WO2020019226A1

WO2020019226A1 - Optical fiber coupling method and system, optical fiber and signal transmission device

Info

Publication number: WO2020019226A1
Application number: PCT/CN2018/097153
Authority: WO
Inventors: 何俊; 张哲�; 王义平
Original assignee: 深圳大学
Priority date: 2018-07-26
Filing date: 2018-07-26
Publication date: 2020-01-30

Abstract

An optical fiber coupling method and system, an optical fiber and a signal transmission device, said method comprising: inserting an auxiliary optical fiber (22, 91) into an air fiber core of an air core photonic band-gap optical fiber (21, 92); carrying out a preset processing on a part, where the auxiliary optical fiber (22, 91) is inserted, of the air core photonic band-gap optical fiber (21, 92), so as to collapse an air hole in the part, where the auxiliary optical fiber (22, 91) is inserted, of the air core photonic band-gap optical fiber (21, 92); cutting a refractive index guiding type optical fiber (31, 921) formed by the collapse of the air hole; and connecting the refractive index guiding type optical fiber (31, 921) to a single mode optical fiber (51, 93), and thus, a new coupled fiber structure can be obtained. At the coupling part, the air core photonic band-gap optical fiber (21, 92) and the auxiliary optical fiber (22, 91) form the refractive index guiding optical fiber (31, 921) having a solid core, greatly increasing the mechanical strength of the coupling part, reducing the coupling loss between the air core photonic band-gap optical fiber (21, 92) and the single mode optical fiber (51, 93).

Description

Optical fiber coupling method, system, optical fiber and signal transmission device

Technical field

The present invention relates to the field of optical fiber technology, and in particular, to an optical fiber coupling method, system, optical fiber, and signal transmission device.

Background technique

At present, the unique photonic band-gap light-guiding mechanism of air-core photonic band-gap fibers allows light to travel in the air, avoiding the absorption and scattering problems of the core material itself. Therefore, there is no transmission window limitation in traditional glass optical fibers. It can transmit light and theoretically achieve very low loss, and is considered to be the best choice for the next generation of fiber optic communication technology.

Since most of the current optical fiber devices are based on ordinary single-mode quartz fibers, it is very important to achieve efficient optical coupling between air-core photonic bandgap fibers and ordinary single-mode fibers. However, the traditional method of arc-discharging optical fiber fusion welding air core photonic band gap fiber and ordinary single-mode optical fiber inevitably causes the air hole of air core photon band gap fiber to collapse, thereby introducing a large coupling loss. Although researchers have optimized the fusion parameters of air-core photonic bandgap fibers and ordinary single-mode fibers in the past few years, such as reducing the discharge intensity, reducing the discharge time, and shifting the center of the discharge position, etc. The coupling loss is still as high as -2dB, and more importantly, the low-strength welding results in extremely poor mechanical strength at the welding point. Therefore, a more efficient, low-loss, and high-mechanical coupling method between an air-core photonic bandgap fiber and an ordinary single-mode fiber has not yet been realized.

technical problem

The main purpose of the embodiments of the present invention is to provide an optical fiber coupling method, system, optical fiber, and signal transmission device, which can effectively reduce the coupling loss between an air-core photonic bandgap fiber and a single-mode fiber, and improve the connection position between the two. Mechanical strength.

Technical solutions

To achieve the foregoing objective, a first aspect of an embodiment of the present invention provides a fiber coupling method. The fiber coupling method includes:

Plugging an auxiliary fiber into the air core of an air-core photonic band-gap fiber, wherein the refractive index of the core material in the auxiliary fiber is higher than the refractive index of the cladding material of the air-core photon band-gap fiber;

Performing preset processing on a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber, so as to collapse an air hole of a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber, wherein, the The auxiliary fiber and the collapsed air-core photon bandgap fiber form a solid-core index-guided optical fiber, and the air hole in the air-core photon bandgap fiber that is not plugged into the auxiliary fiber is not collapsed;

Cutting the index-guided optical fiber so that the cut surface of the index-guided optical fiber is adapted to the end face of the single-mode optical fiber to be connected;

The index-guided optical fiber is connected to the single-mode optical fiber.

