KR20120080480A - Plastic optical fiber coupler - Google Patents

Abstract

PURPOSE: A plastic optical fiber coupler is provided to easily expand I/O channels as well as be easily manufactured and have a simple structure. CONSTITUTION: A plastic optical fiber coupler(100) comprises a base block(110), an input channel part(120), an output channel part(130), and a dispersion polymer layer(140). A light guide groove guides light to an upper side of the base block along a longitudinal direction. The input channel part mounts one or more input plastic optical fibers at one end of the base block within the light guide groove. The output channel part mounts a plurality of output plastic optical fibers to be separated from the input plastic optical fibers at the other end of the base block within the light guide groove. The dispersion polymer layer is filled within the light guide groove and disperses the light coming out through the input plastic optical fibers. The dispersion polymer layer distributes the light to the output plastic optical fibers.

Description

Plastic optical fiber coupler

The present invention relates to a plastic optical fiber coupler, and more particularly, to a plastic optical fiber coupler that is easy to manufacture and simple in structure.

Communication optical fiber is divided into single mode fiber and multimode fiber according to the optical signal transmission mode.

Most of the long-distance high-speed communication optical fibers currently used are step-index single-mode optical fibers based on quartz glass, and glass optical fibers have a diameter of 125 µm, especially core (optical signal transmission area). core) diameter is usually only 8-10㎛. Therefore, such glass optical fibers are very difficult to align and connect, resulting in high cost loss. On the other hand, a multimode glass fiber having a larger core diameter than a single mode fiber can be used for short distance communication such as a LAN, but it is difficult to be widely used due to the high cost and fragility of the connection.

Thus, metal wires, such as twisted pairs or coaxial cables, have been used primarily for short-range communications within 200m, such as LANs. However, metal wires cannot reach the future transfer rate standards because they cannot reach 625 Mbps, which is the Asynchronous Transfer Mode (ATM) standard of the 2000s because the information transfer rate or transmission bandwidth is only about 150 Mbps.

For this reason, a lot of efforts and investments continue to develop optical fibers made of polymer materials that can be used for short-range communication such as LAN. Because of the flexibility of polymer materials, plastic optical fibers can reach 0.5 to 1.0 mm in diameter 100 times larger than glass optical fibers, making them easy to align or connect. Savings are possible.

Such plastic optical fibers have been widely used for short-range data communications including home networks, automotive optical communications, optical sensing systems, and the like.

On the other hand, in the optical communication using a plastic optical fiber, an optical coupler is required for the coupling and distribution of signals. By the way, the conventional plastic optical fiber coupler uses a manufacturing method such as twine and fusion, side polishing, chemical etching, cutting and bonding, thermal deformation, molding, etc., but the manufacturing process is complicated, manufacturing costs are high.

The present invention has been made to improve the above problems, and an object thereof is to provide a plastic optical fiber coupler that is easy to manufacture and simple in structure.

Plastic optical coupler according to the present invention in order to achieve the above object is formed of a transparent synthetic resin material and the base block is formed with an optical guide groove for guiding light along the longitudinal direction on the upper surface; An input channel part in which at least one input plastic optical fiber is mounted in the optical guide groove at one end of the base block; An output channel unit having a plurality of output plastic optical fibers mounted in the optical guide groove at the other end of the base block to be spaced apart from the input plastic optical fiber; And a dispersion polymer layer filled in the optical guide groove to guide transmission so that light emitted through the input plastic optical fiber is dispersed and distributed to the output plastic optical fibers.

The base block is preferably formed of a transparent acrylic material.

In addition, the refractive index of the dispersion polymer layer is applied to 1.55 to 1.57.

More preferably, a plurality of the input plastic optical fibers are arranged in a horizontal direction and a vertical direction with respect to the base block.

The distance between the input plastic optical fiber and the output plastic optical fiber is preferably 1.8cm to 2.4cm.

According to the plastic optical fiber coupler according to the present invention, it is easy to manufacture, the structure is simple, and the expansion of the input / output channel provides an advantage.

