JPH02134605A - Manufacture of fiber type coupler - Google Patents

Abstract

PURPOSE:To improve the reproducibility and the yield at the time of mass- production by removing part of the jacket of a coated optical fiber partially, fusing and drawing the jacket removed part and forming a coupler part, removing the jackets of both ends, and dipping the jacket removed parts in a storing base solution and forming branch parts. CONSTITUTION:The jacket of the coated optical fiber 1 is removed partially and this jacket removed part A is fused and drawn to form the coupler part B. Then the jackets 3 of both ends of the coated optical fiber 1 are removed and the jacket removed parts C are dipped in the strong base solution to form the branch parts. Therefore, the coupler part B is easily formed at a specific branch ratio in a 1st process and the branch parts are easily formed in a 2nd process. Consequently, the reproducibility and the yield at the time of mass- production are improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a fiber coupler from an optical fiber core having a plurality of cores, and is used for communication, a total of 4PJ, etc. The present invention relates to a method of manufacturing a fiber type coupler that can be manufactured.

[Conventional technology]

Optical branching couplers are classified into three types based on their components and functions: types that use optical components, types that use optical fibers, and waveguide types. Optical fiber-based types do not require the use of optical components such as lenses and are It has advantages such as a small number of points and easy manufacturing.

Hereinafter, a method of manufacturing a conventional optical fiber splitter/coupler will be described. Conventional optical branching coupler (optical fiber type)
Manufacturing methods are broadly divided into polishing methods, etching methods, and melt tube methods. The polishing method is a method of scraping off the cladding part of an optical fiber and bringing the core parts of the optical fiber closer to each other.
The etching method is a method in which an optical fiber is permeated with a highly acidic or highly alkaline liquid, the cladding portion of the optical fiber is etched, and the optical fibers are twisted together to bring the core portions closer to each other.

Furthermore, there are two methods for fusion bonding depending on the arrangement of the two optical fibers. The first method involves removing part of the coating from two optical fibers, twisting them together, and heating and melting them to integrate them (S
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The method involves removing part of the coating from two optical fibers,
These are placed in parallel and integrated by heating and melting (Publication Patent Publication No. 6O-50142
7).

[Problem to be solved by the invention]

However, in the conventional manufacturing method, multiple optical fibers are twisted together or closely aligned in parallel, then fused and stretched, making it difficult to obtain fiber couplers with the same shape and characteristics. there were. Therefore, there is a drawback that the variation in the branching/demultiplexing state during stretching becomes large, resulting in poor yield during mass production.

Therefore, an object of the present invention is to provide a manufacturing method that is reproducible and has a high yield during mass production, thereby stabilizing the structure and characteristics of a fiber coupler.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a method for manufacturing a fiber coupler from an optical fiber coated wire having a plurality of cores, in which a part of the coating of the coated optical fiber is removed, and the coating is removed. The first step is to form a coupler part by fusing and stretching the parts, and the branch part is formed by removing the coating from both ends of the optical fiber and immersing the part from which the coating has been removed in a strong alkaline solution. The method includes a second step.

In this second step, if a hydrofluoric acid aqueous solution is used as the strong alkaline solution, the etching process can be carried out efficiently.

Further, in the second step, the coating removal portion may be coated with a coating material after branching.

[Effect]

Since the present invention is configured as described above, the coupler portion can be easily formed at a predetermined branching ratio in the first step, and the branching portion can be easily formed in the second step. can.

Therefore, fiber couplers can be manufactured with good reproducibility, and variations in shape and characteristics can be reduced.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a fiber coupler according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description will be omitted.

The explanation will be given below based on FIGS. 1 and 2. Figure 1 shows
2 is a flowchart showing a method for manufacturing a fiber coupler according to an embodiment, and FIG. 2 is a process diagram showing a process for manufacturing a fiber coupler according to an embodiment.

In step 101, part of the coating of the punched fiber core 1 is removed (FIGS. 2(a) and 2(b)).

