JPH0597458A - Optical fiber base material processing method - Google Patents

Abstract

(57) [Abstract] [Object] The present invention provides a method for processing an optical fiber preform that optimally polishes and separates the tip of the optical fiber preform in pretreatment performed before the optical fiber preform is sent to a drawing process. The purpose is to provide. In order to achieve such an object, the present invention grips both ends of the optical fiber preform 6 before the drawing step and heats the vicinity of the lower end of the optical fiber preform 6 with a flame of a burner to remove the tip. In the step of cutting and forming, the cutting burner 17 and the polishing burner 27 are provided, and the cutting burner 1
In the processing method of the optical fiber preform, the tip of the optical fiber preform 6 is separated by 7 and the optical fiber preform 6 is polished by the polishing burner 27.
By using 7 and 27 properly, extremely efficient work characteristics can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing an optical fiber preform that optimally polishes and separates the tip of the optical fiber preform in a pretreatment before sending the optical fiber preform to a drawing process. is there.

[0002]

2. Description of the Related Art Conventionally, when manufacturing an optical fiber,
First, an optical fiber preform is first produced, and this preform is drawn and thinned (fiberized) to manufacture. In this drawing, as a pretreatment, one end of the optical fiber preform obtained by the VAD method or the external attachment method is cut off,
It is necessary to carry out staking and flame polishing, and conventionally, for example, an apparatus system as shown in FIG. 4 is used.

For example, the optical fiber preform (quartz rod) 6 is held between the upper and lower frames 2 and 3 of the vertical glass lathe 1 via the chucks 4 and 5, and the optical fiber preform 6 is held. While rotating, a flame is blown from the oxyhydrogen burner 7 that is vertically moved by the traverse mechanism 8 on the lathe 1 side,
The vicinity of the lower end of the optical fiber preform 6 is heated to separate the front end, and the lead-out process is performed.

In the actual tapping process, when the lower end of the optical fiber preform 6 is softened by heating, for example, the lathe 1 described above is used.
Lower the lower frame 3 in the direction of arrow A to separate it,
At the same time, the tip of the base material is made into a thin tip shape so that the wire drawing can be performed smoothly, and a part of the base material is ground by a flame during polishing.

[0005]

However, in the above-mentioned conventional apparatus system, the oxyhydrogen burner 7 is used in the above-mentioned separation and polishing of the base material tip, so that there are the following problems. .. In other words, in the process of separating the base material tip,
While a burner with a slow gas flow rate is preferable, a burner with a fast gas flow rate is preferable in the flame polishing process.
In the above conventional system, which has only one oxyhydrogen burner 7,
It was difficult to carry out both tasks efficiently.

The present invention has been made in view of the conventional circumstances as described above, and is characterized in that two burners for cutting and polishing are provided, and each of these burners is used for its own work. It is an object of the present invention to provide a method of processing an optical fiber preform that enables efficient work by properly using it.

[0007]

The method for processing an optical fiber preform according to the present invention is such that the both ends of the optical fiber preform before the drawing step are gripped, and the vicinity of the lower end of the optical fiber preform is provided with a burner. In the process of heating with a flame to separate the tip, and in the process of forming a lead, a cutting burner and a polishing burner are provided, the cutting burner cuts the tip of the optical fiber preform, and the polishing burner cuts the light. It is a method of processing an optical fiber preform for polishing a fiber preform.

[0008]

As described above, according to the present invention, since the burner for cutting and the burner for polishing are provided, the optimum burner can be used according to each work, and extremely efficient work characteristics can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a processing apparatus for carrying out the method for processing an optical fiber preform according to the present invention. The apparatus shown in the figure is almost the same as the apparatus system shown in FIG. 4 described above, but in the present apparatus, the cutting burner 17 and the polishing burner 27 which are vertically moved by the two traverse mechanisms 18, 28 on the lathe 1 side. Is provided.