To achieve the foregoing objective, a second aspect of the embodiments of the present invention provides an optical fiber coupling system, where the optical fiber coupling system includes:

The first optical fiber connecting device is used to plug an auxiliary optical fiber into an air core of an air-core photonic band-gap optical fiber, wherein a refractive index of a core material in the auxiliary optical fiber is higher than a cladding of the air-core photon band-gap optical fiber Refractive index of the material

A second optical fiber connection device, configured to perform preset processing on a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber, so that a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber The air hole is collapsed, wherein the auxiliary fiber and the collapsed air-core photon band-gap fiber form a solid-core index-guided fiber, and the air-core photon band-gap fiber is not filled with the auxiliary fiber. Air holes have not collapsed;

An optical fiber cutting device, configured to cut the index-guided optical fiber so that a cutting surface of the index-guided optical fiber is matched with an end surface of a single-mode optical fiber to be connected;

A third optical fiber connection device is configured to connect the refractive index guided optical fiber and the single-mode optical fiber.

To achieve the above object, a third aspect of the embodiments of the present invention provides an optical fiber, the optical fiber includes: an auxiliary optical fiber, an air core photonic band gap optical fiber, and a single-mode optical fiber;

The refractive index of the core material in the auxiliary optical fiber is greater than the refractive index of the cladding material of the air-core photonic band gap optical fiber; the auxiliary optical fiber is located in the air core of the air-core photonic band gap optical fiber, and the auxiliary optical fiber The optical fiber is enveloped by a structure formed after the air hole of the air-core photonic band gap fiber is collapsed to form a solid core index-guided optical fiber, and the auxiliary fiber is not inserted in the air-core photonic band gap fiber. Without collapsing, the index-guided optical fiber is connected to the single-mode fiber, wherein the core of the index-guided optical fiber is connected to the core of the single-mode fiber.

In order to achieve the foregoing objective, a fourth aspect of the embodiments of the present invention provides a signal transmission device, where the signal transmission device includes the foregoing optical fiber.

Beneficial effect

Embodiments of the present invention provide an optical fiber coupling method, a system, an optical fiber, and a signal transmission device. According to the present invention, an air core photonic band gap optical fiber is plugged into an air core photon band gap optical fiber by plugging an auxiliary optical fiber into the air core of the air core photon band gap optical fiber. The auxiliary fiber is pre-set at the place where the air hole in the air-core photonic band gap fiber is inserted into the auxiliary fiber, and the refractive index guided fiber formed by cutting the air hole is cut to cut the refractive index guided fiber. The surface is adapted to the end face of the single-mode optical fiber to be connected, and the refractive index-guided optical fiber is connected to the single-mode optical fiber, and a new coupling optical fiber structure can be obtained. Coupling of the mode fiber will cause problems such as the increase of light energy loss and weak mechanical strength of the coupling part because of the collapse of the cladding symmetrical crystal structure caused by the collapse of the air hole. In the embodiment of the present invention, at the coupling portion, the air-core photon band gap fiber and the auxiliary fiber form a solid core index-guided fiber. This structure greatly increases the mechanical strength of the coupling portion and reduces the air-core photon band. Coupling loss between a gap fiber and a single-mode fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely These are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained according to these drawings without paying creative labor.

FIG. 1 is a schematic flowchart of an optical fiber coupling method according to an embodiment of the present invention;

2 is a schematic diagram of inserting an auxiliary optical fiber into an air-core photonic band-gap optical fiber according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an air discharge of an air core photon band gap fiber with an auxiliary fiber inserted in an embodiment of the present invention to collapse an air hole of the air core photon band gap fiber;

4 is a schematic diagram of cutting a refractive index guided optical fiber according to an embodiment of the present invention;

5 is a schematic diagram of connecting a refractive index guided optical fiber and a single-mode optical fiber according to an embodiment of the present invention;

6 is a schematic structural diagram of an optical fiber obtained by using the optical fiber coupling method in FIG. 1 according to an embodiment of the present invention;

7 is a schematic diagram of inserting another auxiliary optical fiber into an air-core photonic bandgap optical fiber according to an embodiment of the present invention;

8 is a schematic structural diagram of an optical fiber coupling system according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of an optical fiber according to an embodiment of the present invention.

