JPS58168002A - Metal coated optical fiber and its production - Google Patents

Abstract

PURPOSE:To obtain a titled optical fiber which has a high m.p. and a low coefft. of thermal expansion by forming a silicon metallic layer and the other metallic layer on an optical fiber of a quartz material, heating the same and forming a stable alloy layer. CONSTITUTION:A quartz base material 21 is melted in a spinning furnace 22, and is drawn. The resulted optical fiber 23 is conducted into a chemical vapor deposition device 24, where an Si metallic layer is formed on the fiber 23 by the reduction reaction of the SiH4 and gaseous H2 supplied to the device 24. The fiber is then taken up on a reel 26. An optical fiber 25 having the Si metallic layer is drawn out from the reel 26 and is introduced into a vacuum deposition device 31 having a fore chamber 32 and a post chamber 33, where a metallic layer selected among Co, Cr, Ni, Mo, W, Pd, Pt is formed and the fiber is taken up on a take-up reel 28. The reel 28 is put in a heating furnace and is heated, whereby the stable alloy layer of the Si and the metal is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a round metal-coated optical fiber in which a metal layer is coated on an optical fiber made of a quartz-based material, and a method for manufacturing the same.

In order to improve the waterproofness and mechanical strength of optical fibers, coating them with metal layers has been carried out, and conventional metal-coated optical fibers use low-melting point metals such as aluminum and indium. However, these metals cannot withstand high temperatures due to their low melting points, and their coefficient of thermal expansion is significantly different from that of optical fibers made of quartz-based materials.
Even at low temperatures, repeated heat cycles cause peeling and cutting forces. Of course, it is preferable that the coating metal has a high melting point and a low coefficient of thermal expansion, but for example, W4
Since high melting point metals such as PMo have high melting points, it is extremely difficult to form them directly on Phino f.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a metal-coated optical fiber having a metal coat with a high melting point and a low coefficient of thermal expansion, and to provide a method for manufacturing the metal-coated optical fiber.

That is, in the present invention, Si has good adhesion at the interface with 5i02, which is the material of the optical fiber, and Cr and CG.

Ni, Mo, W, Pd, Pt, etc. are 8i and stable alloys,
This method was developed with a focus on forming so-called silicide.

First, optical fins 1 made of quartz-based material as shown in Figure 1AK.
Chemical vapor phase reaction on 1! By plasma vapor phase reaction or vapor deposition, 8i gold metal 12 is formed as shown in FIG. 1B. Next, on this Si metal layer 12, Cr, Co, Ni,
A metal layer 13 of Mo, W, Pd, Pi, etc. is formed as shown in FIG. 2C. After that, when heat treatment is applied at a temperature of 300°C to 900°C, Si of the Si metal layer 12 and any of the above metals (represented as M) of the metal layer 13 react with each other, resulting in M2
8i, MSi, BJ8i2 (DVhf and 1p (D
With a stable 'fk of 4M, so-called silicide is formed, and the central optical fiber 11 can be covered with the silicide layer 14 as shown in the first diagram. This silicide layer 14
#i All of them are very dense and have good mechanical properties as well as good resistance to moisture. Of course, it has a high melting point and a coefficient of thermal expansion of 8302. Close to 11.

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

First, as shown in FIG. 2, a quartz-based optical fiber base material 21 is melted and drawn in a spinning furnace 22, and an optical fiber with a diameter of 125 μm is spun at a speed of 60/- to form a circle. The optical fiber 423 inside was introduced into the chemical vapor phase reactor 24, and an 8-metal layer was continuously formed on the optical fiber 23. 300 cc/h of 8iH4 as raw material gas,
1 (,) was fed into the chemical vapor phase reactor 24 at a flow rate of 2800 cc/m (Q), the inside of which was maintained at 700°C by external resistance heating or an infrared heating cape, and reduced by 8iH4 HzK onto the optical fiber 23. An 81 metal layer with a film thickness of 2 μm is formed on the surface of the optical fiber 2S, and an 8i gold metal layer is formed. Reel 26 of fiber 25
It is pulled out from the chamber and passed through a vacuum evaporator 31 having a front chamber 32 and a rear chamber 33.

In this vacuum evaporator 31, CO evaporation sources are arranged around the path of the optical fibers 25 at intervals of, for example, 120 degrees, and the Si metal layer of the optical fibers 2-5 is adjusted to have a film thickness of 0.5 μm. A Co floor was formed. The nine optical fibers 27 formed with the 00 layer are wound up by the take-up reel 2B. The optical fiber 27 thus wound on the reel 28 is then placed in a heating furnace (not shown) while being wound on the reel 2B and treated at a temperature of 450° C. for 30 minutes to cause 8i and Co to react. A Co8 i 2- silicide P was formed.The optical fiber covered with the silicide layer thus made was left at a temperature of 500°C for 24 hours, and then subjected to a strength test. It was demonstrated that it has good strength and high heat resistance to low temperatures. Next, a second embodiment will be described. In this example, similar to the 10th example, a quartz-based optical fiber 4 having a diameter of 125J11cm was spun at a speed of 60 spins/- as shown in Figure 2, and a chemical vapor similar to that of the first example was used. 8 continuously during spinning in a phase reactor! Forms gold metal. 8iH4 flow rate is 150 cc/m, Hz flow rate is 1500c
c/m, once at 700°C. A Si metal layer with a thickness of 1 μm was formed on the optical fiber. A W layer is formed on these optical fibers using a chemical vapor phase reactor installed separately. That is, WF in the chemical vapor phase reactor, 5Q
Cc/sin and Hz were applied at a flow rate of 2000 cc/-, the temperature was 900°C, and the film thickness was 0.5
A W layer with μ grooves was formed. The optical fibers with the W layer formed on the 8i gold metal in this way were heat-treated at a temperature of 700°C in the same manner as in the first embodiment, and the Si and :W reacted to form the W8i. A silicide layer could be formed.

[Brief explanation of the drawing]

Figures 1A, B, C, and D are cross-sectional views of each process showing the outline of the present invention, and Figures 2i and 3 are 5J! It is a ninth block diagram explaining each process of an example. 11...Optical fiber 12...8i metal pigeon 13
...Metal layer 14...Silicide layer 21.
... Base material 22 ... Spinning furnace 23 ... Optical fiber 24 ... Chemical vapor phase reactor 31 ... Vacuum evaporator Applicant Fujikura Electric Wire Co., Ltd. Book 1 Fan 2 'lrE sugar

Claims (4)

[Claims] (1) Consists of nine fibers made of quartz-based material at the center and a stable alloy layer of a first metal of silicon metal and a second metal of another metal surrounding the optical fiber at the center. Metal coated optical fiber. (2) PJtI second metal is Cr, Co, Ni
, Mo, W, Pd. The metal-coated fiber according to item 1, in which the range of %1Itd is determined to be either Pt or Pt. (3) First layer of silicon moss on the original fiber of quartz-based material
After forming a metal layer of another metal, a second metal layer of another metal is formed on this tenth metal layer, and then heat treatment is performed to separate the silicon metal of the first gold layer and the second gold layer JI4.
A method for producing a metal-coated optical fiber, characterized by forming a stable alloy with other metals. (4) The front second metal layer is Cr, Co, Ni, Moe.
4. The method for manufacturing a metal-coated optical fiber according to claim 3, wherein the percentage image is either WtPd or l't.