JPS6114613A - Light incident device on optical fiber - Google Patents

Abstract

PURPOSE:To wind and install easily an optical fiber by winding the optical fiber to plural winding members arranged so that the curvature increases successively, providing a light source on its side face, and making light incident on the inside of the optical fiber from the side face of the optical fiber. CONSTITUTION:A titled device is constituted of a member 8 for winding an optical fiber, and a light source 7 placed on its side face. The winding member 8 is cylinrical, plural pieces are arranged so that the curvature of the outside periphery increases successively, an optical fiber 1 of an incident side is wound successively from the winding member whose curvature is small to the member whose curvature is large, and light is irradiated from both its sides by the light source 7. As for the optical fiber 1, plural parts are bent up to a range exceeding a critical angle of transmission light with respect to the light of the light source 7, therefore, in that part, the irradiated light is made incident on the optical fiber 1, and the light which has been made incident once is confined in the optical fiber 1 and transmitted completely.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a light input device for inputting light into one optical fiber in order to align the core axis, that is, core alignment, when connecting optical fibers. be.

B. Conventional optical fibers, especially single mode optical fibers, have very thin cores, and it is not possible to achieve sufficient alignment simply by mechanically aligning the axes of the optical fibers on both sides. Therefore, conventionally, as shown in Figures 4 and 5, the input side optical fiber (1)
Connect the end of the optical fiber (6) on the transmission side to the connection point (3)
light is input from the light source (2) to one end of the input side, and from the optical fiber 1 to the optical fiber (6) on the transmitted side.
) The amount of light incident and transmitted is measured, and the optical fibers on both sides are aligned and connected so that the amount of light is maximized. To measure the amount of light incident and transmitted to the optical fiber (6), as shown in Figure 4, the optical fiber (6) is bent near the connection point and a device (4) is used to receive the leaked light from the side of the optical fiber. Alternatively, as shown in FIG. 5, there is a method in which the cladding light of an optical fiber is guided and received from the side using a glass rod (5).

C1 Problems and Objectives that the Invention Tries to Solve However, in the conventional method described above, all light enters the optical fiber (1) on the input side from the end face, as shown in FIGS. 4 and 5. . Therefore, as shown in FIGS. 4 and 5, when connecting single mode optical fibers, the optical input side (including the light source) must be located separately from the connection location. Optical fiber (1
) The end face location (4) and the connection location (to), such as a manhole, are far apart, and the connection work fζ
Placing people and equipment at two locations is very problematic from the viewpoint of workability, economy, etc., and is a drawback of the conventional method.

Therefore, it has been desired to realize a method of inputting light into the optical fiber (1) on the input side at the connection location, that is, near the connection point.

In view of the current situation, the present invention is a device in which light enters from the side of the optical fiber near the connection point, and is aimed at solving the drawbacks of the conventional method.

20 Structure of the Invention The structure of the present invention is as shown in FIG.
). The wrapping members (8) have a cylindrical shape, and a plurality of them are arranged so that the curvature of the outer periphery increases sequentially by l. The optical fiber (1) on the incident side is wound around members with a smaller curvature and then around larger members, and is irradiated with light from both sides by a light source (7).

According to this light input device, since the optical fiber is bent at a plurality of places to an extent exceeding the critical angle of the transmitted light with respect to the light lζ of the light source, the irradiated light enters the optical fiber at those parts. Since the curvature of the optical fiber gradually increases, the light that has emitted light is confined within the optical fiber and is completely transmitted within the optical fiber. That is, when this light input device is used, light can be input into the optical fiber on the input side at the connection location.

As explained above, the basics of the present invention are to wrap an optical fiber around a wrapping member whose bending curvature increases sequentially, place a light source on the side of the wrapping member, and irradiate light from the outside to enter the optical fiber. Of course, the arrangement as shown in FIGS. 2 and 3 is also applicable.

Further, each winding member does not have to be cylindrical, but may have an outer shape that allows the optical fiber to be shaped into a similar curve, for example, a semicircle, and furthermore, the optical fiber may be wound around the winding member a plurality of times.

The light source used in the present invention includes one that effectively contains light in the 1.3 μm band, which is the light transmitted by a single mode optical fiber;
For example, it is preferable to use a halogen lamp. It is also possible to increase the light incidence efficiency by providing a light condensing plate on the light source lamp.

E, Example Fig. 2 f As shown, the diameter is 4 mm φ, 5 MII φ, 6 M1
A device was constructed in which cylindrical wrapping members of 1φ, 7xxφ, and 8φ were arranged, and two 300W halogen lamps were arranged on both sides. It has a cooling fan that operates while the halogen lamp is on. As shown in Fig. 2, a single mode optical fiber with a clad diameter of 125 μm and a core diameter of 10 μm, coated with a UV-curable acrylate resin having an outer diameter of 0.4 nφ, is wound around the winding member of this device, as shown in Fig. 2.
The light source was turned on and light entered.

Using this method, we measured the amount of light incident on the optical fiber. The results showed that the low light intensity within the optical fiber at a distance of 1 m from the light input device was -18 dBm. That is, the amount of light was about the same level as when light enters from the normal end face.

Next, the light entrance device of the present invention was combined with a device for bending an optical fiber to receive light as shown in FIG. 5, core alignment was performed, and the optical fibers were connected. The experiment was repeated 30 times (n
=80) The average loss at the connection was 0.15d.
It was B. This loss value was comparable to that of the conventional method, and it was found that the light entrance device of the present invention can be put to practical use.

1. Effects of the Invention As explained in detail above, the light input device of the present invention, as shown in FIGS. 1 to 3, has the bending of the optical fiber and the light source arranged on the same plane, making it easy to wrap and attach the optical fiber. It is extremely easy to install and can be attached from any side of the optical fiber on the input side. In particular, instead of continuing to wind in the same direction, such as left-handed or right-handed, the windings are wound alternately around the arranged members, so
The left-handed and right-handed windings occur alternately, which not only improves workability but also prevents twisting of the optical fiber, and therefore has higher reliability against bending and breaking the optical fiber than a method of continuously bending in the same direction.

By using the light input device of the present invention, there is no need for a light source, its auxiliary equipment, or a worker at the end face of the optical fiber on the input side, that is, at a remote location, which was necessary in conventional optical fiber connections. It can receive and receive light, significantly improving the workability and economic efficiency of connection work. Moreover, the personal optical device has a simple structure, is economical, and has many effects.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present invention, FIGS. 2 and 3 are front views showing other arrangement examples of the winding members, and FIGS. 4 and 5 are respectively a conventional single mode FIG. 2 is a principle diagram showing a method of connecting optical fibers. (1)...Incoming optical fiber, 2,7...Light source (
3)...Connection point (4)...Bending type leakage light extraction device, (5)...
Glass rod type leaked light extraction device, (6)...Transmitted side optical fiber, (8)...Wrapping member

Claims (1)

[Claims] 1. An optical fiber is wound around a plurality of winding members arranged so that the curvature increases sequentially, a light source is provided on the side of the winding member, and light is introduced into the optical fiber from the side of the optical fiber. A device for introducing light into optical fibers. 2. The first aspect of the present invention is characterized in that the wrapping members are arranged so as to alternately bend the optical fibers in opposite directions, and light sources are provided on both sides so that light enters the optical fiber from the sides of the optical fiber. Light entrance device to the optical fiber described in Section 2.