JPS60103044A - Manufacture of optical fiber for infrared rays - Google Patents

Abstract

PURPOSE:To obtain a base material for an optical fiber for infrared rays with superior bonding strength between its core and clad by heat treating the inner wall of an oxide glass pipe as a clad material in a reducing gas and forming chalcogenide glass as a core material. CONSTITUTION:While introducing a reducing gas such as gaseous H2 into an oxide glass pipe as a clad material, the outside of the pipe is heated to form a metallic thin film in the pipe, and one end of the pipe is sealed by melt bonding. Metallic Ge is mixed with metallic Se, the mixture is filled into an ampul, and the ampul is sealed. The mixture is then melted by heating, mixed, and vitrified by rapid cooling to form chalcogenide glass as a core material. This core material is filled into said glass pipe and heat treated at the softening temp. of the chalcogenide glass to obtain a base material for an optical fiber. The desired optical fiber for infrared rays is manufactured by drawing the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION [First Field of the Invention] The present invention relates to an optical fiber that transmits infrared light, and relates to a method for manufacturing an optical core with good adhesiveness between the core and cladding.

[Background of the invention]

Conventionally, in the case of infrared optical fibers having a core cladding of 11ζ, the same type of material was used as the cladding material, with a buffering polymer 4'' material and a twisted core material with different composition ratios.

However, polymer materials are exclusively used for infrared light in the range of 11
The 17,000-year-old core eclipses the top of the core, and the light emitted from the core is eclipsed by 1000 yen, and the polymer is heated and hardened, resulting in deterioration of the optical fiber. In addition, the same type of 4 with different core material and composition ratio
．． t”, the refractive index difference between the core cladding is small f
The '+11 force concentration of "rme::I j" was poor, and the manufacturing method was technically difficult.

[Objective of the Invention 1 The object of the present invention is to provide a method for manufacturing an infrared optical fiber base material using oxide glass that does not cause deterioration of the fiber, which can be used in a conventional drawing process as a cladding material.

[Summary of the invention]

Chalcogenide glass is used as the core material of infrared optical fiber. Adhesive to the glass cladding! I1. 9711L, the core and cladding easily peel off due to thermal distortion, which adversely affects transmission characteristics.

These difficulties are solved by forming a thin metal film on the surface of the oxide glass by heat-treating the oxide glass in a reducing gas, and chemically bonding gold (k) and chalcogenide glass.

[Embodiments of the invention]

The present invention will be explained in detail below.

Example 1 Metal kermanium and selenium were mixed at a molar ratio of 20 to 80, and the mixture was filled and sealed in a quartz ampoule in a vacuum of 10<-2> or less. Next, boil this ampoule at 800C for 3
After melting for 9 hours, it was rapidly cooled and vitrified to 20 Ge/8
A 0 S e chalcogenide glass was created. Using this glass block as a core material, two types of optical fiber base materials (breforms) each having an oxide glass as a cladding material were produced. One is an oxide glass tube whose inner wall surface has been subjected to reduction treatment.
The other used an untreated glass tube.

A multi-component oxide glass tube (outer diameter 10 φ, inner diameter 7w + Iφ) with α=150X10-7/deg and TS=500°C selected in consideration of the thermal expansion coefficient α and softening temperature Ts of the core material.
The outer surface of the glass tube was heated to about 600 C while flowing H2 gas inside the tube until the inside of the tube turned slightly black. Next, one end of the glass tube is welded and sealed, and the chalcogenide glass block described above is filled, and while the pressure inside the tube is reduced, the chalcogenide glass is poured into the glass tube at the lowest temperature at which it softens (approximately 3,000 yen). was formed.

If this pouring temperature IJ'1 is too high, the chalcogenide glass will boil and pores will be generated, so it is desirable to keep it as low as possible. Alternatively, make a pore at one end of the glass tube, pressurize with inert gas instead of reducing the pressure, and apply a core material to 7 ohm.
When an optical fiber was drawn at 0 to 700 r and its core-clad interface was examined using an optical microscope, strong light reflection was observed at the core-clad interface in an optical fiber whose cladding was an untreated glass tube, indicating that it had peeled off. Ta.

On the other hand, the reduction-treated tube showed no peeling phenomenon and had good transmission characteristics.This is due not only to the adhesion of the core-clad interface, but also to the oxygen removal effect of the reduction treatment of the oxide glass tube. It was found that this was due to the fact that oxygen contamination from the glass was prevented and absorption loss was reduced.In addition to the above-mentioned examples, various chalcogenide glasses were also examined experimentally, and it was confirmed that the method of the present invention is effective.

Agent: Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. In a method for manufacturing an optical fiber having an infrared chalcogenide glass core, the core side wall surface of the oxide glass, which is the cladding 4A, is heat-treated in a reducing gas, and then a 1115-minute core is formed, which becomes the core of 7. A method for manufacturing an infrared optical fiber having the following characteristics: