JPH0943447A - Fusion splicing device for optical fibers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the optimum combination of time and the accuracy of a measured value by changing over the observation at the time of fusion splicing of optical fibers by TV cameras to a high magnification and low magnification at need with a simple mechanism. SOLUTION: The two cameras; the TV camera 41 for the low magnification and the TV camera 42 for the high magnification are used. These cameras are so constituted that the light emitted from an objective lens 30 and transmitted through a half mirror 60 enters the TV camera 41 for the low magnification and that the light reflected by the half mirror 60 is reflected again by the mirror 62 and enters the TV camera 42 for the high magnification through the longer optical path. The optical fiber image larger than the optical fiber image of the TV camera 41 for the low magnification is obtd with the TV camera 42 for the high magnification. The simultaneous observation of all the optical fibers 20 with the TV camera 41 for the low magnification and the macroobservation of only one piece of the optical fiber with the TV camera 42 for the high magnification are made possible by changing over the output of both TV cameras 41, 42 at need.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fusion splicing device for optical fibers, and more particularly to a fusion splicing device for multi-core optical fibers, and more particularly, for observing an optical fiber using an objective lens and a TV camera therein. It is about parts.

[0002]

2. Description of the Related Art FIG. 3 schematically shows an example of a conventional optical fiber observing means. 20 is an optical fiber, 30 is an objective lens, 40 is a TV camera, 50 is a TV monitor, 52
Is the screen.

When the optical fiber 20 is fusion-spliced, the following steps are observed. FIG. 4 shows the monitor screen 52 at each step. The optical fiber 20 in FIG.
To be precise, it is an image of an optical fiber, but since it is complicated to explain, it is simply referred to as an optical fiber.

A step of setting the distance between the end faces of the optical fiber (FIG. 1 (a)). While advancing while measuring the distances d _{1 to} d ₄ between the optical fibers 20 facing each other, the optical fibers 20 are stopped when reaching a predetermined value. Step of estimating connection loss ((b) of the same figure). The axial misalignment x ₁ ~x ₄ of each optical fiber 20 is measured to estimate the connection loss from those values. If necessary, move the optical fiber so that the misalignment is zero. A step of melting and connecting the optical fiber with the heat of discharge (FIG. 2C). Reference numeral 54 is an image of arc discharge. The step of evaluating the connection loss ((d) in the figure). Image processing is performed on the fused optical fiber to calculate the loss.

In the conventional multi-core device, the optical fiber 20 is observed by using the objective lens 30 having a low magnification in each of the above steps. This method has the advantage that it does not take time because all the optical fibers can be observed at once, but it has the disadvantage that the accuracy of the measured values is poor because of the low magnification.

There is also a method of using a high-magnification objective lens 30 such that one optical fiber 20 can be seen on the monitor screen 52 in order to improve the accuracy of the measured value. However, this method takes time because the TV camera 40 is moved by the number of the optical fibers 20 and the observation is repeated.

[0007]

Among the above-mentioned fusion splicing steps, • does not require so high accuracy of measured values, and low magnification is required.・ However, the higher the accuracy of the measured value, the better. If you can increase or decrease the magnification as needed,
The optimum combination of time and measured value accuracy can be achieved. However, it is difficult to arrange a plurality of lenses near the optical fiber 20 like a microscope.

[0008]

As illustrated in FIG. 1, two low magnification TV cameras 41 and a high magnification TV camera 42 are used. A half mirror 60 is placed between the objective lens 30 and the low magnification TV camera 41.・ And the light transmitted through the half mirror 60 is T for low magnification.
Light entering the V camera 41 and reflected by the half mirror 60 is allowed to enter the high-magnification TV camera 42. The distance from the objective lens 30 to the high-magnification TV camera 42 is the distance from the objective lens 30 to the low-magnification TV camera 4
It should be longer than the distance to 1. The low-magnification TV camera 41 and the high-magnification TV camera 4
The positions of 2 may be exchanged.

[0009]

[Operation] TV for higher magnification than TV camera 41 for low magnification
Since the camera 42 has a longer distance to the objective lens 30, the image of the optical fiber 20 is larger. Objective lens 30
To the low-magnification TV camera 41 and the distance from the objective lens 30 to the high-magnification TV camera 42 are appropriately selected so that the low-magnification TV camera 41 simultaneously observes all the optical fibers 20. With the TV camera for magnification 42, only one optical fiber 20 can be magnified and observed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 41 is a low magnification TV camera and 42 is a high magnification TV camera. However, these are different only in use, and may have the same specifications. A half mirror 60 is placed between the objective lens 30 and the low-magnification TV camera 41 so that light from the objective lens 30 passes through the half mirror 60 and enters the low-magnification TV camera 41. Further, a mirror 62 is provided, and the half mirror 6
The light reflected by 0 is reflected by the mirror 62 again and enters the high-magnification TV camera 42.

The image magnification of the low-magnification TV camera 41 is about 5 times. The distance of the objective lens 30 to high-magnification TV camera 42 _{(A 1 + A 3 + A} 4), the distance of the objective lens 30 to a low-magnification TV camera 41 (A ₁ + A ₂₎
The image magnification by the high-magnification TV camera 42 is set to about 20 times. The outputs of the low-magnification TV camera 41 and the high-magnification TV camera 42 are switched by the switch 64.

Then, in the step of setting the end face spacing and the step of discharge fusion welding, which are described in the above paragraph [0004], the low magnification TV camera 41 is used to observe at a low magnification (FIG. 1). (A)). In addition, in the step of estimating the splice loss and the step of evaluating the splice loss, the magnification is set to a high enough degree to observe one optical fiber 20 using the high-magnification TV camera 42 (see FIG. 1).
(B)). At this time, the high-magnification TV camera 42 is displaced in the direction of the arrow 44 so that all the optical fibers 20 are moved to the position of 1.
Be able to observe each book. It is also possible to shift the observation position of the optical fiber by rotating the mirror 62 without displacing the TV camera 42.

It should be noted that the mirror 62 may be omitted and the configuration shown in FIG.

[0014]

【The invention's effect】

(1) Since the magnification can be easily switched, the magnification can be increased only when necessary to improve the accuracy of the measured value. (2) Since only one lens is used for switching the magnification, a mechanism for switching the lens is unnecessary.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory view of another embodiment of the present invention.

FIG. 3 is a schematic explanatory view of an example of a conventional optical fiber observation means.

FIG. 4 is an explanatory diagram of a monitor screen of each step observed during fusion splicing of optical fibers.

[Explanation of symbols]

 20 optical fiber 30 objective lens 40 TV camera 41 low magnification TV camera 42 high magnification TV camera 50 TV monitor 52 monitor screen 60 half mirror 62 mirror 64 switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Manabu Kubota 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Masahiko Mikawa 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. A fusion splicer for optical fibers having an optical fiber observing means including an objective lens and a TV camera, wherein a TV camera for the optical fiber observing means is provided for low magnification and for high magnification. A half mirror is placed between the low-magnification or high-magnification TV camera and the objective lens, and the light transmitted through the half-mirror enters either the low-magnification or high-magnification TV camera. The light reflected by the half mirror enters the other of the low-magnification or high-magnification TV camera, and the distance from the objective lens to the high-magnification TV camera is from the objective lens to the low magnification. Optical fiber fusion splicer that is longer than the distance to the TV camera.