JPS58115405A - Manufacture of thick film waveguide - Google Patents

Abstract

PURPOSE:To form a core layer of a quartz compound thick film waveguide, by heating only a microscopic area part on a clad layer, and generating a dot-like glass layer by a gaseous phase reaction. CONSTITUTION:A substrate 10 having a clad layer 20 is inserted into a reaction tube 50, and raw material gas 54 such as SiH4, etc. is made to flow from an inlet 52. On the other hand, an extremely microscopic area part on the clad layer 20 is spot-heated by a heating source 56, and on this part, a dot-like glass layer 32 is generated by a gaseous phase reaction. When the heating source 56 is moved by a driving device 60, the glass layer 32 is integrated linearly, and becomes a linear glass layer 34.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a single-film waveguide used for branching and merging optical fibers, and particularly relates to a method for forming a core layer of a thick-film waveguide using a quartz-based material. .

BACKGROUND AND OBJECTIVES OF THE INVENTION An example of a thick-film waveguide is shown in Figures 1 and 3. Reference numeral 10 in FIGS.

20 is a clad layer made of flat low refractive index glass such as 8102; 30 is a core layer made of high refractive index glass such as 5i02-
It is made of a thick film such as Ge02. It is drawn with a predetermined pattern and thickness on the outer and outer layers 20, and serves as a light guide layer.

Reference numeral 40 denotes a cladding layer and a cladding layer, which are made of the same low refractive index glass as the cladding layer 20, and cover the core layer 60 with a uniform thickness (not shown in FIG. 3).

Conventionally, the core layer 60 has been formed as follows.

That is, first, a thick film, which will become the basis of the core layer 60, is formed over the entire surface of the cladding layer 20. Then, a metal mask of T1.81 or the like is formed using photolithography, and a pattern is formed by dry etching using plasma.

However, this method requires a considerable thickness of etching. At present, there are no photomasks that can withstand this. It also has a beautiful cross section and does not look like cedar.

This invention makes it possible to form the core layer of a silica-based thick film waveguide without using (e) IJ sogelaf technology.

2) As shown in FIG. 1, 1) heating only a small area on the cladding layer 20 to generate a dotted glass layer 62 through a gas phase reaction; 2) heating the dotted glass layer 32; , is characterized in that it is integrated in the length direction, width direction, and thickness direction to form a core layer 60 having a predetermined pattern and thickness.

1 and 2" is a schematic explanatory diagram of the manufacturing apparatus.

50 is a reaction tube made of a light-transmitting material such as quartz. 52 is an inlet for raw material gas 54.

56 is a heating source. A device that can minutely heat a minute area on the cladding layer 20 (for example, a groove with a diameter of 20 μm) to 1500'Q through the reaction tube 50;
Or something that gives equivalent energy, such as a laser (Ar1Nd-YAGSC!02, etc.) or a lens 5
White light, etc. that is focused by 8 is used.

Reference numeral 60 denotes a driving device for the heating source 58, which is capable of accurately drawing the pattern of the core layer 60.

The raw material gas 54 includes hydrides such as SiH4 and GeH4, chlorides such as 5iC14 and GeCl4, and Si
(CH3>4, organic metal compounds such as Go (OH3)4 are used.

In order to prevent these from forming in areas other than the heated area,
Use one with thin reams.

The atmosphere inside the reaction tube 50 may be either constant pressure or reduced pressure, but the appropriate one is selected depending on the raw materials, heating method, etc.

When the raw material gas 54 is flowed into the reaction tube 50 and only a very small area on the cladding layer 20 is spot-heated by the heating source 56, the dotted glass layer 3 is formed by a gas phase reaction.
2 is generated.

When the heating source 56 is moved by the driving device 60, the dotted glass layer 32 is accumulated into a linear glass layer 34.

Next to the linear glass layer 34, there are seven more linear glass layers 6.
When 4 is added, the width expands and a planar glass layer is created.

When another glass layer is formed on the planar glass layer in the same manner as described above, the thickness gradually increases.

By repeating the above steps while controlling the pattern using the driving device 60, the core layer 30 with the desired thickness and shape is formed.
I can do it.

Incidentally, the cladding and cladding layers 20 and 40 are formed by a normal CVD method.

Example For the substrate 10, a $1 wafer of 2 x 5 m is used.

A V groove 12 with a length l 1111 is formed at both ends as shown in "Figure 3". 10μm thick in places other than V groove 12
(1) Formation of the cladding and cladding layers 20 made of Si02 film. The production is by the regular CVD method, and the flow rate at that time is SiH.

4tl cc/min, Ar 1000 cc
/min, H210/ /min, warm is 1
200°01 hour is 1.5 hours.

The thus prepared mixture was placed in the reaction tube 50.

An Ar laser is used as the heating source 56, and a small area with a variation of about 20 μm is heated by a lens 58 at 10 MW/cm.
It became possible to irradiate with the Hower Density.

The drive device 60 has an XY position that can be set in 0.1 μm increments.
Use stage.

The raw material gas 54 is 5iH420QQ/in, Ge
H44cc/min XAr 1200cc/m
The inside of the reaction tube 50 was kept under a light vacuum of 225 Torr.

A linear glass layer 34 of 5i02-Ge02 glass having a width of 50 μm and a thickness of 8 μm is formed in seven passes with a scanning speed of 10 cm/Sec. By repeating this several times on the pattern, a core layer 60 with a square cross section of 50 μm×50 μm was obtained.

A cladding 40 made of 8102 film having a thickness of 10 μm was formed thereon again by the usual CVD method.

Effects of the Invention Since the core layer 30 is formed by integrating the dotted glass layers 62, it is possible to form the core layer 30 with any desired thickness and pattern.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a thick film waveguide, FIG. 211 is a schematic explanatory diagram of a manufacturing apparatus used in carrying out the present invention, and FIG. An explanatory diagram of the state. 10: Substrates 20 and 40: Clad layer 0: Core layer 32 = dotted glass layer Patent applicant: Fujikura Electric Cable Co., Ltd.

Claims (1)

[Claims] A core layer made of high refractive index glass and having a predetermined pattern and thickness is provided on a flat plate-like layer made of low refractive index glass, and a low refractive index layer is provided on the core layer. When manufacturing a thick film waveguide with a cladding layer made of polygonal glass, only a small area on the cladding layer is heated to generate a dotted glass layer by a gas phase reaction, and the dotted glass layer is A method for manufacturing a thick film waveguide, comprising integrating the core layer in the predetermined pattern.