JPS59137346A - Manufacture of glass waveguide - Google Patents

Abstract

PURPOSE:To obtain an embedded glass waveguide in a mass-producing manner while reducing the number of stages by patterning a diffusing substance on a polished glass substrate, depositing fine glass particles, and diffusing the patterned substance in a stage for converting the glass particles into transparent glass. CONSTITUTION:An SiO2 quartz glass substrate 1 is polished, the polished surface is lightly etched with an ammonium fluoride soln., and a film of metallic Ge 2 patterned by a lift-off method is deposited by a vapor deposition method using electron beams. Fine particles 4 of SiO2 quartz glass formed by causing hydrolysis in an oxyhydrogen flame mixed with gaseous SiCl4 are deposited on the substrate 1. The metallic Ge 2 converts into germanium oxide in the oxidizing atmosphere in the temp. rising stage. The substrate 1 is then annealed in a heating furnace filled with an oxidizing atmosphere. The fine particles 4 of SiO2 quartz glass are made perfectly transparent by annealing at 1,300 deg.C for 2hr. Ge ions diffuse in quartz glass in said stage for converting the fine particles 4 into transparent glass, and a waveguide having a diffusion layer 5 embedded in quartz glass is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of fabricating a buried low-loss eight-dimensional glass optical waveguide by diffusion.

The conventional method for manufacturing glass waveguides by diffusion is shown in Figure 1 (a
), a pattern film 2 of Ag, which is a diffusion source, is formed on a soda glass substrate such as BK-7, and as shown in FIG. 800～
Ag ions were diffused into the glass substrate by heating to 4100° C., and the diffused layer 8 was used as a waveguide. (References:
G., H., Hartier, P.

Jaussaud + A, D, 01iver + O
, Parriaux ” Opticalwave G
uides Published by E:Lec
tr:Lc Field Controlled
n li:xchange in Grass
“1i:1eotron, Lett, Vol.
, 1 4 , PP, 1 3 8 - 1 34.
19781 Although this method of fabrication is simple, it is impossible to realize a buried waveguide, so it has the drawback that it is difficult to make the edges so that they are not chipped and to have a 1u angle. . Moreover, since the cladding is asymmetrical, there is also the problem that the coupling loss with the C-type fiber is large.

As another method, one side of the glass substrate is immersed in a mixed salt solution containing T7+ ions, Y forms a pole on one side of the glass,
There is a method in which a platinum electrode is placed in the mixed salt solution and T+ ions are diffused into a glass substrate while applying an electric field, and this is used as a waveguide. (References: T, Ezawa an
d H. Nakagome” 0pticalWav
e Guicle Formed by Electr
ically Induced Migration o
f J, ons 1nGrassP1atesAppI
-1[)hyS-Lett, VOl, 211Pp-58
4-586° 1972) In the case of electric field diffusion, a buried waveguide is possible, but it has the drawbacks that the diffusion process is troublesome, it is difficult to enlarge the area, and it is not suitable for mass production. Furthermore, since diffusion is extremely fast in this method, control of diffusion is key, and there is a problem in that it is almost impossible to obtain a core of several μm as in a single mode waveguide.

In order to solve the above-mentioned drawbacks, the present invention aims to realize a buried waveguide using ordinary thermal diffusion.
The method is characterized in that a substance that increases the refractive index is deposited on a substrate and then diffused during the process of making the glass imitation particles transparent.

FIGS. 2(a), (b), and (c) show the steps of an embodiment of the present invention. In this example, a method for manufacturing an optical waveguide in 5j-o2 quartz glass will be described.

In Figure 2, 1 is 5108 quartz glass and G is inside the quartz glass.
e metal (diffusion source), 4 is 8102 quartz glass particles, 5
The Get diffusion layer 6 is a SiO □ quartz glass transparent layer 0 First, the Sio, quartz glass substrate 1 is polished, and the polished surface is lightly etched with ammonium fluoride solution.
), a film of Ge metal 2, which has been turned into a butter by the lift-off method, is deposited by electron beam evaporation at a thickness of 500 for a single mode and 2000 for a multimode. The pattern shape is 8 μm in width for single mode, 80 μm in width for multimode, and 4'0 in length for both.
'mm. A hydrothermal decomposition reaction is carried out on this substrate in an oxyhydrogen flame of H2 and 02 mixed with s iCl 4 gas, and the generated Sx02 silica glass particles 4 are deposited as shown in FIG. 2(b).

