CN109581598B - A coaxial dual waveguide fiber optic connector - Google Patents

Abstract

The invention provides a coaxial double-wave optical fiber connector. The method is characterized in that: the optical fiber connector consists of a standard single-mode optical fiber, a multi-core optical fiber connector, a multi-core optical fiber and a coaxial double-wave optical fiber. In the system: one end of the multi-core fiber is connected with each fiber core and the single-mode fiber through the multi-core fiber connector, the other end of the multi-core fiber and the coaxial double-waveguide fiber are subjected to tapering cutting, and the two are welded after geometric structural parameters are adjusted, so that the connection of the multi-core fiber middle core and the coaxial double-waveguide fiber middle core, and the connection of the multi-core fiber offset fiber core and the coaxial double-waveguide fiber ring core are realized. The invention can be used for the optical path connection of coaxial double-waveguide optical fibers.

Description

A coaxial dual waveguide fiber optic connector

(1) Technical field

The invention relates to a coaxial dual-waveguide optical fiber connector, which belongs to the technical field of optical fiber devices.

(2) Background technology

In recent years, with the demands of communication and sensing applications, a variety of specialty fibers have been invented. For example, a suspended core fiber with a microporous structure, a multi-core fiber with multiple core waveguides, a ring-core fiber with a ring-waveguide core, a Bragg fiber, a coaxial dual-waveguide fiber, and the like. Although these special fibers have great application potential and great economic value, due to the special structure of these fibers, their optical path connections are not like standard single-mode fibers, which can be easily welded by ordinary commercial fiber welding machines. . Therefore, the efficient and low-loss connection of these special fibers and standard fibers is the key to their widespread application.

Patent CN101825741B proposes a coaxial dual-waveguide optical fiber, which has an intermediate core waveguide and a coaxially distributed annular core waveguide. This coaxial dual-waveguide fiber has been widely used in subsequent development. For example, patent CN101907743B proposes to use this coaxial dual-waveguide fiber to prepare a kind of throughput optical fiber optical tweezers, which can be used for capturing, throughput and oscillation of tiny particles such as cells; patent CN106770167A proposes to use coaxial dual-waveguide fiber to prepare a kind of optical fiber tweezers. An optical tweezers fiber Raman probe, which can capture and capture cells stably at the same time excite and collect Raman spectra of cells, and has great application prospects in the analysis of cellular biological components; in the article "Fiber based optical gun for particle Shooting" proposed a light gun based on coaxial dual-waveguide fiber for the directional ejection of cell particles, which provides a new method for cell manipulation (Deng H, Zhang Y, Yuan T, et al. .Fiberbased optical gun for particle shooting[J].Acs Photonics,2017,4(3).).

In the application of the existing coaxial dual-waveguide fiber, there are generally two methods for coupling and injecting light into the two core waveguides: fusion taper coupling and side throw coupling. Fused taper coupling means that after welding the intermediate core of the coaxial dual-waveguide fiber and the standard single-mode fiber, the coaxial dual-waveguide fiber is fused and tapered, so that the light of the intermediate core is coupled into the annular core. This method makes the fiber become Very thin, the mechanical strength is greatly reduced, and the optical power within the two core waveguides is difficult to control independently. Side-throwing coupling is to align the coaxial dual-waveguide fiber and the single-mode fiber after side-throwing. One end of the dual-axis waveguide fiber is welded to the standard single-mode fiber to realize the optical path coupling of the middle core. However, the side throw coupling has strict requirements on the fiber side throw technology and the optical fiber alignment packaging technology, and is greatly affected by the external environment and has poor stability.

(3) Contents of the invention

The purpose of the present invention is to provide a coaxial dual-waveguide optical fiber connector with simple and compact structure, good stability, independent control of two core waveguides and high coupling efficiency.

The object of the present invention is achieved in this way:

A coaxial dual-waveguide optical fiber connector is characterized in that it is composed of a standard single-mode optical fiber, a multi-core optical fiber connector, a multi-core optical fiber and a coaxial dual-waveguide optical fiber. In the system: one end of the multi-core optical fiber is connected with the single-mode optical fiber through the multi-core optical fiber connector, and the other end of the multi-core optical fiber and the coaxial dual-waveguide optical fiber adjust the geometrical parameters, so that the position of the core is matched. After welding, the intermediate core of the multi-core optical fiber and the intermediate core of the coaxial dual-waveguide optical fiber, the offset core of the multi-core optical fiber and the annular core of the coaxial dual-waveguide optical fiber are connected.

The coaxial dual-waveguide optical fiber has an intermediate core waveguide and a coaxial annular core waveguide.

The multi-core optical fiber has an intermediate core waveguide and one or more offset core waveguides distributed coaxially and circumferentially.

