JPS6123101A - Optical fiber - Google Patents

Abstract

PURPOSE:To easily set respective members at an end part of the optical fiber while reducing the attenuation of light by branching at least one end part of the optical fiber. CONSTITUTION:Light from a light source 21 when traveling to an optical fiber main body 50 through a branch fiber 53 has almost no attenuation at a joint part C1. The light passed through the optical fiber main body 50 reaches the other end part 50b. In this case, even if the half of the light passed through the joint part C2 from the right hand side of the optical fiber main body 50 travels to the branch fiber 52 and the remainder travels to an optical fiber 54, the attenuation of the light at the joint part C2 is half. Then when the light travels from the left hand side to the right hand side of the optical fiber main body 50, the quantity of attenuation of the light is 50% of the total as mentioned above.

Description

[Detailed description of the invention] [Technical field] The present invention relates to optical fibers that transmit optical signals.

[Background Art] Conventionally, when an optical fiber is used for communication, for example, it has been arranged as shown in FIG.

That is, a light source 21 is provided at one end of the optical fiber 10, and the light from the light source 21 is reflected by a half mirror 23 and then sent to the other end (the other end) via the lens 31 and the optical fiber 10. I have to. Further, an optical signal sent from the other party passes through the lens 31 and the half mirror 23 and is sent to the light receiving element 41.

On the other hand, at the opposite end (mate) of the optical fiber 10,
The members shown on the right side of the optical fiber 10 are provided.

That is, the light source 22, the half mirror 24, and the lens 3
2 and a light receiving element 42 are provided.

[Problems with the Background Art] The above-mentioned prior art has a problem in that the attenuation of the optical signal in the transmission system is large. That is, light source 2
Considering the attenuation during the time when the light reaches the light receiving element 42 from the half mirror 23, half of the light is attenuated by the half mirror 23, and another half is attenuated by the half mirror 24 on the other side. That is, roughly speaking, 3/4 of the light generated by the light source 21 is attenuated on the way.

Even when light is received by the light receiving element 41 from the light source 22 on the other side, 3/4 of the light is attenuated in total, similar to the above.

Furthermore, in the above conventional example, the half mirrors 23, 2
Adjustment of the direction of 4 is complicated, and the light source 21.22
There is also a problem in that the direction setting is also complicated.

[Object of the Invention] The present invention has been made by focusing on the problems of the above-mentioned prior art.
To reduce the attenuation of light in the transmission system as much as possible and to facilitate the setting of each member at the end of the optical fiber when transmitting optical signals in both directions of transmission and reception via an optical fiber. The purpose is to make it possible.

[Summary of the Invention] In the present invention, at least one end of an optical fiber is branched.

[Embodiments of the invention] FIG. 1 is a diagram showing an embodiment of the present invention.

In this figure, the same members as those shown in FIG. 2 are designated by the same reference numerals.

The right end 50a of the optical fiber main body 50 has a branch portion. However, the end portion 50a of the optical fiber main body 50 is formed into two branches by the branched fibers 51 and 53. There are various methods to create this branched portion, but for example, the end of another optical fiber may be welded to the end of the optical fiber main body 50. The light receiving element 41 faces the end face of the branched fiber 51, and the light source 21 faces the end face of the branched fiber 53.

At the left end of the optical fiber main body 50 in FIG.
Optical fibers are branched in the same way as above. That is,
The left end 50b of the optical fiber main body 50 is branched by branch fibers 52 and 54 to form two branches, with the end face of the branch fiber 52 facing the light receiving element 42, and the end face of the branch fiber 54 facing the light source 22. There is.

Next, the operation of the above embodiment will be explained.

First, let us consider the case where an optical signal is sent from the right side of the optical fiber main body 50 toward the left side. The light from the light source 21 is directed to the optical fiber main body 50 via the branch fiber 53. In this case, from the branch fiber 53 to the optical fiber main body 50
When the light travels, it passes through the joint C1 of the optical fiber 50, but there is almost no attenuation of the light at this joint C1. Even if attenuation occurs, it will not be attenuated by half, as in the case of reflection from the half mirror 23 in FIG.

Then, the light that has passed through the optical fiber main body 50 reaches the other end 50b. And that light is transmitted through branch fiber 5
The light passes through the branch fiber 54 and the light passes through the branch fiber 54. Here, even if 1/2 of the light goes to the branch fiber 52 and the rest goes to the branch fiber 54 when passing through the junction C2 from the right side of the optical fiber main body 50, the light attenuates at the junction C2. Only half the amount is required.