Ge metal 2 changes into germanium oxide (GeO,) during the temperature rising process of the oxidizing atmosphere. In addition, the thickness of the deposited layer of SiO□ quartz glass fine particles 4 is 200~
300 pm, multi-mode timing 800-100
It is 0 μm. The deposition temperature is approximately 400°C. Next, this substrate is placed in a heating furnace in an oxidizing atmosphere, and for single mode use, it is annealed at 1150°C for 5 hours, and then further heated to 1800°C.
The temperature was raised slightly and annealed for another 2 hours, and for paper sheets to multi-modes, annealed at 1150°C for 100 hours, then 1800°C.
The temperature was raised to 0.degree. C., and annealing was further performed for 2 hours. The 810□ quartz glass fine particles 4 become completely transparent when annealed at 1000° C. for 2 hours. As shown in Figure 2 (0), the ae ion is
5108 Quartz glass diffuses into the quartz glass during the transparent vitrification process, and the diffusion layer 5 becomes a waveguide embedded in the quartz glass. Next, the end face of the waveguide was polished.The characteristics of the produced waveguide were as follows: a single mode optical fiber with a wavelength of 1.
As a result of fully introducing the 3 μm semiconductor laser beam, the near-field pattern of the 8 μm wide pattern for single mode was completely single mode, and the propagation loss was 0.1 dB/crn. The connection loss between the waveguide 5 and the single mode optical fiber was 0.2 dB when a matching liquid was used, which was an extremely low value.

As a deposition method in 8102 quartz glass, Ge
A 8102 quartz glass substrate with a pattern and a shape formed thereon was set in a heating furnace maintained at a temperature of 0 to 1100°C, and 5iO
It is also possible to flow a mixed gas of 7 and 02.

Also, as a diffusion source, substances other than G8 A+Ti+Zr+S
b, Sn oxide and oxide A40, TiO
2, Zr2O3゜8 Sb205+ SnO,! With Ago, it is also possible to fabricate a diffused optical waveguide under conditions where Siog quartz glass does not crystallize.

Furthermore, the method of the present invention can be applied to ordinary multicomponent glass as long as the same multicomponent glass particles as those on the substrate can be deposited. In this case, the conditions are that the glass to be deposited has approximately the same coefficient of thermal expansion as the substrate glass, and the refractive index of the deposited glass is smaller than, and approximately equal to, the refractive index of the substrate glass.

Note that since the substrate glass also softens during the transparentization process, a material with a higher softening temperature than the substrate glass must be used as the sample setting table.

As explained above, according to the method for manufacturing a glass waveguide of the present invention, embedded glass waveguides can be realized in mass production with extremely few steps. , can be applied to low-cost optical circuits. In particular, the present invention has the advantage that a Si02 quartz glass waveguide by diffusion, which was conventionally thought to be nearly impossible, can be easily produced.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are process diagrams for manufacturing a glass waveguide using conventional diffusion, and FIGS. 2(a), (b), and (C) are process diagrams for an embodiment of the present invention. 1... Glass substrate 2... Diffusion source 3.5...
- Diffusion layer or waveguide 4...Glass particles 6 of the same structure as the substrate glass...
Transparent glass layer patent applicant Nippon Telegraph and Telephone Corporation Figure 2

Claims (1)

[Claims] 4. After patterning the diffusing substance into a film and desired shape on a polished glass substrate, the glass imitation particles are exposed to O.
A method for producing a glass waveguide, characterized in that the diffusion substance is deposited on the substrate by a VD method or a flame torch, and the diffusion substance is diffused in the process of being made into transparent glass at high temperature, thereby forming an optical waveguide. In the method for manufacturing a glass waveguide according to claim 1, Ge or Al is used as the diffusing substance. Ti, Z-r, Sb, Nb, Ta,
Sn, Ag and its oxide G302+
1203. Tie□. Zr2O3,5b205. Nb2O5, Ta205.
A method for manufacturing a glass waveguide characterized by using SnO2°AgO. 8. Feature #'f In the method for manufacturing a glass waveguide according to claim 1, a method for forming a 3102 quartz glass waveguide on an 8102 quartz glass substrate to which a diffusion source is attached includes 5iOl and 02 s i,o onto the substrate placed in a heating furnace. In the process of depositing on a quartz glass substrate or flowing SIC14 into a H2 and 02 flame, depositing 8102 quartz glass imitation particles on the substrate, and making the 5i02 quartz glass imitation particles transparent at high temperature, the patent A method for producing a glass waveguide, comprising diffusing the diffusing substance according to claim 2.