Embodiments of the invention

In order to make the objectives, features, and advantages of the present invention more obvious and easier to understand, the technical solutions in the embodiments of the present invention will be described clearly and completely in combination with the accompanying drawings in the embodiments of the present invention. Obviously, the described The embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work fall into the protection scope of the present invention.

The existing coupling technology is used to couple the air-core photon band gap fiber and the ordinary single-mode fiber. At the coupling part, the cladding symmetrical crystal structure of the air-core photon band gap fiber is largely damaged, so the coupling part The optical energy loss is large, the transmission loss is large, and the structure of the coupling part is relatively thin, so the mechanical strength is low, which increases the difficulty of transmission and laying.

In order to solve the above problem, this embodiment proposes a fiber coupling method. By this method, an optical fiber with higher mechanical strength and lower coupling loss can be obtained. Referring to FIG. 1, the optical fiber coupling method in this embodiment includes:

Step 101: Plug an auxiliary optical fiber into an air core of an air-core photonic band-gap optical fiber, wherein a refractive index of a core material in the auxiliary optical fiber is higher than a refractive index of a cladding material of the air-core photon band-gap optical fiber;

In this embodiment, the air-core photon band-gap fiber can be air-core photon band-gap fiber of various types, specifications, and transmission bands. In order to ensure the transmission quality of the coupled fiber, the refractive index of the core in the auxiliary fiber needs to meet certain requirements. In this embodiment, the refractive index of the core material of the auxiliary fiber is slightly higher than that of the cladding material of the air-core photonic band-gap fiber, and the refractive index-guided optical fiber formed by the auxiliary fiber and the air-core photon band-gap fiber is single-mode Optical fiber for transmission. Optionally, in this embodiment, the auxiliary optical fiber is made according to a common single-mode optical fiber for communication. In one example, the auxiliary optical fiber can be made based on a common single-mode optical fiber whose refractive index of the core material is at least 0.01 higher than that of the cladding material of the air-core photonic bandgap fiber.

Optionally, the type of the auxiliary fiber includes, but is not limited to, a micro-nano fiber. The refractive index of the core material of the auxiliary fiber may be much larger than the refractive index of the cladding material of the air-core photonic bandgap fiber.

In one example, the auxiliary fiber is a single-mode fiber core for communication. In another example, the auxiliary fiber is composed of a step-index structure formed by a core and a partial cladding of the single-mode fiber. It can be understood that, in order to plug the auxiliary fiber into the air core of the air-core photonic band-gap fiber, the diameter of the auxiliary fiber must be slightly smaller than the diameter of the air core of the air-core photon band-gap fiber, that is, the auxiliary fiber of this embodiment. Gap fit with air core of air-core photonic band gap fiber. However, it can be understood that, in order to avoid insufficient mechanical strength at the coupling part, it is necessary to avoid that the gap between the auxiliary fiber and the air core of the air-core photonic band-gap fiber is too large.

In this embodiment, the step of plugging the auxiliary optical fiber into the air core of the air-core photonic band-gap optical fiber can be completed by an optical fiber fusion splicer. Specifically, the air-core photon band gap optical fiber and the auxiliary optical fiber with the cut end face are respectively placed in the left and right clamps of the optical fiber fusion splicer. Under the observation of the optical fiber fusion splicer, the motor of the optical fiber fusion splicer is adjusted to precisely control the air. The air core of the core photonic band gap fiber is aligned with the position of the auxiliary fiber, so that the auxiliary fiber is inserted into the air core of the air core photon band gap fiber. In other examples, this step can also be completed manually by the user. For example, the user fixes the auxiliary fiber and the air-core photon band-gap fiber on a precision displacement platform. Under the observation of a microscope, the auxiliary fiber is inserted into the air-core photon band-gap. Optical fiber.

