JPH1123862A - Terminator for optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make small-sized and low-cost the terminator provided to an unused end part of the optical fiber. SOLUTION: An end surface 25b is formed in a low-reflection state by cutting an end part 25a of the optical fiber 25 with a nipper while crushing it. The end surface 25b is covered with a metal-based tape 1 which is formed of aluminum and has adhesive strength on its reverse surface. At the end part 25a, a rod 2 for reinforcement is arranged adjacently having the axial direction aligned. The rod 2 and end part 25a are arranged in a heat-shrinkable tube 3 made of silicone resin and heated from outside by a heat gun, etc., to shrink, so that the end part 25a and rod 2 are coated in contact. Consequently, the constitution of the terminator 10 is simplified, so the cost is lowered. Further, the terminator 10 can be made small-sized, so it can be stored in an existing fiber tray used for an outdoor cable connection point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminator for preventing reflection and transmission of laser light at an unused end of an optical fiber.

[0002]

2. Description of the Related Art Conventionally, there is a problem that laser light is reflected on an open end face where an optical fiber is not connected to another fiber, and the reflection deteriorates transmission characteristics and increases noise and distortion. is there. Further, if the unused end is directly opened to the outside air, the laser light is radiated to the outside and is harmful to the human body. Therefore, a terminator is provided to prevent reflection and transmission of the laser light on the end face. As a method of preventing the reflection of laser light at the end face, for example, a ferrule is used, and one end is connected to the end of the optical transmission line with low reflection and low loss, and the other end hardly reflects and transmits laser light. There is known a structure having no structure (Japanese Patent Laid-Open No. Hei 4-34713).

[0003]

However, in the above-mentioned conventional method, it is necessary to mount an optical connector comprising a spring, a stopper, a plug frame, a cap and the like in order to connect the ferrule to the optical fiber. Because it is large enough compared to the diameter (usually about 10m
m), there is a problem that it is difficult to store the optical connector in the fiber tray used for the outdoor connection point of the optical fiber cable. In order to accommodate this optical connector, it is necessary to modify the design of the existing fiber tray and provide a sufficient space, and this series of operations is newly added, resulting in an increase in cost. Further, since the optical connector itself used for the terminator is expensive, there is a problem that this also leads to an increase in cost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to reduce the size of a terminator provided at an unused end of an optical fiber so that the terminator can be housed in a fiber tray. That is, the cost of the terminator is reduced.

[0005]

According to the first aspect of the present invention, the reflection of the laser light at the end face of the optical fiber is formed in a low reflection state, and the laser light is reflected at the end face. The end surface is covered by the covering member so that the radiation is not radiated from the outside. The bar-shaped reinforcing member is arranged adjacent to the end with its axial direction aligned with the axial direction of the end.
The reinforcing member only needs to have enough strength to prevent bending of the end portion, and the outer diameter can be sufficiently reduced. The end portion and the reinforcing member are arranged inside the tubular heat-shrinkable tube, and are heated from the outside, whereby the heat-shrinkable tube shrinks and the end portion and the reinforcing member are tightly covered. By providing this terminator at the unused end of the optical fiber, reflection and transmission of light at the end face can be prevented.
Further, since the heat-shrinkable tube covers the reinforcing member and the end portion in close contact with each other, it is possible to have a sufficient bending strength. In addition, since the terminator includes the covering member, the reinforcing member, and the heat-shrinkable tube, a simple structure can be achieved, and the cost of the terminator can be reduced. Further, since the terminator can have an outer diameter sufficiently smaller than the outer diameter of a conventional connector, it can be housed in an existing fiber tray.

According to the second aspect of the present invention, the end face of the optical fiber is formed by being cut while the end portion of the optical fiber is crushed by a cutting tool such as a nipper. Thereby, since the end face can be formed using a nipper or the like, the end face can be formed by a simple method. Further, since the end face formed in this manner is not orthogonal to the axial direction of the optical fiber, the amount of reflection of laser light on the end face can be reduced. Also, by checking the reflection state of the laser light using a return loss tester, etc., by cutting the optical fiber,
It is possible to form an end face having a smaller amount of laser light reflection.

According to the third aspect of the present invention, by using a silicon-based resin, a fluorine-based resin, polyolefin or polyvinyl chloride as the heat-shrinkable tube, good heat-shrinkability can be obtained, and the reinforcing member and the light The end of the fiber can be better adhered and covered. Further, since the heat-shrinkable tube made of these resins is commercially available, it is easy to obtain and the cost can be further reduced.

According to the fourth aspect of the present invention, by using a tape made of a metal such as aluminum or copper as the covering member, the operation of covering the end face with the covering member can be performed efficiently. Further, since this metal tape is commercially available, it is easy to obtain, and the cost can be further reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on specific embodiments. FIG. 1 is a schematic diagram showing the configuration of the terminator 10. The terminator 10 is provided at an unused end 25 a of the optical fiber 25. The optical fiber 25 has a core diameter of 10 μm, a fiber diameter of 125 μm, and an outer diameter of 0.9 mm. The end portion 25a is formed such that the reflection of the laser beam on the end surface 25b is in a low reflection state. The end face 25b can be formed by cutting the optical fiber 25 while crushing it using a nipper. Optical fiber 25
Is cut at a right angle to the axial direction, the amount of reflection on the end face 25b increases.
5b is cut while crushing the end face 25a.
Are formed obliquely to the axial direction, and the amount of reflection of the laser light on the end face 25b can be reduced. In order to further suppress the reflection of the laser light on the end face 25b, for example, it is possible to form the end face 25b with the least reflection while checking the reflection state of the laser light using a return loss tester.

