JPS59182247A - Preparation of optical fiber of infrared rays - Google Patents

Abstract

PURPOSE:To prepare optical fiber of infrared rays having reduced absorption amount of vibration of Ge-O, by heat-treating soot glass of Ge-Se in a reducing gas atmosphere, melting it in a vacuum. CONSTITUTION:Soot glass of Ge-Se is heat-treated in a reducing gas (e.g., CO gas) having about 300cc/min flow rate at about 900 deg.C, and melted under heating to give glass block. This block is then abraded into a rod and drawn. Consequently, absorption amount of CO2 laser light having 10.6mum wavelength is reduced, and absorption position is transferred to the longer wavelength side, so that optical fiber of infrared rays transmitting CO2 laser light stably is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing Ge-8e glass that transmits infrared light, particularly light with a wavelength of 10.6 μm.

[Background technology]

In recent years, laser processing using a C02 laser (wavelength: 10.6 μm) and laser scalpels have begun to be widely used. In order to condense or bend this CO2 laser light and guide the light to a desired location, a lens or optical fiber that passes 10.6 μm light is required. For this reason, for example, as a lens, Z
n S e , KH2-5(TtBr -TtI
), a polycrystalline body consisting of KBr is used.

Also, as optical fibers KH2-5゜kgct, CsBr
Single crystals and polycrystals made of such materials are used. However, lenses and optical eyepieces made of these polycrystalline materials or single crystalline materials undergo plastic deformation due to distortion due to temperature rise, bending of the optical eyelids, etc., resulting in a significant deterioration of light transmittance. Furthermore, in the case of optical fibers made of crystalline materials, there is a drawback that the manufacturing speed is several orders of magnitude lower than that of conventional silica-based glass optical fibers.

On the other hand, glass materials do not have the problem of plastic deformation, and by using this material, Hikari 7-Iver can be manufactured at the same manufacturing speed as conventional silica-based glass. Of the glass materials, wavelength 10.6. Transparent czm are ZnC2z and GeSe.

There are GeTe, AsSe, AsTe, etc. Of these, Zn
Ctz has the disadvantage of being deliquescent, and AsSe, AsTe, etc. are highly toxic. Among Gl+Se and G@Te, G11Te has a low glass transition temperature, and the glass state becomes unstable due to the temperature rise accompanying CO2 laser light irradiation.

Therefore, the glass transition temperature is relatively high (300C)
It is considered that eSe glass is suitable as a glass material for a wavelength of 10.6 μm. However, when we investigated the light absorption characteristics of GeSe glass, we found that the wavelength of 12.
There is a large absorption at 8 μm due to Q e −Q vibration absorption. This vibrational absorption extends to a wavelength of 10.6 μm and has an adverse effect on the transmission of CO2 laser light. Note that the broken line in the figure indicates the maximum transmittance when reflection from the glass end face is taken into account.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for reducing the amount of ( ) e -Q vibration absorption of Ge-8e glass that adversely affects CO2 laser light transmission.

[Summary of the invention]

Qe-o vibrational absorption is caused by oxygen impurities in the Ge-8e glass. Therefore, by reducing oxygen impurities, the vibration absorption of Ge-o can be reduced. Based on this idea, an attempt was made to reduce Ge-3e powder with a reducing gas, especially cobalt gas, and then melt and vitrify it. Figure 2 shows how Ge-8e powder is mixed with CO gas (aoocc/m
) shows the light transmission characteristics (sample thickness: 600 μm) of a glass produced by heating at 900 C for 10 minutes and then vacuum melting (sample thickness: 600 μm) (solid line). As shown in the figure, Ge
It can be seen that the -0 vibration absorption is significantly reduced compared to when no CO gas treatment is performed (the curve shown by the broken line).

Furthermore, the absorption position has shifted to a much longer wavelength of 14 μm compared to 12.8 μm before the CO gas treatment. This means that light absorption at a wavelength of 10.6 μm, which is the oscillation wavelength of the C02 laser, is significantly reduced even if the amount of absorption remains the same. The above two effects: ■) The absorption amount itself decreases. 2) The absorption position shifts to longer wavelengths.

is very beneficial for CO2 laser light transmission.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

As starting materials, fine powders of metals Qe and Se with a purity of 99.99% were used. This powder was mixed with CO gas (flow rate: 3
It was heated to 900C in an electric furnace at 00C (/-). Heating time is 20 minutes. Thereafter, the powder (i.e., soot glass) was vacuum sealed in a quartz glass tube, and the temperature was 80°C.
After melting at 0C for 24 hours, it was cooled to room temperature to produce a glass block.

The composition of this pump is Qe: 20mot%, Se: 80
It was expressed as mot%. Next, this block was polished into a rond shape to produce a preform having a diameter of 10 mmφ and a length of 10 crn. Next, the rod was put into an F glass tube and drawn as it was to produce an optical fiber having an outer diameter of lI+01φ and a length of 1 m. The optical attenuation at the wavelength of 1006 μm for the next 7 Aipers was 0.4 dB/m. 5 to this optical fiber
When 0W C02 laser light was transmitted, long-time optical transmission was possible.

〔Effect of the invention〕

As can be seen from the above embodiments, the effect of the present invention is
．． This is extremely effective in stably transmitting 6 μm COz laser light.

[Brief explanation of drawings]

Figure 1 shows the light absorption characteristics of Qe-8e glass, and Figure 2 shows the light absorption characteristics with CO gas treatment (solid line) and without treatment (dashed line). It is a diagram. 25

Claims (1)

[Claims] A method of manufacturing an optical fiber made of oe-se chalcogenide glass, the method comprising the step of heat treating Qe-8e soot glass using a reducing gas.