1 is a perspective view showing a single-layer 4x4 plastic optical fiber coupler according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating a state in which a dispersed polymer layer is filled in an optical guide groove of the plastic optical fiber coupler of FIG. 1;
3 is a perspective view illustrating a multilayer 4 × 4 plastic optical fiber coupler according to a second embodiment of the present invention;
4 is a perspective view illustrating a 1 × 2 plastic optical fiber coupler according to a third embodiment of the present invention;
5 is a perspective view illustrating a 1 × 4 plastic optical fiber coupler according to a fourth embodiment of the present invention;
6 and 7 show the results of measuring the cross-sectional distribution of light beams at different distances when light is emitted through the first input plastic optical fiber and when the light is emitted through the second input plastic optical fiber for the coupler of FIG. 1. Is the drawing shown,
8 is a graph illustrating a result of measuring coupling efficiency of four output plastic optical fibers according to a separation distance from a dispersion polymer layer when light is emitted through the first input plastic optical fiber of FIG. 1,
FIG. 9 is a graph illustrating a result of measuring coupling efficiency of four output plastic optical fibers according to a separation distance from a dispersed polymer layer when light is emitted through the second input plastic optical fiber of FIG. 1,
10 and 11 are graphs showing the results of measuring the beam pattern and the coupling efficiency of each coupler distance in the dispersed polymer layer with respect to the coupler of FIG.
12 to 14 is a graph showing a result of measuring the coupling efficiency of the coupler manufactured by the structure of Figure 1 by the separation distance,
15 to 17 is a graph showing the results of measuring the coupling efficiency of the coupler manufactured by the structure of Figure 3 by the separation distance.

Hereinafter, a plastic optical fiber coupler according to a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a perspective view illustrating a horizontal 4 × 4 plastic optical fiber coupler according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a state where a dispersed polymer layer is filled in an optical guide groove of the plastic optical fiber coupler of FIG. 1. to be.

1 and 2, the plastic optical fiber coupler 100 includes a base block 110, an input channel unit 120, an output channel unit 130, and a dispersed polymer layer 140.

The base block 110 is formed of a transparent synthetic resin material in the form of a rectangular parallelepiped, and an optical guide groove 112 for guiding light along a longitudinal direction is formed on an upper surface thereof.

Here, the optical guide grooves 112 formed in the base block 110 are accommodated in a state in which end portions of the input plastic optical fibers 121 to 124 described later are aligned with each other, and the front ends of the output plastic optical fibers 131 to 134. While some are aligned and received in close contact with each other, the light is selectively emitted from the input plastic optical fibers 121 to 124 and uniformly distributed through the dispersion polymer layer 140 described below as the output plastic optical fibers 131 to 134. It can be formed so that it can be distributedly distributed.

That is, the optical guide groove 112 formed in the base block 110 is a region in which the input plastic optical fibers 121 to 124 are mounted so that the input plastic optical fibers 121 to 124 to which the input plastic optical fibers 121 to 124 are applied are aligned to be in close contact with each other. A predetermined length is formed in one width, and the area in which the output plastic optical fibers 131 to 124 are mounted is formed to have a predetermined length in a second width that is required to be aligned so that the output plastic optical fibers 131 to 134 are applied to each other. The separation region between the ends of the plastic optical fibers 121 to 124 and the distal ends of the output plastic optical fibers 131 to 134 may be formed in a form of linearly connecting the edges of the first width and the second width.

The base block 110 is preferably formed of a transparent acrylic material.

In the input channel unit 120, four input plastic optical fibers 121 to 124 are aligned side by side in a single layer such that a predetermined portion enters the optical guide groove 112 at one end of the base block 110.

The output channel unit 130 has four output plastic optical fibers 131 to 124 so that a predetermined portion of the front end enters the optical guide groove 112 at the other end of the base block 110 and is spaced apart from the ends of the input plastic optical fibers 121 to 124. 134 are aligned side by side in a fault.

The distance between the input plastic optical fibers 121 to 124 and the output plastic optical fibers 131 to 134 is preferably applied to 1.8 cm to 2.4 cm.

The dispersion polymer layer 140 is filled in the light guide groove 112 so that the light emitted through any one of the input plastic optical fibers 121 to 124 is dispersed and distributed evenly to the output plastic optical fibers 131 to 134.

Here, the refractive index of the dispersion polymer layer 140 is higher than the refractive index of the base block made of acrylic so that the light to be guided can be totally reflected at the interface with the base block 110 formed of acrylic material.

The dispersion polymer layer 140 is preferably formed of a polymer having a transparent refractive index of 1.55 to 1.57.