Step 102: Preset processing is performed on the part where the auxiliary fiber is inserted into the air-core photonic band-gap fiber, so that the air hole in the part where the auxiliary fiber is inserted into the air-core photon band-gap fiber is collapsed, wherein the auxiliary fiber and the collapsed air core The photon band-gap fiber forms a solid-core index-guided fiber, and the air hole in the air-core photon band-gap fiber is not collapsed in the auxiliary fiber;

In step 102 described above, the purpose of the preset processing is to collapse the air holes in the air-core photonic bandgap fiber into the auxiliary fiber to form a solid core index-guided optical fiber. Therefore, the preset processing is to allow accurate positioning. A processing method for heating. The specific heating parameters depend on the melting parameters of the cladding material that isolates each air column in the air-core photonic band gap fiber. Optionally, in one example, the collapse of the air holes of the air-core photonic band gap fiber is completed by an arc discharge process.

Specifically, the above-mentioned preset processing of the part where the auxiliary fiber is inserted into the air-core photonic band gap fiber, and the collapse of the air hole in the part where the auxiliary fiber is inserted into the air-core photon band gap fiber includes the following: The part where the auxiliary fiber is plugged in the gap fiber is subjected to arc discharge treatment, so that the air hole in the part where the auxiliary fiber is plugged in the air-core photonic band gap fiber is collapsed.

Among them, the discharge parameters during arc discharge are related to the material, thickness, and number of air columns of the air-core photonic bandgap fiber. Discharge parameters include, but are not limited to, discharge intensity, discharge duration, and the like. During the formation of a solid-core index-guided optical fiber, it is necessary to align the different positions of the air-core photonic bandgap fiber (the part where the auxiliary fiber is inserted) for arc discharge treatment (one position may require multiple discharges). Optionally, the discharge parameters of each discharge can be adjusted according to actual needs.

For example, in this embodiment, when an optical fiber fusion splicer is used to perform arc discharge on the air-core photon bandgap fiber inserted into the auxiliary fiber, the discharge power can be selected on the optical fiber fusion splicer: "standard-50bit", the discharge time: "400ms", according to the setting The discharge parameters are used to discharge a collapsed position on the air-core photon bandgap fiber. The number of discharges to the same collapsed position is generally 3-5. The actual number of repeated discharges depends on the actual collapse condition. This embodiment You can set the parameters of each discharge through the optical fiber fusion splicer. After a position of the optical fiber collapses, the optical fiber can be moved axially for a certain distance, such as about 50 microns, and then the position of the optical fiber adjacent to the current collapsed position that has not collapsed is discharged and collapsed.

In this embodiment, in order to avoid that the position where the auxiliary fiber is not inserted in the air-core photonic bandgap fiber also collapses, which causes transmission loss, the length of the auxiliary fiber inserted into the air-core photon bandgap fiber is sufficiently long, for example, not less than 4cm, etc. . Further, a portion of the auxiliary optical fiber inserted into the air-core photon band-gap fiber is longer than a portion of the air-core photon band-gap fiber that is collapsed.

The process of collapsing the air-core photon band-gap optical fiber with the auxiliary optical fiber to obtain a solid core index-guided optical fiber will be described with reference to FIGS. 2 and 3 as an example.

FIG. 2 is a schematic diagram of inserting an auxiliary optical fiber into an air-core photonic band-gap fiber, and FIG. 3 is a schematic diagram of an air discharge of the air-core photon band-gap fiber to collapse an air hole of the air-core photon band-gap fiber.

In FIG. 2, 21 is an air-core photonic band gap fiber, and 22 is an auxiliary fiber. In Fig. 2, one end of the auxiliary optical fiber penetrates into the air-core photonic bandgap fiber is A end and the other end is B end. The structure of the auxiliary optical fiber in Fig. 2 is a step refractive index structure composed of a core and a partial cladding. The light gray part of the outer layer of the auxiliary fiber 22 is the cladding, and the darker part of the inner layer is the single-mode fiber core.

