JPS5857372B2 - Optical fiber glass manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing optical fiber glass capable of producing high quality optical fibers.

The most important properties required of optical fibers are low loss and wideband performance.

Optical fibers that meet these characteristics are obtained by spinning optical fiber materials obtained by chemical vapor deposition of a glass film on the inner wall of a glass tube or chemical vapor deposition of optical fiber glass on the outer wall of a core material. There is.

However, although optical fibers obtained by chemical vapor deposition generally have high performance, their properties vary widely and it is difficult to manufacture them stably and with good reproducibility.

This relies on the difficulty of controlling chemical vapor deposition methods.

An object of the present invention is to improve instability when forming optical fiber glass by chemical vapor deposition, and to provide an apparatus that can stably and reproducibly produce desired high-quality optical fiber glass.

According to the present invention, there is provided a carrier gas supply source, a raw material container capable of housing a liquid raw material for optical fiber glass and into which the carrier gas can flow, and a temperature control for controlling the temperature of the liquid raw material. and means for exciting a gas mixture of the carrier gas and a gas vaporized from the liquid raw material to form the optical fiber glass by a chemical reaction, wherein the raw material container contains: An apparatus for producing optical fiber glass is obtained, which is provided with a reduction amount detection means capable of detecting the amount of reduction in the volume of the liquid raw material.

Further, according to the present invention, the reduction amount detection means irradiates the surface of the liquid raw material in the raw material container with a sharply directional light beam, and detects the amount of displacement of the reflected light beam from the liquid surface with a photodetector. Thus, an apparatus for manufacturing tip fiber glass that detects the amount of decrease in the liquid raw material is obtained.

Furthermore, according to the present invention, as the reduction amount detection means,
The intensity of interference light obtained by irradiating a first light with good monochromaticity almost perpendicularly to the liquid surface of the liquid raw material in a raw material container and making a part of the reflected light interfere with a second light with good monochromaticity. An optical fiber glass manufacturing apparatus is obtained that detects the amount of decrease in the liquid raw material by detecting the amount using a photodetector.

Next, the present invention will be explained using the drawings.

FIG. 1 shows a first embodiment of the present invention, in which 1 and 2 are oxygen supply sources that supply oxygen which also serves as a carrier gas and a reaction gas;
and 4 are glass containers, and 5 and 6 are liquid raw materials for optical fiber glass, 5iCl and GeCl4.1, respectively.
and 8 are liquid raw materials 5iC745 and GeCA46
9 and 10 are light sources of sharply directional light beams; 11 and 12 are photodetectors;
13 is a tube on which an optical fiber glass is deposited, and 14 is a heating element.

In the above configuration, oxygen from oxygen supply sources 1 and 2 goes to glass containers 3 and 4, respectively, and 5iC
1! +5 and GeCA,6 gases are carried away, respectively.

The 5ick4 GeC74 gas carried out is mixed on the way and sent into the tube 13.

The mixed gas of oxygen 5iC74 and GeCA4 inside the tube 13 is heated by the heating element 14 to cause a chemical reaction and is deposited on the inner wall of the tube 13 as optical fiber glass.

When the heating element 14 is moved in the length direction of the tube 13, the tube 13
Optical fiber glass is deposited uniformly along its length on the inner wall of the optical fiber.

By changing the amount of oxygen supplied from the oxygen supply sources 1 and 2, a multilayer optical fiber glass film having different component ratios can be formed.

By the way, while performing such chemical vapor deposition, 5iC
145 and GeCl 46 decrease, and this decrease is detected using the light beams from light sources 9 and 10.

That is, the light beam is 5iCl. 5 and GeCl! 46
are reflected from the liquid surface and reach photodetectors 11 and 12, respectively.

Changes in the liquid levels of 5iC745 and GeC7,6 are detected by photodetector 1.
This corresponds to changes in the positions of the light beams incident on 1 and 12, respectively.

That is, a uniform optical fiber glass film is obtained by detecting the amount of change in the reflected light beam and operating the temperature control devices 7 and 8 so that this amount remains constant.

By setting the amount of change in advance, it is possible to form a uniform multilayer optical fiber glass in which each layer has a different component ratio.

