JPS59216106A - Quartz system light guide and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a quartz system light guide which has good consistency with fibers and is under a little influence of the roughening of a light guide surface and the deformation of a circuit shape by providing a layer which is narrower than the light quide and has a high refractive index near the boundary surface between a glass substrate and the area of a quartz system light quide on the substrate except a light input/output part. CONSTITUTION:Metal 5 for a dopant is vapor-deposited on the quartz glass substrate 1 which is polished into a specular surface and patterned in a desired shape by fine lithography. Then, an SiO2 glass particulate layer 2a is formed thereupon. The substrate is heated to diffuse the thin film 5 into the layer 2a and make the layer 2a transparent, forming a core layer 2b. Then, a desired circuit pattern is formed by reactive sputter etching. In this case, the width of the light guide is set larger than that of a dopant diffusion part 5b. Porous quartz glass is deposited thereupon and made transparent to form a clad layer 3. Consequently, the quartz system light quide which has good consistency with fibers and is under a little influence of the roughening of the light guide surface, deformation of the circuit shape, etc., is obtained.

Description

[Detailed Description of the Invention] (Used in the field of business!) The present invention is characterized by 1. A quartz fiber optical fiber path with low loss and good readability with fibers, and a method for manufacturing the same. It is something that will help you.

(Seimei technology) The quartz glass fiber optical waveguide formed on the quartz glass substrate has good alignment with the optical fiber, and also has excellent stability and roughness.
Therefore, it is expected that it will be applied to optical super-reliable components such as optical branching and coupling circuits and optical ζ kissers.

Conventionally, the light guide path in the C building was manufactured using the process shown in Figure 1.
1 piece. Two 5IO2 threads of porous glass particles were deposited on top of the quartz glass substrate, which had been sharply polished. 5iOz porous glass is made transparent.The result is 810
2 thread core) @ 2 b can be made [Figure 31 (IJ),
:l. Finally, for example, a circuit pattern is formed by reactive substrate etching. 4 shows the waveguide interface.Finally, 5 forms a cladding layer on top of 7.
The LCh yarn is made of porous glass, and is then deposited and made transparent to form a silica glass cladding layer a2 [FIG. 1(d)].

In the method of Hatake et al., deep etching (5 to 10μ?n for 4'-mote, 5tl to 100μtn for multimode) is safe, and the conductor that generates this removed VC can be safely etched. Due to the minute irregularities on the waveguide interface 4, conventional waveguides have the disadvantage that light is easily disturbed at the interface, resulting in an optical propagation loss of 2 dB/trn or more. At the same time, due to the floor etching, the shape of the copying circuit (<'3 = rL of the turn shape is generated, and due to this 2-L,
For example, in a Y branch circuit, there is a problem in that the loss at the branch point becomes large.

(The purpose of the invention is to remove these points) to propose δtL
1ζ, by controlling the bending rate distribution r in the waveguide, it has good readability with the fiber, 7J), 9fL at the waveguide interface, 2 and the circuit shape debris 2't! - The purpose is to obtain a quartz-based optical waveguide with fewer defects.

(An older brother's grace) What is the purpose of Kamikochi? Achieving 7c, this light is placed in the quartz fiber optical waveguide on the glass substrate, and the filtering waveguide is placed close to the top surface of the substrate, excluding the nine output parts of the optical waveguide. It is also the case that the narrow oblate refractive layer is accommodated in the bamboo position and the quartz fiber optical wave path is the same as the original light of Yuanmei.

Furthermore, the present invention is to heat the raw material residue for forming a glass on a glass substrate by depositing a porous glass layer through a flame hydrolysis reaction, and then heating it to form a transparent glass, and then etching it. r') Qr ”It.

Manufacturing method Q of quartz fiber optical tied wave path forming optical circuit pattern
2. Prior to the deposition of the porous glass layer, a dopant film is formed on the glass substrate, and etched to form a ψ-shaped dopant film corresponding to the desired optical circuit pattern. Gold maple gland pattern r is formed, a-
The purpose of the invention is to provide a method for manufacturing a quartz-based light-polluting waveguide.