In the coaxial dual-waveguide optical fiber connector, when the center distance between the center core and the offset core of the multi-core fiber is equal to the center distance between the center core and the annular core of the coaxial dual-waveguide fiber, the two are directly welded. Optical fiber; when the center distance between the center core and the offset core of the multi-core fiber is not equal to the center distance between the center core and the annular core of the coaxial dual-waveguide fiber, the multi-core fiber and the coaxial dual-waveguide fiber are fused and tapered , carry out size adjustment, and realize the matching of geometrical parameters before welding.

The described coaxial dual-waveguide optical fiber connector, wherein the multi-core optical fiber realizes the connection between each fiber core and the standard single-mode optical fiber through the commercialized multi-core optical fiber connector, so that each optical path can be individually controlled.

The preparation method of the coaxial dual-waveguide optical fiber connector is as follows:

Step 1: Select and connect the appropriate multi-core optical fiber and multi-core optical fiber connector, so that each core of the multi-core optical fiber is connected with the standard single-mode optical fiber, so as to realize the individual control of the optical path of each core of the multi-core optical fiber;

Step 2: The multi-core optical fiber and the coaxial dual-waveguide optical fiber are respectively melted and tapered, and the optical fiber structure size at the taper waist of the two is adjusted to match. In order to ensure the mechanical strength of the optical fiber, the diameter of the taper waist of the two tapers should not be too thin, and the fiber core can still transmit the beam with low loss;

Step 3: Cut the two fibers at the taper waist and weld them in alignment with the cores, so that the middle core of the multi-core fiber and the middle core of the coaxial dual-waveguide fiber are aligned and connected, and the offset core of the multi-core fiber is connected to the coaxial core. The toroidal cores of the dual waveguide fiber are connected in alignment.

Compared with the method for the fusion and taper coupling of the coaxial dual-waveguide optical fiber, the invention does not need to draw the optical fiber very thin, which ensures the mechanical strength of the optical fiber device, and realizes the independent optical path control of the annular core waveguide and the intermediate core waveguide. Compared with the side throw coupling method, the present invention has better stability and simpler preparation method. Therefore, the present invention has the advantages of simplicity and compactness, good stability, independent control of the two core waveguides, and high coupling efficiency.

(4) Description of drawings

FIG. 1 is a schematic structural diagram of a coaxial dual-waveguide optical fiber connector, and a partial enlarged view corresponding to the connection between the multi-core optical fiber and the coaxial dual-waveguide optical fiber in the dashed frame.

Fig. 2(a) is a structural view of the end face of the coaxial dual waveguide fiber, and Fig. 2(b) is the refractive index distribution at the dotted line of the end face.

Fig. 3(a) is a structural diagram of the end face of the twin-core optical fiber, and Fig. 3(b) is the refractive index distribution at the dashed line of the end face of the twin-core optical fiber.

Figure 4 is a view of the end face structure of a variety of multi-core optical fibers that can be used, Figure 4 (a) three-core optical fiber, Figure 4 (b) four-core optical fiber, Figure 4 (c) five-core optical fiber.

FIG. 5 shows the simulation result of injecting light from the eccentric core of the twin-core fiber into the annular core of the coaxial dual-waveguide fiber when the twin-core fiber is used as the input fiber.

FIG. 6 shows the simulation results of injecting light into the annular core of the coaxial dual-waveguide fiber from the four eccentric cores of the five-core fiber when the five-core fiber is used as the input fiber.

FIG. 7 is a schematic diagram of cutting and welding of coaxial dual-waveguide optical fibers after adjusting the structure and size of the eccentric dual-core optical fiber fusion taper.

FIG. 8 is a schematic diagram of cutting and welding of the eccentric dual-core optical fiber after the structure and size of the coaxial dual-waveguide optical fiber fusion taper is adjusted.

(5) Specific implementation manner

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

1 is a schematic diagram of the structure of the coaxial dual-waveguide optical fiber connector according to the present invention. The end face structure diagram of the coaxial dual waveguide fiber 1 is shown in Fig. 2(a), which has an intermediate fiber core 1-1 and a coaxially distributed annular core 1-2, and Fig. 2(b) is Fig. 2 ( a) The refractive index distribution at the dotted line in the middle, the refractive index difference between the central core and the annular core and the cladding can be the same or different. The end face structure diagram of the adopted twin-core optical fiber is shown in Fig. 3(a), which has an intermediate core 2-1 and an offset core 2-2. Similarly, Fig. 3(b) is Fig. 3(a) ) is the refractive index profile at the dashed line. In fact, the twin-core fiber can also be replaced by other multi-core fibers, such as the three multi-core fibers shown in Figure 4, these fibers have a central core and a plurality of offset cores distributed coaxially and circumferentially. The middle core of the multi-core fiber is connected to the coaxial dual-waveguide fiber, and the offset peripheral fiber core is connected to the annular core of the coaxial dual-waveguide fiber.