When the air core photon bandgap fiber is collapsed in this embodiment, it can start from the vicinity of the A end, and then sequentially collapse the air holes of the air core photon bandgap fiber in the direction from the A end to the B end. Each time a position is collapsed, two The matched optical fibers (21 and 22) are moved to the left by the length of the currently collapsed position, and then continue to discharge to collapse the next uncollapsed position; this embodiment can also start near the B end, and then follow the direction from the B end to the A The direction of the end collapses the air holes of the air-core photonic band-gap fiber in order, and this embodiment has no limitation on this. Optionally, the auxiliary fiber having a certain length (for example, not less than a preset length) from the A end is not collapsed corresponding to the air core photonic band gap fiber. After the arc discharge, the collapsed structure of the air hole of the air-core photonic band-gap fiber tightly wraps the auxiliary fiber to form a solid-core index-guided fiber as shown at 31 in FIG. 3.

Step 103: Cut the index-guided optical fiber so that the cutting surface of the index-guided optical fiber is matched with the end face of the single-mode fiber to be connected;

In order to facilitate the connection between the index-guided optical fiber and the single-mode fiber, the index-guided optical fiber needs to be cut. Optionally, a fiber cutter can be used for cutting, or a femtosecond laser can be used for cutting. When a fiber cutter is used, the parameters of the fiber cutter can be adjusted according to actual needs.

In this embodiment, for the remainder of the index-guided optical fiber after cutting, the subsequent steps can be continued. In step 102, the length of the index-guided optical fiber must meet certain requirements, for example, the length of the index-guided optical fiber is not less than Preset length threshold.

To facilitate subsequent connection, optionally, as shown in FIG. 4, the cutting surface of the index-guided optical fiber after cutting is perpendicular to its axis.

Step 104: Connect the index-guided optical fiber and the single-mode optical fiber.

In an example of this embodiment, the index-guided optical fiber and the single-mode optical fiber can be connected by fusion splicing. Optionally, the connection of the index-guided optical fiber and the single-mode optical fiber includes: the index-guided optical fiber is fused by fusion. Connect with single-mode fiber.

In order to facilitate welding, as shown in FIG. 5, the index-guided optical fiber 31 is aligned with the core of the single-mode fiber 51 to be connected (the end face of the single-mode fiber is also perpendicular to its own axis), so that the axes of the two are at On a straight line, and then weld. In this embodiment, the fusion parameters of the ordinary single-mode fiber can be used to fuse the index-guided optical fiber and the single-mode fiber to obtain a coupled optical fiber as shown in FIG. 6.

In an example of this embodiment, the auxiliary fiber is a single-mode fiber core for communication (the single-mode fiber here is different from the single-mode fiber connected to the index-guided fiber in step 104), and the auxiliary fiber is inserted into the air-core photon. The air core of the band gap fiber also includes:

The fiber cladding of the optical fiber to be used is etched by a predetermined chemical etching method to obtain an optical fiber core as an auxiliary optical fiber.

The optical fiber to be used is a common single-mode optical fiber for communication. Optionally, the preset chemical etching method in this embodiment includes, but is not limited to, using a hydrofluoric acid to etch the optical fiber cladding. In this embodiment, the cladding material of the optical fiber to be used can be completely etched by controlling the corrosion parameters (including, but not limited to, the concentration of the acid, the duration of the etch, etc.) while keeping the optical fiber core from being etched.

In another example of this embodiment, the auxiliary fiber is composed of a core of a single-mode fiber and a step refractive index structure formed by a part of the cladding. The auxiliary fiber is inserted into the air core of the air-core photonic band gap fiber before :

The optical fiber to be used is etched by a predetermined chemical etching method to obtain an auxiliary optical fiber having a step refractive index structure formed by a core and a partial cladding of a single-mode optical fiber.

The optical fiber to be used is a common single-mode optical fiber for communication. Optionally, the preset chemical etching method in this embodiment includes, but is not limited to, using a hydrofluoric acid to etch a part of the optical fiber cladding. In this embodiment, the auxiliary optical fiber can be obtained by controlling the corrosion parameters (including but not limited to the type of acid, the concentration, the duration of the etching, etc.) to incompletely etch the cladding of the optical fiber to be used.