Next, the drawings of the embodiment of VC Fuzuremei will be explained.

It should be noted that the embodiments are merely illustrative, and it goes without saying that individual changes or improvements can be made without departing from the scope of the present invention.

FIG. 2 is a process flow chart of the manufacturing method of the non-inventive embodiment. On a 7-piece quartz glass substrate with a diameter of ψ11 mm,
Metal film 5 for dopants (for example, GeJi vapor XJ method or spac method number 500~2000^ thickness)
[Figure 2 (a)]. Next, a 5-layer metal thin film for dopant is patterned into the shape of a mouse using the usual W and granite technique (Fig. 2(b)). 8102 fibers synthesized by saponification or flame hydrolysis reaction form microscopic grains (second stage (C)). Thereafter, the substrate is heated to diffuse the dopant into the Si02 porous negative glass fine particle layer 2a, and then the 8102 yarn porous negative glass fine particle layer 2a is diffused. A dopant diffusion region Is 5 b is formed in the yarn core layer 2b' by lightening, as shown in Fig. 2 (d>). The waveguide is formed wider than the dopant diffusion region 5b by etching V (see Fig. 2).
e”]. Saisa V'-z On top of this, porous quartz glass r
The quartz glass cladding layer 3 is deposited and transparentized from the VC layer. form [Fig. 2(f)].

Due to the power of this misfire, t*LIf, the samurai also has 7'l of refraction as shown in the third attack. Figure 3 (b) is A of Ki 3 Kyo (a).
The refractive index distribution at the A' curve. Usually, the refractive index of the core J@2b is 1/1 that of the cladding layer 3 and the quartz glass substrate l.
The comb is about 1 comb thicker. 1, the dopant diffusion portion 5b has a refractive index approximately 3% larger than the refractive index of other portions of the core layer. Figure 3 (C) shows the BB' of the third prisoner (a).
This is the refractive index distribution on the surface. From here, put 4 on the wave path.
As shown by the optical power 7rXi center 6' in FIG. 3(a), the lead optical power is concentrated in the lateral direction near the core of the core, and concentrated in the thickness direction at the substrate 111111 of the core layer 2b. do. For this reason, the guided light is asymmetrically fitted, or a low-loss waveguide is formed, which is less susceptible to the effects of the roughness of the equidistant interface 4 and the small integrity of the circuit pattern.

FIG. 4 shows a top-concave diagram of a silica-based optical waveguide according to an embodiment of the present invention. The waveguide core layer 2b has a depth.

Both widths are for multi-mode use with VC50Pm, and Dornokunto diffusion capital 5b is G67. (The dopant layer is probably a diffused one.The dopant layer is removed near the edge of the wave path.)

Further, the ends of the F~ punt layer are gently tapered as shown in the figure. The power distribution of the guided light in the dopant layer is concentrated near the center of the waveguide width, so the waveguide field 11
The shadow d of the unevenness of 114 is small.

In a certain part of the diffusion capital 5b, the original power is on the board 1.
However, since there is no dopant diffusion section 5b near both ends of the waveguide, the guided light is distributed symmetrically in the waveguide. Therefore, the power distribution is very similar to that of the optical fiber, so the connection can be made efficiently and easily. The propagation loss of this waveguide was as low as 0.2 dH/CIn in the portion where the dopant diffusion M5 meets.