In this structure, the light rays emitted from the input plastic optical fibers 121 to 124 of any one of the input plastic optical fibers 121 to 124 are guided through the dispersion polymer layer 140, and the light rays are guided through different paths in the process of being guided. Diffused, and some light rays are uniformly distributed in the cross-sectional direction of the light guide groove 112 while being reflected at the interface with the base block 110 and then evenly distributed to the output plastic optical fibers 131 to 134. Is sent.

On the other hand, unlike the illustrated example, as shown in Figure 3, the plastic optical fiber coupler 200 is input plastic optical fibers (221 to 224) in the optical guide groove 212 formed in the base block 210 for the 4 × 4 channel structure ) Are horizontally arranged in two layers in two vertically, and the output plastic optical fibers (231 to 234) can also be formed in a structure in which two are arranged in two layers in two vertically horizontally. Of course.

Meanwhile, the number of channels of the input channel unit 120 and the number of channels of the output channel unit 130 may be appropriately applied. For example, in the case of the 1 × 2 channel structure, as shown in FIG. 4, the plastic optical fiber coupler 300 is formed in the form of mounting through the optical guide groove 312 formed in the base block 310 to align one input plastic optical fiber 321 and two output plastic optical fibers 331, 332 That's it.

In addition, in the case of a 1 × 4 channel structure, as shown in FIG. 5, the plastic optical fiber coupler 400 may have a base to align one input plastic optical fiber 421 and four output plastic optical fibers 431 to 434. The light guide groove 412 formed in the block 410 may be formed in the form of mounting.

Meanwhile, the 1 × 2 channel structure or the 1 × 4 channel structure may be formed in the multilayer method described above with reference to FIG. 3.

In addition, the dispersion polymer layer 140 described with reference to FIG. 2 is formed in the light guide grooves 212, 312 and 412 described with reference to FIGS. 3 to 5.

Hereinafter, the performance of the plastic optical fiber coupler will be described.

First, the optical loss is caused by Fresnel reflection in the input plastic optical fiber and the output plastic optical fiber and the dispersion polymer layer 140, absorption in the dispersion polymer layer 140, light beam leakage at the external interface and scattering due to surface roughness. Can be generated by Fresnel reflection can be minimized by matching the refractive index of the core material of the plastic optical fiber and the dispersion polymer layer 140. The absorption loss caused by the dispersing polymer layer 140 is inevitable due to the inherent property of the material, and in order to suppress scattering of the light beam, surface treatment may be performed to lower the roughness of the surface of the optical guide groove.

On the other hand, the leakage loss in the dispersed polymer layer 140 and the plastic optical fiber can be easily calculated assuming that the light beam is uniformly distributed in the dispersed polymer layer 140, and assuming a uniform distribution of the light beam, 28 % Leaks from the core of the plastic optical fiber.

The optical power flatness of the output plastic optical fiber is an important parameter in determining the performance of the plastic coupler, and the performance is described below through manufacturing and experimentation.

<Production example>

First, two types of couplers of FIGS. 1 and 3 are manufactured, and for convenience of description, the structure of FIG. 1 will be described as an A coupler 100 and the structure of FIG. 3 will be described as a B coupler 200.

An acrylic base block 110 and 210 having a refractive index of 1.49 and an epoxy having a refractive index of 1.56 and being cured by ultraviolet rays are prepared for use as the dispersion polymer layer 140 and have the structure shown in FIGS. 1 and 3. Produced.

In more detail, the rectangular optical guide grooves 112 and 212 were formed in the base blocks 110 and 210 made of acrylic material, and the surfaces thereof were polished. Here, the optical guide groove 112 of the A coupler 100 has a width of 4.0 mm and a height of 1.0 mm, and the optical guide groove 212 of the B coupler 200 has a width of 2.0 mm and a height of 2.0 mm. It was.

In addition, the refractive indexes of the core and the clad of the applied plastic optical fiber were 1.49 and 1.41, respectively, and the diameters of the core and the clad were 980 mm and 1000 mm.

The ends of the plastic optical fibers 121 to 124 (211 to 214) (131 to 134) (231 to 234) are polished and fixed to the optical guide grooves 112 and 212 of the base blocks 110 and 210. . Next, the polymer was filled in the light guide grooves 112 and 212 to form the dispersed polymer layer 140. Here, a plurality of samples were produced in which the separation distance L between the input channel unit 120 and the output channel unit 130 is different from each other.

Fresnel reflections in the applied input plastic optical fibers 121-124 (211-214) and the dispersion polymer layer 140 were measured to be 0.5% or less.

