JPS60142309A - Positioning method of optical fiber end surface for optical fiber welding method - Google Patents

Abstract

PURPOSE:To position optical fiber end surfaces without any abutting plate by moving one opticl fiber end part toward the tip part of a photoconductor, and detecting large variation in photodetection level by a detecting means extending for optical transmission from one optical fiber to the photoconductor. CONSTITUTION:Light from an optical transmitter 9 is passed through the photoconductor 6 and projected from matching liquid 7. When the movement system for an optical fiber end part 2B is stopped through a control means, light incident on an optical fiber 1A from an optical transmitter 8 is projected from its optical fiber end surface 3A. When an optical fiber end part 2A is moved toward the mathcing liquid 7, the quantity of light incident to an optical fiber 1B increases finely as the optical fiber end surface 3A approaches to the matching liquid 7 and the quantity of photodetection of the optical fiber 1B increases abruptly when the optical fiber end surface 3A contacts the matching liquid 7. At this time, both optical fiber end surfaces 3A and 3B form a set end surface interval at their stop positions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for positioning an optical fiber end face in an optical fiber fusion splicing method.

When performing fusion splicing of optical fibers (including single mode, multimode, single fiber, multi-fiber, etc.),
Automatic fusion splicers that operate under sequence control are commonly employed.

The above devices have partial design differences depending on the type of optical fiber to be connected, but for example, devices designed for single-mode single-core optical fibers hold the optical fiber sheath in a slippable manner. A pair of left and right holders that move in the abutting direction, a groove-type or L-groove type centering stand for fitting and holding the end of the optical fiber with the coating removed between the two holders, and a centering stand for the alignment. It is equipped with an abutment plate located at the center in the longitudinal direction of the table and for setting the spacing between the optical fiber end faces that can move forward and backward in the vertical direction, a pair of discharge electrodes that are located at the end face abutment position and face each other in the front and back, and each of the above-mentioned parts. It also incorporates mechanical, electrical, and electronic control mechanisms to operate as specified.

When performing a fusion splicing method using the above device, the ends of each optical fiber are moved in the direction of abutment by a movement operation via the holder, and the end faces of each optical fiber are abutted against both sides of the abutment plate. The primary end face spacing (rough spacing) is then set.

FIG. 1 shows a state in which the mirror spacing is set in this way, and a pair of optical fibers 1A and 1B are connected to their ends 2A1.
As optical fiber 2B moves in the direction of the arrow in the figure, its optical fiber end surfaces 3A and 3B abut against the abutment plate 4.

After that, the abutting plate 4 is removed from between the optical fiber end faces 3A and 3B, and the optical core is then processed through major processes such as an alignment process for aligning the cores with each other and a discharge heat fusion process using the discharge electrodes 5M and 6N. 1A and 1B are fusion spliced.

By the way, in the method described above, when setting the end face interval, the optical fiber end faces 3A, 3B are abutted against the abutment plate 4, and the end faces are thereby positioned. There is a risk that the optical fiber end face 3A13B formed on the abutment plate 4 may be damaged by the collision with the abutment plate 4, and impurities such as minute dust adhering to the abutment plate 4 may adhere to the end face 3A s 3 B side. .

When the optical fiber end faces 3A, 3B are in such a defective state, air bubbles are generated at the optical fiber connection portion during subsequent fusion splicing, resulting in an increase in transmission loss at the connection portion or a connection failure.

In view of the above circumstances, the present invention aims to provide a new method for positioning the end face of an optical fiber without using an abutment plate that causes problems. explain.

In FIG.
3A and 3B indicate the end faces thereof, respectively.

6 is a light guide, and this light guide 6 is made of an optical fiber or a glass tube capable of guiding light inside.

7 is a matching liquid applied to the tip of the optical fiber 6, and this matching liquid 7 is applied to the optical fibers I A', I
A liquid with a refractive index almost the same as that of the core of B, is made by dissolving glycerin in an alcoholic solvent.

8.9 is a light transmitter as a light transmitting means, and 10 is a receiver 10 connected to a light receiving level detector 11.

Furthermore, in the illustrated case, the light transmitters 8, 9 are each connected to one optical fiber 1A and the light guide 6, and the light receiver 10 is connected to the optical fiber 1B).

In the present invention, as described above, the coated portions of the optical fibers: IA and 1B are held by a slip-type holder, and the optical fiber ends 2A and 12B are fitted onto an alignment stand for alignment.
This causes the optical core inos (end surfaces 3A and 13B) to face each other, and FIG. 2A shows the state of the optical core inos (ends 2A and 2B) set in this way.

In the state shown in FIG.

3B and having an angle of intersection with the abutting axis X, the light guide 6 places its tip, that is, the granular matching liquid 7, on the abutting axis X.

Furthermore, in the state shown in FIG. Matching liquid 7
It is emitted from.

In this state, the optical fiber end 2B is covered with matching liquid 7.
As the optical fiber end face 3B approaches the matching liquid Y side, the amount of light incident on the optical fiber 1B increases slightly. When the end face 3B comes into contact with the matching liquid 7, the amount of light incident on the optical fiber 1B, that is, the amount of light received, increases rapidly.

The light received at this time is P+ in FIG. 3, and the detector 11 on the light receiver 1Q side is the P+.

When this is detected, the movement system of the optical fiber end 2B is stopped via a control means (not shown), and the optical fiber end 2B is moved.
B stops at the opening in Figure 2.

After obtaining the state shown in FIG. The incident light is emitted from the optical fiber end face 3A.

