JPH028806A - Optical distributor - Google Patents

Abstract

PURPOSE:To distribute light uniformly and to facilitate the manufacture by forming a mixing member in a hollow conic shape and joining an incidence optical fiber with the small-diameter side end surface and plural projection optical fibers with the large-diameter side end surface. CONSTITUTION:The small-diameter end surface 13b of the mixing member which is formed in the hollow conic shape and has an internal space 13a is joined with the end surface center of the incidence optical fiber 10 and the large-diameter end surface 13c is joined with end surfaces of the respective projection optical fibers 11 by heat fusion. Single-mode emitting light emitted from the incidence optical fiber 10 is not propagated in the internal space 13a of the mixing member 13, but diffused conically along the mixing member 13 to enter the respective emitting optical fibers 11, so the light can be distributed equally to the single-mode emitting optical fibers 11 and the manufacture of the optical distributor is facilitated.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an optical splitter for distributing light between single mode optical fibers.

(Technical background of the invention and its problems) Conventionally, the ends of a plurality of multimode output optical fibers are integrally heat-sealed to form a tapered fused portion, and the tip of the tapered fused portion is 2. Description of the Related Art An optical distributor is known which has a structure in which a multi-mode input optical fiber and an eyeglass are thermally fused and the incident light is distributed to each output optical fiber via a tapered thermally fused portion.

Therefore, the applicant has developed a fifth optical fiber using a single mode optical fiber.
The optical distributor shown in the figure was manufactured. That is, in FIG.
Reference numeral 1 indicates a single-mode input optical fiber, and the input optical fiber 1 consists of a core 1a of 10 ILm and a cladding 1b provided thereon with an outer diameter of 125 μm. The tip of a tapered fused portion 2 is heat fused to the end surface of the core 1a. This tapered fused portion 2 is formed by integrally heat-sealing the end side surfaces of a plurality of single mode output optical fibers 3 and applying a tensile force to the fused portion. Each output optical fiber 3 also has a core of 10 μm.
It consists of a cladding of 125 μm.

However, in an optical splitter with such a structure, the input optical fiber 1
It was impossible to evenly distribute the output light from the output optical fibers 3 to each output optical fiber 3. That is, since the single-mode input optical fiber 1 propagates only single-mode light, the output light from the fiber 1 propagates through the center of the tapered fused portion 2, and most of the output light is located at the center. It is distributed to fiber 3. Moreover, the core 1a of the input optical fiber 1 is 10
Since it has a very small diameter of μm, it is difficult to form the tip of the tapered welded part 2 to a small diameter corresponding to the core 1a and to thermally fuse the optical axis so that it coincides with the core 1a. However, manufacturing the optical distributor requires a great deal of time and effort, and also requires a skilled person.

FIG. 6 shows a light distributor using a mixing rod. That is, in this optical distributor, a mixing rod 4 is arranged between a single mode input optical fiber 1 and a plurality of single mode output optical fibers 3. This mixing rod 4 is formed into a conical shape, and the end face on the large diameter side is joined to each output optical fiber 3. The optical distributor having such a structure is easy to manufacture because it is sufficient to join the small-diameter side end surface of the mixing rod 4 to the end surface of the input optical fiber 1. However, even if the mixing rod 4 is used in this way, as described above, the output light from the input optical fiber 1 only propagates through the center of the mixing rod 4, so it is still distributed to the output optical fiber 3 located at the center. Put it away.

As shown in FIG. 7, one end of a mixing rod 5 having approximately the same outer diameter is joined to the end surface of the core 1a of the input optical fiber l, and the other end of the mixing rod 5 is connected to a tapered fused portion 2.
Another light distributor was fabricated by joining it to the tip of the . However, this optical distributor is also difficult to manufacture, and the light is similarly distributed to the output optical fiber 3 located at the center. Further, since the mixing rod 5 having a small diameter is used, there is another drawback in that the mechanical strength is poor.

(Object of the Invention) An object of the present invention is to provide an optical distributor that can evenly distribute light even when using a single mode optical fiber and has a structure that is easy to manufacture.

(Summary of the Invention) The present invention is characterized in that a hollow conical mixing member is disposed between a single mode input optical fiber and a plurality of single mode output optical fibers arranged along the circumference.

Further, in another invention, a plurality of single mode optical fibers disposed along the circumference and a plurality of other single mode optical fibers similarly disposed along the circumference are arranged from the center to both sides. It is characterized by a mixing rod that gradually expands in diameter and is hollow.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view of the optical distributor according to the present invention, and FIG.
It is a sectional view taken along the line AA in the figure.

In these figures, 10 indicates a single-mode input optical fiber, and the input optical fiber 10 has a diameter of OLJ,
It consists of a core 10a with a diameter of m and a clad 10b with an outer diameter of 125 μm. A plurality of single mode output optical fibers 1 are opposed to the input optical fiber 10. These output optical fibers 11 are closely arranged along the circumference and have a diameter of 1
Core 11a with a diameter of 0 μm and cladding 11 with an outer diameter of 125 μm
It consists of b. A plurality of dummy rods 12 are inserted inside these output optical fibers 11. These dummy rods 12 are inserted to arrange each output optical fiber 11 along the circumference, and are made of small diameter glass rods.

A mixing member 13 is arranged between the input optical fiber IQ and the output optical fiber 11. As shown in FIGS. 1 and 3, the mixing member 13 is formed into a hollow conical shape and has an internal space 13a. The small diameter side end surface 13b of the mixing member 13 is joined to the center of the end surface of the input optical fiber 10 by heat fusion, and the large diameter side end surface 13c is joined to the end surface of each output optical fiber 11 by heat fusion.