Since the separating burner 17 uniformly heats the entire part of the lower tip of the optical fiber preform 6 to be separated, the gas flow velocity is slow, for example, 7 m / m.
A burner having a wide range of flame characteristics corresponding to the outer diameter (diameter) of the base material is preferable. On the other hand, since the polishing burner 27 scrapes the surface of the optical fiber preform 6 with a flame, the gas flow velocity is high, for example, 10 m /
Set to about a minute. The setting of the gas flow velocity and the like is not particularly limited, but may be adjusted, for example, by changing the number of nozzles. That is, the disconnection burner 1
In No. 7, more nozzles (for example, 13 nozzles) are widely arranged to blow a wide range at a low flow velocity, and in the burner 27 for polishing, a small number of nozzles (for example, 9 nozzles) are narrowly arranged, It is recommended to spray it in a narrow area with a strong flow velocity.

To carry out the method of the present invention using such an apparatus, the following steps are carried out. First, in order to cut off the lower tip of the optical fiber preform 6, the above-mentioned cutting burner 17 is used, and a flame of a slow gas flow rate from this cutting burner 17 is blown to the cut part of the optical fiber preform 6, When the part is heated uniformly and softened to an optimum state, for example, the lower frame 3 of the lathe 1 is pushed down in the direction of arrow A to be separated. On the other hand, in order to scrape the optical fiber base material 6 by flame polishing, the polishing burner 27 is used, and a flame with a high gas flow rate from the polishing burner 27 is strongly blown to the optical fiber base material 6 to polish it by the flame. , Remove dust adhering to the surface.

By the way, regarding the cutting off of the base material tip and the flame polishing by the method of the present invention, the cutting burner 17 and the polishing burner 2 are used.
The results obtained by using both No. 7 and No. 7 are as shown in FIG. 2 (separation characteristic diagram) and FIG. 3 (polishing characteristic diagram). In addition,
Here, the nozzle structure of the disconnecting burner 17 is
The total number of nozzles is 13 by arranging 4 and 8 double around this, and the nozzle structure of the polishing burner 27 has 1 nozzle in the center and 8 nozzles around it. The number of nozzles is nine. Regarding the gas flow velocity, the polishing burner 27 side is larger than the separating burner 17, and the gas flow velocity ratio is such that the polishing burner 27 side: the separating burner 1
7 = 1: 0.7. The outer diameter of the base material used was 60 mm, and the flame polishing time was 6 minutes.

According to the separating characteristic diagram of FIG. 2, the polishing burner 27 takes 60 minutes to separate, whereas the separating burner 17 can separate in about 35 minutes, which is about 1/2. It can be seen that a burner having a slow gas flow rate is preferable. Further, according to the polishing characteristic diagram of FIG. 3, as compared with the cutting burner 17, regardless of the distance from the nozzle end to the base material surface, the polishing burner 2
Since the amount of polishing by 7 is about 2-3 times as large, it is understood that a burner with a fast gas flow rate is preferable for flame polishing.

In the above embodiment, the vertical glass lathe 1 was used, but the method of the present invention is not limited to this, and can be applied to the case of using a horizontal glass lathe. Is.

[0015]

As is apparent from the above description, the optical fiber preform processing method according to the present invention has two burners for cutting and polishing, so that the optimum burner is suitable for each work. Can be used and very efficient working characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of a processing apparatus for carrying out a method for processing an optical fiber preform according to the present invention.

FIG. 2 is a characteristic diagram showing separation characteristics by a separation burner and a polishing burner.

FIG. 3 is a characteristic diagram showing flame polishing characteristics by a separating burner and a polishing burner.

FIG. 4 is a schematic explanatory view showing an apparatus system for carrying out a conventional method for processing an optical fiber preform.

[Explanation of symbols]

 1 Lathe 6 Optical Fiber Base Material 17 Cutting Burner 27 Polishing Burner 18 Traverse Mechanism 28 Traverse Mechanism

Claims (1)

[Claims] 1. In the step of gripping both ends of the optical fiber preform before the drawing step and heating the vicinity of the lower end of the optical fiber preform with a flame of a burner to separate the tip, and performing the process for forming a lead, for cutting. A method of processing an optical fiber preform, comprising providing a burner and a polishing burner, separating the tip of the optical fiber preform by the separating burner, and polishing the optical fiber preform by the polishing burner.