Example 1:

The description of this embodiment is performed using a twin-core optical fiber. When the center distance between the center core 2-1 and the offset core 2-2 of the twin-core fiber 2 is the same as the center distance between the center core 1-1 and the annular core 1-2 of the coaxial dual-waveguide fiber 1, it can be directly The twin-core optical fiber 2 and the coaxial dual-waveguide optical fiber 1 are directly welded to the core, as shown in the partial enlarged view in the dashed-line frame in FIG. 1 .

In order to describe the connection effect of the present invention, the simulation analysis of the coaxial dual-waveguide optical fiber connector using the dual-core optical fiber is carried out. The simulation results are shown in Figure 5, in which Figure 5(a) represents the input beam from the eccentric 2-2 of the twin-core fiber 2 at z=0μm, and Figures 5(b), (c) and (d) represent the The light beams in the eccentric, after being input into the annular core 1-2 of the coaxial dual-waveguide fiber, transmit light fields at z=500 μm, z=1000 μm and z=4000 μm. It can be seen that after the light beam enters the annular core 1-2 of the coaxial dual-waveguide fiber from the eccentric core 2-2 of the dual-core fiber, it is basically all bound and transmitted in the annular core 1-2, and the optical field is transmitted along the Gaussian optical field. Spread around the ring core 1-2 until it fills the inside of the ring core. Since the single-wavelength coherent beam is used in the simulation, multi-mode interference will occur when the beam propagates in the annular core 1-2, forming a beam splitting phenomenon, as shown in Figure 5(d). However, in the application of the coaxial dual-waveguide fiber, the incoherent beam can be used as the input beam in the annular core to avoid the splitting phenomenon.

Since the above-mentioned dual-core fiber is used, which contains only one biased fiber core 2-2, the light beam in the biased core 2-2 will still appear axisymmetric in the light field after transmitting a certain distance in the input annular core. , which will affect the application of coaxial dual-waveguide optical fibers (for example, in the application of optical fiber optical tweezers, the annular optical field is required to be symmetrically and uniformly distributed, CN101907743B). In this case, a multi-core fiber having a plurality of offset cores distributed axially and coaxially can be used as the input fiber. As shown in Fig. 6, a five-core fiber is used as the input fiber, in which Fig. 6(a) represents the input beam from the four eccentric cores 5-2 of the five-core fiber at z=0μm, Fig. 6(b), (c) ) and (d) respectively represent the transmission light field at z=500μm, z=1000μm and z=4000μm after the beam in the eccentric 5-2 is input into the annular core 1-2 of the coaxial dual waveguide fiber, it can be seen that In the process of transmission in the annular core 1-2, the light output field always maintains an axisymmetric distribution.

Example 2:

The description of this embodiment is performed using a twin-core optical fiber. When the center distance between the center core and the offset core of the twin-core fiber 2 is not equal to the center distance between the center core and the annular core of the coaxial dual-waveguide fiber 1, the structure size of the fiber needs to be adjusted by the method of melting taper. Fine-tune it to match. In order to ensure the mechanical strength of the optical fiber, the diameter of the taper waist of the two tapers should not be too thin, and the fiber core can still transmit the light beam with low loss. Figure 7 is a schematic diagram of cutting and welding the coaxial dual-waveguide fiber after the structure and size of the eccentric double-core fiber fusion taper is adjusted. Part 3 is the fusion taper, and the size adjustment area. Figure 8 is a schematic diagram of cutting and welding of the eccentric dual-core optical fiber after the structure and size adjustment of the coaxial dual-waveguide fiber fused taper. Part 3 is the fused taper, and the size adjustment area.

Claims (2)

1. a coaxial dual-waveguide optical fiber connector, is characterized in that: it is made up of standard single-mode optical fiber, multi-core optical fiber connector, multi-core optical fiber and coaxial dual-waveguide optical fiber; in the described composition: one end of the multi-core optical fiber The connection between each fiber core and the single-mode fiber is realized through a multi-core fiber connector. The other end of the multi-core fiber and the coaxial dual-waveguide fiber adjust the geometrical parameters so that the positions of the cores are matched and then welded. Coaxial dual waveguide fiber intermediate core, multi-core fiber offset core and coaxial dual waveguide fiber ring core connection; The coaxial dual-waveguide optical fiber has an intermediate core waveguide and a coaxial annular core waveguide; The multi-core optical fiber has an intermediate core waveguide and one or more offset core waveguides distributed coaxially and circumferentially. 2. A kind of coaxial dual-waveguide optical fiber connector according to claim 1, it is characterized in that: when the center distance of the middle core and the offset core of the multi-core fiber is the same as the center core and the annular center of the coaxial dual-waveguide fiber When the center-to-center spacing of the cores is equal, the two fibers are directly welded; when the center-to-center distance between the center core and the offset core of the multi-core fiber is not equal to the center-to-center spacing between the center core and the annular core of the coaxial dual-waveguide fiber, the The optical fiber and the coaxial dual-waveguide optical fiber are fused and tapered, and the size is adjusted to achieve the matching of geometrical parameters before welding.

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