In this embodiment, before corroding the optical fiber cladding of the optical fiber to be used, a layer structure other than the optical fiber cladding on the optical fiber to be used, such as a coating layer, may be stripped by a fiber clamp to perform subsequent etching operations.

In this embodiment, when an auxiliary optical fiber is directly prepared from a single-mode optical fiber with a complete structure, an uncorroded optical fiber with a complete optical fiber structure (such as 71 in FIG. 7) can be retained at one end of the auxiliary optical fiber, which can facilitate optical fiber splicing. The machine clamps the auxiliary fiber and inserts it into the air core of the air-core photonic band gap fiber.

It can be understood that after the fiber is etched, the auxiliary fiber needs to be subjected to steps such as acid neutralization.

In order to solve the problems in the prior art, this embodiment also provides an optical fiber coupling system. As shown in FIG. 8, the optical fiber coupling system includes:

The first optical fiber connection device 81 is configured to plug an auxiliary optical fiber into an air core of an air-core photonic band-gap optical fiber, wherein the refractive index of the core material in the auxiliary optical fiber is higher than that of the cladding material of the air-core photon band-gap optical fiber. Refractive index

The second optical fiber connection device 82 is configured to perform preset processing on the part where the auxiliary fiber is inserted into the air-core photonic band-gap fiber, so as to collapse the air hole in the part where the auxiliary fiber is inserted into the air-core photon band-gap fiber. The optical fiber and the collapsed air-core photon band-gap fiber form a solid core index-guided optical fiber, and the air hole in the air-core photon band-gap fiber is not collapsed in the auxiliary fiber;

An optical fiber cutting device 83, configured to cut an index-guided optical fiber so that a cutting surface of the index-guided optical fiber is adapted to an end surface of a single-mode optical fiber to be connected;

The third optical fiber connecting device 84 is configured to connect the refractive index guided optical fiber and the single-mode optical fiber.

Optionally, the first optical fiber connection device, the second optical fiber connection device, and the third optical fiber connection device are all optical fiber fusion splicers. The optical fiber fusion splicer is specifically used to perform arc discharge on the air core photonic band gap optical fiber in which the auxiliary optical fiber is inserted. Treatment, to collapse the air hole in the air core photon band gap fiber into the auxiliary fiber, and to connect the index-guided fiber and the single-mode fiber by fusion welding.

Optionally, the auxiliary optical fiber is a fiber core of a single-mode optical fiber, or the auxiliary optical fiber is composed of a step-index structure formed by a core and a partial cladding of the single-mode optical fiber.

Further, the optical fiber coupling system of this embodiment further includes: a preparation device for etching the optical fiber cladding of the optical fiber to be used by a predetermined chemical etching method to obtain the optical fiber core of the single-mode optical fiber as an auxiliary optical fiber; or The chemical etching method is used to etch the optical fiber to be used to obtain an auxiliary optical fiber composed of a step-index structure formed by a core and a partial cladding of a single-mode optical fiber. Before the preparation device corrodes the optical fiber cladding of the optical fiber to be used, the layer structure other than the upper cladding of the optical fiber to be used, such as a coating layer, can be peeled off with an optical fiber clamp.

Optionally, the type of the auxiliary optical fiber in this example includes a micro-nano fiber. The part of the auxiliary fiber inserted into the air-core photonic band-gap fiber is longer than the collapsed part of the air-core photon band-gap fiber.

In order to solve the problems in the prior art, this embodiment further provides an optical fiber, which can be obtained through the optical fiber coupling method in the foregoing example. As shown in FIG. 9, the optical fiber includes: an auxiliary fiber 91, an air-core photon band-gap fiber 92, and a single-mode fiber 93; the structure on the left of the dotted line in FIG. 9 can be considered to be formed by the auxiliary fiber 91 and the air-core photon band-gap fiber 92. The structure including the refractive index guided optical fiber 921 and the structure on the right side of the dotted line can be regarded as the single-mode optical fiber 93.