FIG. 5 shows a top view of a Y branch circuit according to another embodiment of the present invention. The light incident from the waveguide 6 is branched into a waveguide 7 and a waveguide 8 fL. Waveguides 6 and 7 have a line width of 50pη2
．． The waveguide 8 has a line width of 30 μm''C immediately after branching, and when the curve reaches the υ portion, the line width widens to 50 μm.The branching angle is 3°.The dopant diffusion 1155b is Ge'<diffused, The line width is 10 μm for the waveguides 6 and 7, and 3 μm for the branched portion.The end of the pattern of the dopant diffusion portion 5b is gently tapered. Fig. 6 shows the waveguide of the present invention with the dopant diffusion portion 5b. This figure shows a comparison between the power distribution within the dopant diffusion section 5b and the distribution within the conventional cross section without the dopant diffusion section 5b. When approaching this point, the 7ζ light power distributed throughout the waveguide is concentrated near the center, and the power of the light becomes one with two peaks.At the branching point 9 of the waveguide, the light power has already been divided into two. Because they are separated, even if the branching angle is rounded by 2 during the etching process, this effect will not be affected at all.After passing 9 branching points and 1
The light propagating through the four waveguides 7 and 8r gradually spreads over the entire waveguide and approaches the output end due to the power distribution of the waveguides 7 and 8r. At the output end, the power distribution is symmetrical within the waveguide, so the connection efficiency with the fiber is good. In the conventional case shown in FIG. 6(b) in which the optical power layer 5 is not attached, the optical power reaches a branch point 9 where the optical power spreads over the entire waveguide. A scattering loss occurs due to this 1ζ, the raw value t)eC of the branch point 9. ratio 5
In the case of the 1ζ non-embodiment shown in the figure, the loss due to branching is o, 2
The distribution ratio of aB, i yζ, and branches was 2:1. For comparison, in the case of the structure shown in FIG. 6 (1) without a Ge layer,
The loss due to branching was 2.4 (rare at 113).

(As the effect of radiation ψj has been surpassed, it is possible to adjust the shape of Ge Ill!, which is easy to pattern, by using the unexplored manufacturing method of quartz fiber optical waveguide.) Since the original power distribution within the waveguide can be controlled, the quartz yarn is unaffected by the roughness of the waveguide interface that occurs during the etching process to form the desired circuit pattern, and the loss cost caused by the roundness of the circuit shape. A waveguide is obtained.

1. At the connection with the fiber, it is possible to maintain the symmetry of the optical power distribution, so the connection is high! Gain efficiency.

[Brief explanation of the drawing]

FIG. 1 shows a conventional method for manufacturing a silica-based optical waveguide, FIG. 2 shows a method for manufacturing a quartz fiber optical waveguide according to the present invention, and FIG. 3 shows a refractive index distribution of an optical waveguide manufactured by the manufacturing method of the present invention. FIG. 4 is a plan view of a direct expansion optical waveguide according to an embodiment of the invention, FIG. 5 is a plan view of a main Y branch circuit according to another embodiment of the invention, and FIG. 6 is a plan view of a main Y branch circuit according to an embodiment of the invention. A comparison of the optical power distribution in the Y branch circuit and the power distribution in the Y branch circuit made by the conventional method shows the problem. l......Quartz glass substrate 2a...Porous negative glass fine particle layer 2b for core...
... S10□-based glass core layer 3 ...... Quartz glass ground layer 4 ...... Waveguide interface 5 ...... Metal thin film for dopant 5b...
. . . Dopant diffusion section 6' . . . Center of optical power distribution 6.7.8.
...Waveguide 9...... Branch point Patent applicant Japan Telecommunications Corporation Figure 1 Figure 2 Figure 3 (b) (c) A' Figure 4 b

Claims (1)

[Scope of Claims] (υ There is a quartz optical waveguide VLV on a glass substrate, and the optical waveguide Lv also has a width in the vicinity of the boundary with the substrate in a surface area excluding the optical output capacitor r of the original waveguide. heavy oil
Tsukume and 1-ru Quartz Hemoto Jinpaji. (2) After depositing a porous negative glass layer by heat printing or flame hydrolysis reaction of the tC gas forming raw material on the glass substrate, heat it to form a transparent glass, and then dry it. By etching ) How to manufacture a quartz fiber light guide path to form the desired optical circuit pattern VCυ, the porous glass layer is deposited 7i:'! ; I. A gold film for dopant is formed on a glass substrate, and a one-round pattern for dopant is formed in a shape corresponding to the desired optical circuit pattern by etching. Method of manufacturing wave channels.