JPH08201645A - Multi-branch optical fiber coupler - Google Patents

Abstract

(57) [Summary] (Modified) [Object] The present invention aims to provide a multi-branching optical fiber coupler manufactured by a small number of couplers. A multi-branch optical fiber coupler of the present invention is characterized by being formed into a tree by combining a 1-input 2-output optical fiber coupler and a 1-input 3-output optical fiber coupler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-branch optical fiber coupler, and more particularly to a multi-branch optical fiber coupler manufactured by using a small number of optical fiber couplers.

[0002]

2. Description of the Related Art An optical fiber coupler is a device incorporated in an optical communication system, which couples or splits optical signals with each other, or multiplexes or splits optical signals with different wavelengths. is there. However, in this optical communication system, a multi-branch optical fiber coupler is commonly used for transmitting a lot of information, and this multi-branch optical fiber coupler is conventionally used as a 1-input 2-output optical fiber coupler (hereinafter referred to as 1 × 2 branch). It is manufactured by forming a tree by fusion-splicing a number of couplers.

[0003]

However, regarding the manufacture of this multi-branch coupler, it is necessary to make 15 1-branch couplers.
Since the × 2 branch coupler is required, the price and size of the tree-branched multi-branch coupler are determined by the number of couplers to be mounted, and therefore, they are mounted for this low cost and miniaturization. It is necessary to reduce the number of couplers.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a multi-branch optical fiber coupler which solves the above problems.
This is characterized in that a multi-branch optical fiber coupler is formed into a tree by combining a 1-input 2-output optical fiber coupler and a 1-input 3-output optical fiber coupler.

That is, the inventors of the present invention have conducted various studies to develop a method for making a multi-branching coupler inexpensive and miniaturizing the multi-branching coupler.
When the × 2 branch coupler is combined with a 1 × 2 branch coupler and a 1-input / 3-output optical fiber coupler (hereinafter abbreviated as 1 × 3 branch coupler), the number of couplers for manufacturing a multi-branch coupler is reduced. So you can lower costs,
It has been found that miniaturization is possible, and according to this, the number of coupler connection points is reduced, so connection loss is reduced, and since the number of couplers is also reduced, the insertion loss of the obtained multi-branching coupler is also small and stability is improved. It was confirmed that the present invention was completed.

The multi-branch optical fiber coupler of the present invention is a tree formed by combining the 1 × 2 branch coupler and the 1 × 3 branch coupler as described above, and this 1 × 3 branch coupler has three branches. It may be made by aligning one ends of the optical fibers in parallel, removing the coating, heating and fusing them together, and cutting the fused parts. This is combined with a 1 × 2 branch coupler. And the advantage of being able to reduce the number of couplers used in the production of multi-branch couplers.

[0007]

Operation: That is, the multi-branch coupler is 1 × by the conventional method.
When only two-branch couplers are manufactured, three couplers are used in a four-branch coupler as shown in FIG. 2A, and seven couplers are used in an eight-branch coupler as shown in FIG. 2B. As shown in FIG. 2 (c), the 16-branch coupler requires 15 couplers, respectively. If the 1 × 2-branch coupler and the 1 × 3-branch coupler are combined according to the present invention, FIG. As shown in Fig. 3, three 6-branch couplers,
As shown in (b), four in the 9-branch coupler,
As shown in (c), even with an 18-branch coupler, it is only necessary to use 9 couplers, so the number of couplers for manufacturing this multi-branch coupler can be greatly reduced. Connection point of coupler (indicated by X in Figures 1 and 2)
And the insertion loss and the connection loss are reduced, which provides an advantage that the stability is also increased.

Next, examples and comparative examples of the present invention will be described. Example, Comparative Example Each branch pipe size of the coupler is 45 mm in length and 2.5 mm in diameter.
An 18-branch optical fiber coupler was manufactured by tree-forming as shown in Fig. 1 (c) using one × 2 branch coupler and eight 1 × 3 branch couplers. It has a maximum insertion loss of 13.34dB,
The minimum was 12.54 dB and the average was 12.95 dB.
However, when a 16-branch optical fiber coupler was manufactured using only this 1 × 2 branch coupler for comparison, this requires 15 couplers as shown in FIG. 2 (c),
This was mounted in a housing with internal dimensions of 90 x 95 mm.

[0009]

The multi-branch optical fiber coupler of the present invention is 1 ×
Since the two-branch coupler and the 1 × 3 branch coupler are combined to form a tree, the number of couplers used for manufacturing the multi-branch optical fiber coupler can be significantly reduced, and thus the target multi-branch optical fiber can be obtained. The fiber coupler can be obtained at a low cost, and naturally, the number of coupler connections is reduced and the connection loss is also reduced, so that the stability is increased, which is an advantage.

[Brief description of drawings]

FIG. 1 shows a multi-branching optical fiber coupler of the present invention, in which (a) is a 6-branch coupler, (b) is a 9-branch coupler,
(C) is a plan view of the 18-branch coupler.

2 shows a multi-branch optical fiber coupler of a comparative example, (a) is a 4-branch coupler, (b) is an 8-branch coupler, FIG.
(C) is a plan view of the 16-branch coupler.

Claims (1)

[Claims] 1. A multi-branching optical fiber coupler, which is made into a tree by combining a 1-input 2-output optical fiber coupler and a 1-input 3-output optical fiber coupler.