The punched optical fiber core 1 includes a plurality of cores 1a and 1b integrated by a common rad 1a, and a coating material 1d.
(See figure (a)).

In step 102, the coated removed part A is heated with a burner 2 to fuse and stretch the coated removed part A (see FIG. 2(C)).
). In this case, the branching ratio is monitored by inputting monitor light from one end of the optical fiber 1 and detecting the optical power at the other end.

In step 103, the branching ratio is a predetermined value (for example, 50%).
determine whether it has become. If the predetermined value is not reached, fusing and stretching are continued, but when the predetermined value is reached, the stretching is stopped (
Step 104). At this stage, the coupler portion B is formed (FIG. 2(d)).

In step 105, the coating at both ends of the punched optical fiber 1 is removed (FIG. 2(e)), and both ends (coating removal section C5C) are branched (step 106). That is,
The core 1b constituting the punched optical fiber coated wire 1 is branched from other core ICs, and each core portion (core and part of the cladding) is separated (FIG. 4(f)). In this case, the core portion can be separated by immersing the coating removal portion in a strong alkaline solution such as a hydrofluoric acid aqueous solution and etching the common rad portion.

In step 107, the separated core portions are coated with a coating material 3.3 (FIG. 3(g)). for example,
The coating material can be coated by applying a thermosetting silicone resin by spraying or the like and heating it in an oven or the like.

Note that this invention is not limited to the above embodiments. For example, in this embodiment, a punched optical fiber is used as the optical fiber, but a multi-core optical fiber may also be used. Furthermore, the manufactured fiber coupler includes at least a branch/combiner and a branch/multiplexer.

Next, experimental results related to this invention will be explained. Figure 3 shows
This figure shows experimental results regarding etching treatment for optical fibers. In this experiment, 4.5 g of hydrofluoric acid and 9 g of pure water were used.
．． A punched optical fiber with a single core of 70 μm was immersed in an aqueous solution of hydrofluoric acid mixed with 0 g of hydrofluoric acid, and the time taken until the coating removal part could branch and the change in the outer diameter of the cladding part were measured.

According to this experiment, the coating removal section could be branched in about 1.5 hours. In this case, the outer diameter of each branched core portion was 38 μm, and the portion etched to the point where the coating removal portion could be separated was approximately 30 μm.

Therefore, from this experiment, in order to ultimately make the outer diameter of each core part of the punched optical fiber 125 μm,
It can be seen that it is sufficient to finish each core to approximately 155 μm in consideration of the amount of etching.

In this experiment, it was confirmed that if the outer diameter of the punched optical fiber was set to 155 μm in order to obtain a branched state with an outer diameter of 125 μm, the fiber coupler could be etched with an accuracy of 125 μm±3 μm.

〔Effect of the invention〕

Since this invention is configured as explained above,
It has good reproducibility and can improve yield during mass production.

Furthermore, it is possible to manufacture a fiber coupler with stable characteristics, and it becomes easy to produce two fiber couplers.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a method of manufacturing a fiber coupler according to an embodiment of the present invention, FIG. 2 is a process diagram showing a manufacturing process of a fiber coupler according to this embodiment, and FIG. FIG. 3 is a diagram showing experimental results regarding etching processing on fibers. 1...Punched optical fiber core wire 2...Burner 3...Coating material ASC...Coating removal part B...Coupler part Manufacturing method of fiber type coupler Figure 1

Claims (1)

[Claims] 1. A method for manufacturing a fiber coupler for manufacturing a fiber coupler from a coated optical fiber having a plurality of cores, comprising: removing a part of the coating of the coated optical fiber; The first coupler part is formed by fusing and stretching the
and a second step of forming a branch by removing the coating from both ends of the optical fiber core and immersing the removed coating in a strong alkaline solution. Method. 2. The method for manufacturing a fiber coupler according to claim 1, wherein in the second step, a hydrofluoric acid aqueous solution is used as the strong alkaline solution. 3. The method for manufacturing a fiber coupler according to claim 1, wherein in the second step, the coating removal portion is coated with a coating material after branching.