The terminator 10 includes a metal tape (covering member) 1 for covering an end face 25b of an unused end 25a of the optical fiber 25, and a reinforcing tape disposed adjacent to the end 25a in the axial direction. It comprises a rod (reinforcing member) 2 and a heat-shrinkable tube 3 that covers the end 25a and the rod 2 in close contact. The tape 1 is made of aluminum and has an adhesive property on the back surface. Rod 2 is made of steel and has a diameter of about 1.5mm
It is a commercial product with a length of about 57 mm. The tube 3 is made of a silicon-based resin, contracts when heated from the outside, and covers the end portion 25a and the rod 2 in close contact.

Next, a method of forming the terminator 10 will be described below. First, the end portion 25 of the optical fiber 25 is checked while confirming the reflection amount of the laser light using the return loss tester.
a is cut using a nipper to form an end face 25b in a state where the amount of reflection is the smallest. Then, the end face 25b is covered with the tape 1, and the tape 1 is wound around the outer periphery of the end 25a. Next, the axial direction of the rod 2 is aligned with the axial direction of the end 25a, and the rod 2 is disposed adjacent to the end 25a. And
The end 25a and the rod 2 are arranged in the tube 3, and the tube 3 is placed from the outside using a heat gun, an electric furnace, a drier or the like.
Heat. By this heating, the tube 3 shrinks, and the rod 2 and the end portion 25a are tightly covered. Thus, a terminator 10 having an outer diameter of about 3 mm is formed.

By configuring the terminator 10 as described above,
The reflection and transmission of the laser beam on the end face 25b can be prevented. Further, since the end portion 25a can be reinforced by using the rod 2, the end portion 25a has sufficient bending strength. or,
Tape 1, rod 2, and tube 3 that constitute the terminator 10
Are commercially available, so that they can be easily obtained and the cost of the terminator 10 can be reduced.

FIG. 2 is a block diagram showing an example of use of the terminator 10. One end of each of the optical fibers 21 and 22 is connected to an optical device (not shown), and the other end is fused at a connection point 26. Also, the optical fiber 23
Is connected to an optical device (not shown), and the other end is
It is connected to the distributor 20. An optical fiber 2 having one end connected to an optical device (not shown)
The other end of the optical fiber 25 and the other end of the optical fiber 25 provided with the terminator 10 at one end are connected. The optical fiber 25 is fused at a connection point 27. Since the outer diameter of the terminator 10 is about 3 mm as described above, it can be made much smaller (about 1/10 in area ratio) than the conventional connector type terminator.
Can be stored in a gap in the fiber tray 30 as shown in FIG. Accordingly, it is not necessary to provide a special space in the fiber tray 30 for storing the terminator 10, and the terminator 10 can be stored in the existing fiber tray 30.

In the above embodiment, the tape 1 made of aluminum is used as the covering member, but other commercially available metal tapes such as copper may be used. Further, the covering member is not limited to a commercially available product, and may be made of a material other than metal as long as it can prevent light transmission. or,
Although the bar 2 made of commercially available steel was used as the reinforcing member, the bar 2 is not limited to a commercially available product, and may be made of another material as long as the end portion 25a can be reinforced.
Further, although the tube 3 made of a silicon-based resin is used, other materials such as a fluorine-based resin, polyolefin, or polyvinyl chloride may be used as long as heat shrinkage is possible. Although the end face 25b is formed using a nipper, the optical fiber 25
May be used as long as the end face 25b can be formed obliquely with respect to the axial direction. Also, the end face 25b was cut into a crushed shape,
The end face 25b may be formed in another shape as long as it can prevent light reflection. For example, the end face 25b may be formed obliquely at a predetermined angle with respect to the axial direction of the optical fiber 25.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a terminator according to a specific embodiment of the present invention.

FIG. 2 is a block diagram showing a usage example of a terminator according to a specific embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tape 2 Reinforcing rod 3 Heat shrinkable tube 10 Terminator 20 Optical branching / distributor 21-25 Optical fiber 25a Optical fiber end 25b Optical fiber end 26, 27 Fusion splicing point 30 Fiber tray

Claims (4)

[Claims] 1. An end portion of an optical fiber in which reflection of laser light on an end face is formed in a low reflection state, a covering member covering the end face so that the laser light is not emitted from the end face to the outside, and a rod-shaped member. And a reinforcing member arranged adjacent to the end with its axial direction aligned with the axial direction of the end, forming a cylindrical shape, the end and the reinforcing member being disposed inside, An optical fiber terminator, comprising: a heat-shrinkable tube that shrinks by being heated from the outside and tightly covers the end portion and the reinforcing member. 2. The optical fiber terminator according to claim 1, wherein the end face is formed by being cut while being crushed by a cutting tool such as a nipper. 3. The optical fiber terminator according to claim 1, wherein the heat-shrinkable tube is made of silicon-based resin, fluorine-based resin, polyolefin, or polyvinyl chloride. 4. The optical fiber terminator according to claim 1, wherein the covering member is a tape made of a metal such as aluminum or copper.