FIG. 2 shows a second embodiment of the present invention, 1 and 2 are oxygen supply sources, 3 and 4 are glass containers, 5 and 6 are respectively 5iCA and Ge C13, 7 and 8 are temperature control devices, 21 22 is a first light source that emits light with good monochromaticity; 23 and 24 are second light sources that emit light with good monochromaticity; 25 and 26 are light intensity detectors; 13 is a tube; and 14 is a heating element.

In the above configuration, as in the case of the first embodiment, oxygen, 5ic14. A gas mixture of GeCl undergoes a chemical reaction inside the tube 13 and is deposited on its inner wall.

At this time, the amount of decrease in the liquid raw materials 5iC145 and GeCl46 is determined by the amount of light emitted from the first light sources 21 and 22 reflected from the liquid surface of 5iC145, GeC, and g46, respectively, and the light from the second light sources 23 and 24. The respective interference lights are received by detectors 25 and 26, and their light intensities are detected.

Since the amount of decrease in the liquid raw material corresponds to the amount of decrease in the liquid level, the light intensity of the interference light also changes at the same time.

That is, a uniform optical fiber glass film can be obtained by detecting the amount of change in light intensity and operating the temperature control devices 7 and 8 so that this amount remains constant.

Furthermore, by setting the amount of change in advance, it is possible to form a large amount of uniform optical fiber glass films with different component ratios.

In the first and second embodiments, the optical fiber glass was deposited on the inner wall of the tube, but it is clear that it is also possible to form the optical fiber glass on the outer wall of the core material or simply obtain a powdered optical fiber glass. It is.

Further, in the above embodiment, a method was explained in which the oxygen of the carrier gas passes through the surface of the liquid raw material, but it is of course possible to use a system for generating a gaseous raw material in which the carrier gas is pushed out from inside the liquid raw material. .

In addition, in this example, in order to simplify the explanation, 5iC14
Although two types of liquid raw materials were used, namely, and Ge C114, it is clear that a number of different liquid raw materials may be used.

Further, although a heating body is used as a means for exciting the gas mixture for forming the optical fiber glass, it is of course possible to use other excitation means such as electric field excitation.

Finally, a feature of the present invention is that since the amount of gas generated as a raw material for optical fiber glass is constantly controlled, high quality optical fiber glass can be formed uniformly and stably.

Furthermore, since the amount of raw material gas generated can be precisely set, uniform optical fiber glass can be manufactured with good reproducibility.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are diagrams showing the first and second embodiments of the present invention, respectively, in which 1 and 2 are oxygen supply sources;
3 and 4 are glass containers, 5 is S i C14, 6 is G
e C14, 7 and 8 are temperature control devices, 9 and 10
is a light source, 11 and 12 are photodetectors, 13 is a tube, 14 is a heating element, 21 and 22 are a first light source that emits monochromatic light,
23 and 24 are second light sources that emit monochromatic light, and 25 and 26 are light intensity detectors.

Claims (1)

[Scope of Claims] 1. A supply source of carrier gas, a raw material container capable of storing a liquid raw material for optical fiber glass and into which the carrier gas can flow, and a temperature for controlling the temperature of the liquid raw material. An apparatus for producing optical fiber glass comprising a control means and a means for exciting a gas mixture of the carrier gas and a gas vaporized from the liquid raw material in order to form the optical fiber glass by a chemical reaction, wherein the optical fiber glass is housed in the raw material container. An apparatus for manufacturing optical fiber glass, characterized in that the apparatus is provided with means capable of detecting a decrease in the volume of the liquid raw material. 2. A sharply directional light beam is irradiated onto the surface of the liquid raw material in the raw material container, and a photodetector detects the amount of displacement of the light beam reflected from the liquid surface to detect the amount of decrease in the liquid raw material. An apparatus for manufacturing optical fiber glass according to claim 1. 3 The intensity of the interference light obtained by irradiating the first light with good monochromaticity almost perpendicularly to the surface of the liquid raw material in the raw material container and interfering with the reflected light and the second light with good monochromaticity is calculated. 2. The optical fiber glass manufacturing apparatus according to claim 1, wherein the amount of decrease in the liquid raw material is detected by a detector.