JPS6027626A - Manufacture of wave-guide optical fiber for transmission of high-energy laser light - Google Patents

Abstract

PURPOSE:To manufacture a wave-guide optical fiber for the transmission of high-energy laser beam, having flexibility, by depositing a substance reflecting high-energy laser beam to the inner wall of a soda-lime glass hollow optical fiber by electroless plating. CONSTITUTION:A large-sized core glass 2a made of acid-soluble glass is inserted in a large-sized cylindrical sheath glass 1a made of soda-lime glass, and the assembly in heated at about 700-900 deg.C in a furnace 3 and drawn by the drawing roller 4 to obtain a fiber having an outer diameter of the sheath glass of about <=1,500mum and a sheath thickness of about 100-300mum. The spun glass is suspended with the tool 7 and put into a vessel 6 containing nitric acid 5 of about 1N concentration and about 70 deg.C to dissolve and remove the core glass 2b. an end of the obtained hollow sheath glass 1b is melted and sealed with the burner 8. An ammoniacal silver nitrate solution is filled in the sealed sheath glass 9 to deposit silver by the electroless silver plating process, and then, the sealed part is cut off to obtain a strong and harmless optical fiber for the transmission of high-energy laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing an optical fiber for high-power laser transmission;
In detail, it is a manufacturing method in which a material that reflects a high-power laser and uses the reflection to transmit the laser is attached to at least the inner wall of a hollow soda-lime optical fiber by electroless plating. Regarding.

For example, KR, which was conventionally used for laser transmission.
Thallium halide optical glass materials such as S-5 cannot be used for medical purposes when inserted into body cavities because they break easily due to mechanical strength such as bending and are harmful to human posture. . Furthermore, the thallium halide optical glass material is a polycrystalline optical fiber, and when a high-power carbon dioxide laser (CO2 laser) is transmitted, the crystals that make up the inner wall are melted and the transmitted light is transmitted through the optical fiber. It has the disadvantage that it leaks to the outside (called devitrification), creating a danger.

An object of the present invention is to solve the above-mentioned conventional drawbacks by utilizing a soda lime hollow optical fiber and electrolessly plating silver or copper on its inner wall, so that it has excellent flexibility and can be used inside body cavities. It is an object of the present invention to provide a method for producing an optical fiber which is harmless to the human body even when inserted into the body, and whose material is not destroyed even when transmitted with a high-power laser.

The present invention will be explained below with reference to illustrated embodiments.

As shown in FIG. 1, first, a large-diameter core glass 2a (acid-leaching glass) is inserted into a cylindrical soda-lime-based large-diameter outer glass 1a, and in this state it is placed in a heating furnace 3 for 700 minutes. The fiber is heated to a temperature ranging from 900° C. to 900° C., then stretched using a tension roller 4, and spun into a predetermined thickness. At this time, if the thickness becomes too large, the flexibility will be lost, so the stretched core glass 2
The outer diameter of the spun outer glass 1b surrounding b is 1500μ
It is preferable to spin the fiber to a thickness of about 100 to 300 μm.

The material of the core glasses 2a and 2b is borosilicate acid-leaching glass, and its composition is 15 to 35% SiO2 by weight.
%, B2O3 is 35 to 40%, BaO is 30 to 35%, and the remaining components are Na2O and K2O, both of which are about 10% in total.
The viscosity at °C is preferably about 106 poise.

Further, the cross-sectional shape of the material glass manufactured by the method shown in FIG. 1 is such that the outer glass 1b tightly covers the periphery of the core glass 2b, as shown in an enlarged view in FIG.

Next, the optical fiber that becomes the material stretched in this way is
As shown in the figure, the acid-eluted glass, which is the core glass 2b, is immersed in a container 6 containing 1N nitric acid 5 at about 70°C for about 1 to 2 hours by suspending it with a metal fitting 7. It dissolves inside. Since nitric acid 5 has entered the hollow body of the outer glass 1b after the core glass 2b has been eluted, it is necessary to wash out this nitric acid with water. After the acid has been eluted from the core glass 2b, the outer glass 1b is immersed in a separately prepared container containing water (not shown), and the nitric acid 5 is washed out with water. Furthermore, the sample is placed in a separately prepared container containing alcohol (not shown), and water is replaced with alcohol this time. At this time, in order to obtain a hollow external glass 1b with a clean inner wall, it is necessary to pour alcohol into the hollow body several times and drain the water. It should be noted that if the cleaning work is carried out in a clean booth, the cleaning effect will be further improved and a clean external glass can be obtained. Further, when the inner diameter of the hollow outer glass 1b is small, it is preferable to perform the above-mentioned cleaning operation by applying pressure.

Next, as shown in FIG. 4, one end surface of the open ends of the external glass 1b that has been cleaned is heated and melted by the burner 8, and one end surface is sealed. This process yields a sealed outer glass 9 with one end closed, as shown in FIG.