In the optical splitter having the above structure, when the single mode output light is output from the single mode input optical fiber 10 and enters the small diameter portion of the mixing member 13, 1;
It diffuses in the mixing member 13 in a conical shape. That is, the air existing in the internal space 13a of the mixing member 13 acts on the mixing member 13 as a cladding with a small refractive index. Therefore, the single mode output light does not propagate through the center (inner space 13a) of the mixing member 13, but is diffused conically along the mixing member and enters each output optical fiber 11. Therefore, single mode output light can be evenly distributed to each single mode output optical fiber 11.

FIG. 4 is a front view of a light distributor according to another embodiment of the invention. In FIG. 4, reference numeral 14 indicates a plurality of single-mode optical fibers at one end, and these optical fibers 14 are arranged along the circumference via dummy rods (not shown) in the same manner as described above. . Moreover, a plurality of other single mode optical fibers 15 are disposed on the other end side facing these optical fibers 14. These optical fibers 15 are also arranged along the circumference via dummy rods (not shown). A mixing rod 16 is arranged between the optical fiber 14 and the optical fiber 15. The mixing rod 16 has a small diameter in the center and has enlarged diameter parts 16A and 16B that gradually increase in diameter toward both sides. Each enlarged diameter portion 16A, 16B is formed hollow, and has an internal space 16a,
16b. The end surface of one enlarged diameter section 16A is joined to the end surface of each optical fiber 14 by heat fusion, and the end surface of the other enlarged diameter section 16B is joined to the end surface of each optical fiber 15 by heat fusion. There is. Therefore, a star-coupler type optical distributor is obtained.

In the optical distributor having the above structure, the internal spaces 16a, 1 of the enlarged diameter portions 16A, 16B of the mixing rod 16 are
The air present in 6b acts as a cladding for the rod 16. Therefore, one optical fiber 14 on one end side
The single-mode light emitted from the mixing rod 16 propagates through the enlarged diameter section 16A of the mixing rod 16 toward the center of the rod 16, and enters the other enlarged diameter section 16B from the center. Therefore, the light is diffused into a conical shape at the enlarged diameter portion 16B and is evenly distributed to the plurality of optical fibers 15 on the other end side.

By the way, the mixing rod 16 shown in FIG. 4 is manufactured as follows. That is, a hollow cylindrical glass rod is prepared, and a tensile force is applied to both ends while heating the central portion of the glass rod, thereby obtaining a mixing rod having enlarged diameter portions on both sides.

On the other hand, the mixing member 13 shown in FIG. 1 can be easily obtained by cutting the center of the mixing rod 16.

Therefore, the star coupler type optical distributor shown in FIG. 4 can be manufactured by simply joining both end faces of the mixing rod 16 to the end faces of each optical fiber 14, 15.

In addition, both ends of the mixing member 13 are connected to the input optical fiber 10.
The unidirectional optical distributor shown in FIG. 1 can be manufactured by simply joining the end face of each output optical fiber 11 to the end face of each output optical fiber 11.

(Effects of the Invention) As explained above, according to the present invention, a hollow conical mixing member is disposed between a single mode input optical fiber and a plurality of single mode output optical fibers arranged along the circumference. Therefore, the single mode output light from the input optical fiber can be equally distributed to each output optical fiber.

In addition, a mixing rod whose diameter gradually increases from the center toward both sides and is hollow is arranged between the plurality of single-mode optical fibers and the plurality of other single-mode optical fibers, so that Emitted light of one mode can be evenly distributed in both directions.

Furthermore, when a mixing rod or a mixing member is used in this way, there is no need to form a tapered fused portion at the end of the optical fiber, and there is no need to align the optical axes and optically bond, so the optical splitter The production becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a front view of the optical distributor according to the present invention, and FIG.
3 is a perspective view of a mixing member according to the present invention, FIG. 4 is a front view of a light distributor according to another invention, and FIGS. 5 to 7 are a single mode light FIG. 3 is a front view showing an example in which an optical distributor of a conventional structure is applied to a fiber. i o-------4 human-emitting optical fiber, 11--1-
-----Emission optical fiber, 12---------Dummy rod, 13------Mixing member, 14, 1 5
--- Optical fiber (single mode) 16 ---
-----Mixing rod, 16A, 16B--4 enlarged diameter part. Figure 5 Figure 6 Figure 7 (1 other person) 10 - - 11 - - - Lambda 9 fibers + 1 - - -
---4 Output optical fiber 14.15--1--Optical fiber (/ngle mode) +6-----Mixisi rod +6A, 168--4 Radial section 48 Fig. 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A single-mode input optical fiber, a plurality of single-mode output optical fibers arranged along the circumference, and a single-mode output optical fiber arranged between the input optical fiber and the output optical fiber. In the optical distributor, the mixing member is formed into a hollow conical shape, a small diameter end face is joined to the input optical fiber, and a large diameter end face is joined to the plurality of output optical fibers. An optical distributor characterized by: 2. Optical distribution comprising a mixing rod arranged between a plurality of single mode optical fibers arranged along the circumference and a plurality of other single mode optical fibers arranged along the circumference. 1. An optical distributor characterized in that the mixing rod has a diameter gradually increasing from the center toward both sides, is hollow, and has both end surfaces joined to the optical fiber.