide and at least two mirrors located on the cylindrical spatial waveguide. The two mirrors cooperate with each other to achieve a 180° turn of the light beam, so that the light beam can be transmitted from one core of the multi-core optical fiber (2) to the core of the single-core optical fiber (3) to achieve interconnection and light transmission.

6. The multi-core fiber fan-in / fan-out device according to any one of claims 2 to 4, characterized in that, It also includes a first protective shell (5), which is sleeved on the outside of the multi-core fiber optic ferrule (1). The first protective shell (5) has a groove (51) at the channel outlet end, and the channel outlet end of the multi-core fiber optic ferrule (1) is located in the groove (51).

7. The multi-core fiber fan-in / fan-out device according to claim 5, characterized in that, At the channel outlet end, glue is applied to fix the multi-core optical fiber (2) and each of the single-core optical fibers (3) onto the multi-core optical fiber ferrule (1).

8. A method for fabricating a multi-core fiber fan-in / fan-out device according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Preparation of multi-core fiber optic ferrule (1): Using 3D printing technology, photosensitive resin material is processed to prepare multi-core fiber optic ferrule (1). S2. Strip the outer sheath and protective layer from one end of the multi-core fiber (2) and the single-core fiber (3) to expose the fiber core within a set length range; then insert the multi-core fiber (2) and the single-core fiber (3) into each fiber channel (11) in sequence from the channel entrance end of the fiber channel (11) of the multi-core fiber ferrule (1), and let the multi-core fiber (2) and the single-core fiber (3) pass out from the channel exit end; S3. Apply glue to the channel outlet end for curing, and fix the optical fibers that pass through each optical fiber channel (11) to the channel outlet end of the multi-core optical fiber ferrule (1); And ensure that the thickness and hardness of the cured adhesive are within the set range; S4. Polish the fiber end faces of the multi-core fiber (2) and single-core fiber (3) at the channel outlet. S5. Fix the multi-core fiber ferrule (1) processed in step S4 below the objective lens of the two-photon polymerization processing equipment, adjust the two-photon polymerization processing equipment, and obtain the spatial distribution of each fiber core; through two-photon polymerization processing, polymerize and print three-dimensional micro optical path elements (4) between the fiber cores that need to be connected. S6. The three-dimensional micro optical path element (4) obtained in step S5 is developed to remove the excess unpolymerized photoresist and complete the multi-core fiber fan-in and fan-out device; wherein the obtained three-dimensional micro optical path element (4) can realize the optical interconnection between the multi-core fiber (2) core and the single-core fiber (3) core, thereby realizing the fan-in and fan-out function.

9. The fabrication method of the multi-core fiber fan-in / fan-out device according to claim 8, characterized in that, In step S2, glue is dripped onto the channel entrance end of the multi-core fiber ferrule (1) and cured to fix the multi-core fiber (2) and single-core fiber (3) to the channel entrance end of the multi-core fiber ferrule (1). After step S1 and before step S4, the process also includes using a first protective housing (5) to cover the multi-core fiber optic ferrule (1).

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