The refractive index of the core material in the auxiliary optical fiber 91 is greater than the refractive index of the cladding material of the air-core photonic band-gap optical fiber 92; the auxiliary optical fiber 91 is located in the air core of the air-core photonic band-gap optical fiber 92, and the auxiliary optical fiber 91 is exposed to air-core photons The structure formed after the air holes of the band gap optical fiber 92 are collapsed to form a solid core refractive index guided optical fiber 921, and the portion of the air core photonic band gap optical fiber that is not plugged into the auxiliary fiber is not collapsed, and the refractive index guided optical fiber 921 is not collapsed. It is connected to the single-mode optical fiber 93, and the core of the index-guided optical fiber 921 is connected to the core of the single-mode optical fiber 93.

Among them, the auxiliary fiber 91 is an optical fiber core of a single-mode fiber, or the auxiliary fiber is composed of a step-index structure formed by a core and a partial cladding of the single-mode fiber. For the preparation method of the auxiliary optical fiber, reference may be made to the description of other examples, and this example is not repeated here.

The auxiliary fiber in this example is a common single-mode fiber for communication, and its type includes, but is not limited to, micro-nano fiber. A solid-core index-guided fiber formed by an auxiliary fiber and an air-core photonic band-gap fiber is a single-mode fiber.

In this example, when the index-guided optical fiber 921 and the single-mode optical fiber 93 are connected, the two end surfaces in contact with each other are matched (the area sizes are not necessarily equal). In this example, the core of the index-guided fiber can be connected to the single-mode fiber by fusion splicing. The splicing parameters are the splicing parameters of ordinary single-mode optical fibers.

In this example, the portion of the auxiliary fiber 91 that is plugged into the air-core photonic band-gap fiber 92 is longer than the collapsed portion of the air-core photon band-gap fiber.

Further, this embodiment further provides a signal transmission device, which includes the optical fiber in the above example (such as the optical fiber in FIG. 9).

With the solution in this embodiment, the auxiliary fiber can be preset into the air core photon band gap fiber by inserting the auxiliary fiber into the air core of the air core photon band gap fiber, so that the air core photon Collapse of the air hole in the band gap fiber where the auxiliary fiber is inserted, and cutting the index-guided fiber so that the cutting surface of the index-guided fiber matches the end face of the single-mode fiber to be connected, and the index-guided fiber By connecting with single-mode fiber, a new coupling fiber structure can be obtained. Compared to the coupling of air-core photonic band-gap fibers with ordinary single-mode fibers using the existing technology, the cladding symmetry crystal structure will be damaged due to the collapse of air holes. Problems such as increased light energy loss, and weak mechanical strength at the coupling site are caused. In the embodiment of the present invention, at the coupling part, the air core photonic band gap fiber and the auxiliary fiber form a solid core refractive index guided fiber, which reduces the coupling loss caused by the collapse of the air hole in the prior art, thereby realizing air The high-efficiency, high-mechanical coupling of the core photon bandgap fiber and ordinary single-mode fiber reduces the transmission loss of optical signals.

In the several embodiments provided in this application, it should be understood that the disclosed devices, systems, and methods may be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of modules is only a logical function division. In actual implementation, there may be another division manner. For example, multiple modules or components may be combined or integrated. To another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or modules, which may be electrical, mechanical or other forms.

It should be noted that, for the foregoing method embodiments, for simplicity of description, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence. Because according to the present invention, certain steps may be performed in another order or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

In the above embodiments, the description of each embodiment has its own emphasis. For a part that is not described in detail in an embodiment, reference may be made to related descriptions in other embodiments.