Next, a silver ammonia aqueous solution, which is a Tolen's reagent, is put into the sealed outer glass 9.

At this time, ammonium ions were added to the aqueous solution to make Ag+ ions present in the alkaline solution to form an animine silver complex [Ag(NH3)2]. To make the same aqueous solution, add 1 drop of 10% sodium hydroxide to 2 ml of 5% silver nitrate aqueous solution, and then add about 2% ammonium water to this until the silver oxide precipitate that forms disappears. create.

Next, a small amount of a reducing organic compound is added into the sealing outer glass 9 filled with the silver nitrate ammonia aqueous solution, and when it is slightly heated, the silver ions are reduced and silver is formed on the inner wall of the sealing outer glass 9. It is deposited and plated with silver (called silver mirror).

The reducing organic compound used at this time is, for example, formaldehyde, acetaldehyde, reducing sugar, tartrate, etc. The chemical reaction formula of the silver mirror reaction is as follows.

RCHO+2[Ag(NH3)2]+OH-→2Ag+
RCO2NH4+H2O+3NH3 After the above steps, a silver mirror reaction is caused and silver is deposited on the inner wall of the sealed outer glass 9, and finally.

When the sealed glass part is cut, a carbon dioxide laser (CO
Optical fibers capable of transmitting 3 lasers can be manufactured.

Next, a second embodiment of the present invention will be described.

Here, the steps up to the creation of the sealed outer glass 9 (FIG. 5) are the same as those of the first embodiment, and will therefore be omitted. First, a clean sealed outer glass 9 is filled with an alkaline copper sulfate solution. The method for preparing the copper sulfate alkaline solution at this time is to first add 3.46 g of copper sulfate (■) pentahydrate to 5
Make an aqueous solution by dissolving it in 0 ml of water. Then in another container
17.3 g of potassium tartrate and 7 g of sodium hydroxide
Make an aqueous solution by dissolving it in 0 ml of water. Next, these two types of aqueous solutions are thoroughly mixed to prepare the copper sulfate alkaline aqueous solution.

Next, the sealed outer glass 9 filled with copper sulfate alkaline solution
When a reducing organic compound is added into the glass, copper oxide (Cu2O) is deposited on the inner wall of the glass 9 by the reaction system described below. Note that examples of reducing organic compounds include acetaldehyde and bomaldehyde.

RCHO+2Cu+++40H- →RCO2H+2H2O+Cu2O where Cu++ is a complex with tartaric acid. Furthermore, metallic copper (Cu) can be obtained by heating the precipitated oxidized steel (Cu2O) together with amorphous carbon (C). The chemical reaction formula at this time is shown below.

2Cu2O+C→4Cu+Co2↑ By this method, the inner wall of the sealed outer glass 9 is filled with copper and plated with copper. Note that the precipitated copper oxide (Cu2
As a method for reducing O), the following method may be used.

First, the first method is to inject chlorine monoxide gas (CO gas) into the sealed outer glass 9 containing precipitated copper oxide (Cu2O).
By pouring the copper oxide, the copper oxide is reduced and becomes non-oxidized copper (Cu). The chemical reaction formula at that time is shown below.

Cu2O+CO→2Cu+CO2 In addition, the second method uses hydrogen gas (H2 gas) that has been dried by passing through silica gel, CaCl2, and a carbon gas desiccant as a substitute for the carbon monoxide gas used in the first method.
You can pour it in. That is, by flowing dry hydrogen gas, copper oxide is reduced and non-oxidized copper (Cu) can be obtained.

The chemical reaction formula at this time is shown below.

Cu2O+H2→2Cu+H2O And finally, the sealed external glass 9 with copper on the inner wall
By cutting the sealed portion, an optical fiber capable of transmitting carbon dioxide laser can be manufactured.

Next, a third embodiment of the present invention will be described.

A method for manufacturing a hollow optical fiber, which is a material of the present invention, will be explained with reference to FIG.

The soda-lime glass 12 is heated in a heating furnace 13 for about 700 m
While heating to ℃. By stretching with the tension roller 14, a hollow optical fiber having a predetermined thickness can be obtained. Next, while applying the necessary pressure, dilute fluorocarbon acid is poured into the above-mentioned hollow optical fiber based on soda lime to smooth the inner wall by the corrosive action of dilute fluorocarbon acid, and then alcohol is poured into the hollow optical fiber. Pour into a hollow optical fiber to clean the inner wall of the fiber.

Thereafter, by causing a silver mirror reaction by the method shown in the first embodiment and cutting the sealed portion, a hollow optical fiber capable of transmitting carbon dioxide laser can be manufactured.

Next, a fourth embodiment of the present invention will be described.

Here, in the first to third embodiments described above, electroless plating was applied only to the inner wall of the hollow optical fiber.
In this fourth embodiment, electroless plating is applied not only to the inner wall but also to the outer wall.