Therefore, when light travels from the right side to the left side of the optical fiber main body 50, the ends 50a1. : Since there is almost no attenuation of light in the case, the attenuation of light is only 50% of the total. Even when the light travels from the left side to the right side of the optical fiber main body 50, the amount of attenuation of the light is only 50% of the total amount, similarly to the above.

FIG. 3 is a diagram showing another embodiment of the present invention.

This embodiment shows an example of a measuring device using an optical fiber. In the figure, the right side of the optical fiber body 50 has the same configuration as the right side portion of the optical fiber body 50 shown in FIG. On the left side of the optical fiber body 50, light from the end face of the optical fiber body 50 passes through the lens 61.
The light is reflected by a mirror 60 and passes through the optical fiber body 50 via a lens 61 again. This measuring device measures, for example, the amount of transmission attenuation of light between the lens 61 and the mirror 60.

Next, the operation of the above embodiment will be explained.

The light from the light source 21 heads to the optical fiber main body 50 via the branch fiber 53, passes through the lens 61, is reflected by the mirror 60, and returns to the lens 61 and the optical fiber main body 50.
The fibers pass through and separate into branch fibers 51 and 53 at the junction C1. Here, the light returning from the optical fiber main body 50 is connected to the junction C1, and the branched fibers 51 and 5
If half of the light is branched into 3 and 3, the amount of light directed toward the light receiving element 41 will be 1/2 of the initial light amount, taking into account transmission loss along the way.

FIG. 4 shows a conventional example similar to the measuring device shown in FIG.

In this conventional example, the right side of the optical fiber 10 has the same structure as the right side of the optical fiber 10 shown in FIG. 2, and the left side has the same structure as the left side of FIG. 3. In this case, when the light from the light source 21 is first reflected by the half mirror 23, the amount of attenuation is half, and when the light reflected by the mirror 60 passes through the half mirror 23 after passing through the lens 31, the amount of attenuation is also half. is half. Therefore, the amount of attenuation of the light that enters the conventional measuring device shown in FIG. 4 ends up being 3/4 of the total.

On the other hand, in the embodiment shown in FIG. 3, the amount of attenuation is only half of the total amount, so the light transmission efficiency is high.

In addition, since the direction of the branch fiber 53 (or 54) can be changed freely, the light source 21 (or 22)
It is easy to set the direction. Furthermore, by adjusting the branched fiber to a desired length, the position of the light source can be freely set, so the distance between the light receiving element and the light source can be freely set.

In the embodiment shown in FIG. 1, the optical fibers are branched on the right and left sides of the optical fiber body 50, but the optical fibers are branched only at one end of the optical fiber body 50. It's okay. In this case, the attenuation of light is reduced only in one direction of light transmission.

Good too. That is, for example, a part of what is to become the optical fiber body 50 is polished, and the branched fiber 53 or 54 is
Polish a portion of what is to become, and bond these polished parts with adhesive. Any adhesive may be used as long as it is light-permeable.

[Effects of the Invention] The present invention improves the transmission efficiency when bidirectionally transmitting optical signals using an optical fiber, makes it easy to set the direction of the light source, and improves the connection between the light receiving element and the light source. This has the effect that the distance can be set freely.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing a conventional example, Fig. 3 is a diagram showing another embodiment of the present invention, and Fig. 4 is a diagram showing a part of the measuring device It is a figure which shows the conventional example when a fiber is used. 21.22... Light source, 41.42... Light receiving element, 5
1.52.53.54...Branch fiber, 50...
Optical fiber body, CI, C2...junction. Patent applicant: Japan Sensor Corporation

Claims (6)

[Claims] (1) An optical fiber characterized by having a branch portion at at least one end of the optical fiber. (2) In claim 1, an optical signal from a light source is supplied to the end face of one of the branched optical fibers, and a light receiving element is provided opposite to the end face of the other branched optical fiber. An optical fiber characterized by being installed. (3) The optical fiber according to claim 1, wherein the branch portions are provided at both ends of the optical fiber. (4) The optical fiber according to claim 1, wherein the branch portion is formed by welding or bonding two optical fibers to each other. (5) The optical fiber according to claim 1, wherein the optical fiber is an optical fiber for optical communication. (6) The optical fiber according to claim 1, wherein the optical fiber is an optical fiber for measurement.