In order to measure the performance of the fabricated couplers 100 and 200, the distance between the input channel unit 120 and the output channel unit 130 in the dispersed polymer layer 140 using a light emitting diode having a center wavelength of 635 nm as a light source. The light pattern in the cross section was calculated for each position where the distance L was different from each other, and the first position of the A coupler 100 at the initial position corresponding to the end of the input plastic optical fiber and 2 mm, 6 mm, and 18 mm from the initial position. 6 and 7 show cross-sectional distributions of light beams when light is emitted through the input plastic optical fiber 121 and when light is emitted through the second input plastic optical fiber 122. 6 and 7, as the distance from the ends of the input plastic optical fibers 121 and 122 increases, the light beams are widely distributed and distributed in the dispersed polymer layer 140.

8 is a graph showing the results of measuring the coupling efficiency of the four output plastic optical fibers (131 to 134) according to the separation distance with the dispersion polymer layer 140 when the light is emitted through the first input plastic optical fiber 121 9 shows the result of measuring the coupling efficiency of the four output plastic optical fibers 131 to 134 according to the separation distance from the dispersion polymer layer 140 when the light is emitted through the second input plastic optical fiber 122. The graph shown.

8 and 9, the longer the length of the dispersed polymer layer 140, the flat coupling efficiency is provided for each of the four output plastic optical fibers 131 to 134.

10 and 11 are graphs showing the results of measuring the beam pattern and the coupling efficiency of the B coupler 200 according to the separation distance in the dispersed polymer layer.

As can be seen from FIGS. 10 and 11, the B coupler 200 may be uniformly diffused even if the distance of the dispersed polymer layer 140 is shorter than that of the A coupler 100.

Meanwhile, in order to measure the coupling ratio of the input channel unit 120 and the output channel unit 130 of the manufactured A coupler 100, the light emitting diode having a center wavelength of 635 nm is used as a light source and separated from the dispersed polymer layer 140. 12 to 14 show the results of measuring the coupling efficiency from the light detected through the four output ports when light is input for each input port for samples having a distance L of 1.0, 1.4, and 1.8 cm, respectively. It is.

Also, the sample B coupler 200 manufactured under the same conditions, that is, a sample having a separation distance L of 1.0, 1.4, and 1.8 cm from the dispersed polymer layer 140 using light emitting diodes having a center wavelength of 635 nm as a light source, respectively. 15 to 17 show the results of measuring the coupling efficiency from the light detected through the four output ports when light is input for each input port.

As can be seen from the experimental results, the uniformity of dispersion of the output ports increases as the distance between the input channel unit 120 and the output channel unit 130 in the dispersion polymer layer 140 increases. It can be seen. In addition, it can be seen that the dispersion uniformity of the B coupler 200 is higher than that of the A coupler 100 for the same separation distance L. In addition, the B coupler 100 provided a coupling efficiency of less than 2.5 dB, and the excess loss was 2.0 to 2.8 dB.

However, since the excess loss increases as the length of the dispersed polymer layer 140 increases, the length of the dispersed polymer layer is preferably applied to 1.8 to 2.2 cm.

110, 210, 310, and 410: base block 120: input channel portion
130: output channel portion 140: dispersed polymer layer

Claims (5)

Plastic fiber coupler,
A base block formed of a transparent synthetic resin material and having an optical guide groove formed thereon for guiding light along a longitudinal direction thereof;
An input channel part in which at least one input plastic optical fiber is mounted in the optical guide groove at one end of the base block;
An output channel unit having a plurality of output plastic optical fibers mounted in the optical guide groove at the other end of the base block to be spaced apart from the input plastic optical fiber;
And a dispersion polymer layer filled in the optical guide groove and guiding transmission so that the light emitted through the input plastic optical fiber is dispersed and distributed to the output plastic optical fibers. The plastic optical coupler of claim 1, wherein the base block is formed of a transparent acrylic material. The plastic optical coupler of claim 2, wherein the dispersion polymer layer has a refractive index of 1.55 to 1.57. The plastic optical coupler of claim 3, wherein a plurality of the input plastic optical fibers are arranged along a horizontal direction and a vertical direction with respect to the base block. The plastic optical coupler of claim 4, wherein a distance between the input plastic optical fiber and the output plastic optical fiber is 1.8 cm to 2.4 cm.

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