That is, a method for manufacturing an optical fiber for transmitting a carbon dioxide laser, which has metal cords on both the inner and outer surfaces, will be described.

First, a hollow soda lime optical fiber manufactured by the manufacturing method shown in the first embodiment or the third embodiment is prepared. Here, both the inner and outer walls of the hollow soda lime optical fiber must be clean and smooth.

Next, as shown in FIG. 7, a container 15 containing an alkaline copper sulfate solution 17 is prepared. The method for preparing the copper sulfate alkaline solution is the same as that previously described in the second embodiment of the present invention. Next, the hollow optical fiber 16, whose inner and outer surfaces have been processed to be clean and smooth, is immersed in the container 15 containing the copper sulfate alkaline solution, and a reducing organic compound such as acetaldehyde is added thereto. Then, copper oxide is deposited on the inner and outer walls of the optical fiber 16. Finally, the optical fiber 16 is taken out from the container 15 and the copper oxide is reduced by flowing carbon monoxide gas or dry hydrogen gas into the hollow body.
Copper plating can be completed using non-oxidized copper. In addition,
The chemical reaction formula for the reduction reaction using hydrogen monoxide gas or dry hydrogen gas is the same as the reaction formula described in the second embodiment.

Next, a fifth embodiment of the present invention will be described.

First, a hollow soda lime optical fiber manufactured by the manufacturing method shown in the first example or the fourth example is prepared. At this time, the inner surface of the optical fiber must be clean and smooth. Next, after filling the hollow bodies of the fibers with an alkaline solution of silver nitrate or alkaline copper sulfate using capillarity, reducing sugar or aldehyde is added dropwise to produce silver or Deposit copper. In addition, in the case of copper, it is necessary to reduce copper oxide to non-oxidized copper. Here, the chemical reaction operations for forming the silver mirror and the chemical reaction operations for electroless plating may be performed in the same manner as in the first embodiment and the second embodiment, respectively, so a detailed explanation thereof will be given below. Omitted.

As described above, according to the present invention, even when transmitting a high-power gas laser, the waveguide surface of the laser is not destroyed, and it is harmless to the human body, etc., and is inexpensive for high-power laser transmission. Waveguide optical fibers can be stably manufactured.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the manufacturing process of the raw material glass for producing the hollow optical fiber used in the present invention, Fig. 2 is an enlarged cross-sectional view of the raw material glass, and Fig. 3 is an acid elution method. 4 is a perspective view showing the sealing process of the hollow outer glass, FIG. 5 is a sectional view of the sealed outer glass, and FIG. 6 is a schematic diagram of the process of manufacturing the hollow glass used in the present invention. , a schematic diagram showing the process of manufacturing a hollow optical fiber by feeding air, and FIG. 7 is a sectional view of a plating bath showing the process of electroless plating both the inner and outer walls of the hollow optical fiber. 1a... Large diameter external glass 1b... External glass 2a... Large diameter core glass (acid elution glass) 2b.
... Core glass (acid leaching glass) 3 ... Heating furnace 4.14 ... Tension roller 5 ... Nitric acid 6 ... Container 9 ... Sealed external glass 11...Air 12...Hollow soda lime glass 16...
...Hollow optical fiber 17...Copper sulfate alkaline aqueous solution patent applicant Olympus Optical Industries Co., Ltd. Procedural Amendment (
Spontaneous) 1981/ρMon-7th 1, Incident Indication 1988 Patent Application No. 1355[]1,
Title of the invention Method for manufacturing a waveguide optical fiber for high-power laser transmission 3, Relationship to the amended person's case Address of patent applicant 2-43-2 Chogaya, Shibuya-ku, Tokyo Name Name
(037) Olympus Optical Industry Co., Ltd. 4, Agent 5, "Claims" column and "Detailed Description of the Invention" column 6 of the specification subject to amendment, Contents of the amendment (1) ""Scope of Patent Claims" will be revised as shown in the attached sheet. (2) In the seventh line from the bottom of page 1 of the specification, in the 11th line of page 2, in the second line from the bottom of page 9, and in the first line from the end of the last line of the same page.
Next to "F Soda Lime Series" listed in 0 towards the beginning of the first purchase and during the 11th purchase, respectively.
Add "Glass". (3) "-Hydrogen oxide gas J" written in the fifth line from the bottom of page 10 of the same document has been changed to "-carbon oxide gas." Attachment ``2. Claims In a method for manufacturing an optical fiber for high-power laser transmission, a hollow soda lime glass optical fiber is prepared, and at least the inner wall of the optical fiber is electrolessly plated.
A manufacturing method characterized by attaching a substance that reflects a high-power laser. ”

Claims (1)

[Claims] In a method for manufacturing an optical fiber for high-power laser transmission, a hollow soda lime-based optical fiber is created, and at least the inner wall of the optical fiber is electrolessly plated with a substance that reflects a high-power laser. A manufacturing method characterized by attaching.