When the optical fiber end 2A is moved toward the matching liquid 7 in the state shown in FIG. When the amount of light received increases slightly and the optical fiber end face 3A comes into contact with the matching liquid 7 as shown in FIG. 2, the amount of light received by the optical fiber 1B suddenly increases.

The received light level at this time is P2 in FIG. 3, and when the detector 11 described above detects P2, as described above,
The optical fiber end 2A is stopped in the state shown in FIG. 21.

When the state shown in FIG. 2 is obtained in this manner, the end faces 3A and 3B of both optical fibers form an end face interval according to the set value at the above-mentioned stop position.

In the following, the light guide 6 moves downward and away from the mating axis
．． Since the optical fibers IA and 3B are left between them, the optical connection state between the optical fibers IA and IB is maintained, and in this state, the alignment process of aligning the cores of both optical fibers with each other, that is, while checking the light reception level, is performed. Optical fiber end 2A,
2B is slightly moved vertically, horizontally, etc., and after the cores are aligned with each other, the optical fiber ends 2A and 2B are moved relative to each other, and heat is provided for fusing to these ends. Both optical fibers CIA and 1B are fused and connected to each other by (discharge heating, laser heating, etc.).

In addition, when connecting in this case, the optical fiber end faces 3A, 3B
Leave it in between! The matching liquid 7 that has been heated is evaporated by the heat of fusion.

- The method for positioning the end face of an optical fiber can be carried out with either a single-mode optical fiber or a multi-mode circular optical fiber, and can also be performed with multiple pairs of optical fibers or a tape-shaped multi-core optical fiber. However, the method can be implemented by providing a plurality of light guides 6 or by configuring the light guide 6 to accommodate a plurality of optical fibers.

Furthermore, a light receiver 10 is connected to the optical fiber 1A, a light transmitter 8.9 is connected to the optical fiber 1B and the light guide 6, or a light transmitter is connected to both the optical fibers IA and IB, and a light receiver is connected to the light guide 6. However, the method can also be implemented by appropriately turning off each light transmitter 8.9.

Further, the matching liquid 6 applied to the tip of the light guide 6 from time to time via a dropping means, a coating means, etc. may be omitted depending on the case.If the matching liquid 6 is not present, the optical fiber end face 3A, The tip of the light guide 6 may be brought close to the abutment axis X within a range that does not collide with the light guide 6. In this embodiment, for example, the optical fiber end surfaces 3A, 3B may come into contact with the light beam emitted from the light guide 6. When this occurs, a large change in the received light level is observed as described above.

1. The light guide 6 and its related parts are assembled into a fusion splicing device equipped with the holder, axis mounting table, etc. described above, and predetermined detection and control of each part are carried out by the same equipment. It is done through a computer.

As explained above, the present invention provides a method for fusion-splicing the paired optical fibers in the longitudinal direction by arranging the end faces of a pair of optical fibers to face each other and then abutting these end faces against each other. When setting the distance between the end faces of optical fibers, on the abutment axis between the end faces of the optical fibers,
or disposing the tip of the light guide close to the alignment axis,
After that, the end of one optical fiber is moved toward the tip of the light guide, and a large change in the light reception level in the light passing system is detected by a light passing detection means that spans the one optical fiber and the light guide, At the time of detection, the end of the one optical fiber is stopped, and then the end of the other optical fiber is moved toward the tip of the light guide, and the end of the other optical fiber is moved between the other optical fiber and the light guide, or both ends of the optical fiber are moved. The light passing detection means across the optical fiber detects a large change in the received light level in the light passing system, and at the time of detection, the other end of the optical fiber is stopped, so that it is possible to avoid the collision as in the conventional example. This eliminates the need for a plate, and eliminates the problems of damage and staining of the end face of the optical eye, which would otherwise occur when using the abutting means, as well as connection failures, and reduces the connection failure rate when the above abutting means is adopted. While it is 70%, in the case of the method of the present invention, this can be suppressed to almost 0%.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory drawing pointing out the problems of the conventional method, and FIG. 2 is a process explanatory drawing schematically showing one embodiment of the method of the present invention.
FIG. 3 is a diagram showing changes in the level of received light in the method of the present invention. 1A, 1B...Optical fiber 2A, 2B...Optical fiber end 3A, 3B...Optical fiber poor end 6...Light guide γ Su...Matching Liquid 8.9... Light transmitter 10... Light receiver 11... Detector X... Butt axis

Claims (3)

[Claims] (1) In a method in which the end faces of a pair of optical fibers are made to face each other, and then the end faces are abutted against each other and the optical fibers forming the slope are fused and spliced in the longitudinal direction, the distance between the end faces of the pair of optical fibers is When setting the optical fiber end face, place the tip of the light guide on or close to the abutment axis between the end faces of the optical fibers, and then align the end of one optical fiber with the tip of the light guide. while moving the white of the eye to the part, detecting a large change in the level of received light in the light passing system using a light passing detection means that spans the one optical fiber and the light guide,
At the time of detection, the end of the one optical fiber is stopped, and then the end of the other optical fiber is moved toward the tip of the light guide, and the end of the other optical fiber is moved between the other optical fiber and the light guide, or both ends of the optical fiber are moved. A method for positioning an end face of an optical fiber in an optical fiber fusion splicing method, in which a large change in the received light level in the light passing system is detected by a light passing detection means across the optical fiber, and the other end of the optical fiber is stopped at the time of detection. . (2) One optical fiber is equipped with a light receiving means, and the other optical fiber and the light guide are each equipped with a light transmitting means. Positioning method. (3) A method for positioning an end face of an optical fiber according to the optical fiber fusion splicing method according to claim 1 or 2, wherein the tip of the light guide is formed of a matching liquid.