The above is a description of an optical fiber coupling method, system, optical fiber, and signal transmission device provided by the present invention. For those skilled in the art, according to the ideas of the embodiments of the present invention, the specific implementation and application range will be changed. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

An optical fiber coupling method, comprising:

Inserting an auxiliary optical fiber into an air core of an air-core photonic band gap optical fiber, and a refractive index of a core material in the auxiliary optical fiber is higher than a refractive index of a cladding material of the air-core photonic band gap optical fiber;

Performing preset processing on a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber, so as to collapse an air hole of a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber, wherein, the The auxiliary fiber and the collapsed air-core photon bandgap fiber form a solid-core index-guided optical fiber, and the air hole in the air-core photon bandgap fiber that is not plugged into the auxiliary fiber is not collapsed;

Cutting the index-guided optical fiber so that the cut surface of the index-guided optical fiber is adapted to the end face of the single-mode optical fiber to be connected;

The index-guided optical fiber is connected to the single-mode optical fiber.
The optical fiber coupling method according to claim 1, wherein the auxiliary fiber is a fiber core of a single-mode fiber, and the step of inserting the auxiliary fiber into the air core of the air-core photonic band-gap fiber further comprises:

The fiber cladding of the optical fiber to be used is etched by a predetermined chemical etching method to obtain an optical fiber core as an auxiliary optical fiber.
The optical fiber coupling method according to claim 1, wherein the auxiliary optical fiber comprises a step-index structure formed by a core and a partial cladding of a single-mode optical fiber, and the auxiliary optical fiber is inserted into an air-core photonic band The air core of the gap fiber also includes:

The optical fiber to be used is etched by a preset chemical etching method to obtain an auxiliary optical fiber composed of a step-index structure formed by a core and a partial cladding of a single-mode optical fiber.
The optical fiber coupling method according to claim 1, wherein the type of the auxiliary optical fiber comprises a micro-nano fiber.
The optical fiber coupling method according to any one of claims 1 to 4, wherein a portion of the auxiliary optical fiber inserted into the air-core photon band-gap fiber is longer than a portion of the air-core photon band-gap fiber that is collapsed.
The optical fiber coupling method according to any one of claims 1 to 4, wherein the connecting the index-guided optical fiber and the single-mode optical fiber comprises:

The index-guided optical fiber and the single-mode optical fiber are connected by fusion welding.
The optical fiber coupling method according to any one of claims 1 to 4, wherein the pre-processing is performed on a part of the air core photonic band gap fiber that is plugged into the auxiliary fiber, so that the air core The collapse of the air hole in the photon band-gap fiber at the part where the auxiliary fiber is plugged includes:

Arc discharge treatment is performed on the air core photon bandgap optical fiber to which the auxiliary fiber is plugged, so that the air hole in the air core photon bandgap optical fiber to which the auxiliary fiber is plugged is collapsed.
An optical fiber coupling system, comprising:

The first optical fiber connecting device is used to plug an auxiliary optical fiber into an air core of an air-core photonic band-gap optical fiber, and a refractive index of a core material in the auxiliary optical fiber is higher than a cladding material of the air-core photon band-gap optical fiber. Refractive index

A second optical fiber connection device, configured to perform preset processing on a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber, so that a part of the air-core photon bandgap fiber that is plugged into the auxiliary fiber The air hole is collapsed, wherein the auxiliary fiber and the collapsed air-core photon band-gap fiber form a solid-core index-guided fiber, and the air-core photon band-gap fiber is not filled with the auxiliary fiber. Air holes have not collapsed;

An optical fiber cutting device, configured to cut the index-guided optical fiber so that a cutting surface of the index-guided optical fiber is matched with an end surface of a single-mode optical fiber to be connected;

A third optical fiber connection device is configured to connect the refractive index guided optical fiber and the single-mode optical fiber.
An optical fiber, characterized in that the optical fiber includes: an auxiliary optical fiber, an air-core photonic band gap optical fiber, and a single-mode optical fiber;

The refractive index of the core material in the auxiliary optical fiber is greater than the refractive index of the cladding material of the air-core photonic band gap optical fiber; the auxiliary optical fiber is located in the air core of the air-core photonic band gap optical fiber, and the auxiliary optical fiber The optical fiber is enveloped by a structure formed after the air hole of the air-core photonic band gap fiber is collapsed to form a solid core index-guided optical fiber, and the auxiliary fiber is not inserted in the air-core photonic band gap fiber. Without collapsing, the index-guided optical fiber is connected to the single-mode fiber, wherein the core of the index-guided optical fiber is connected to the core of the single-mode fiber.
A signal transmission device, comprising: the optical fiber according to claim 9.