JPH10293220A - Manufacture of light guide and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacture for a light guide and its device which can machine a substrate into a desired shape with high precision by using a laser with good productivity. SOLUTION: The laser light outputted by a laser oscillator is made incident on a mask 16 for optical processing by a specific optical system. This mask 16 has a window 18 formed in the high intensity area PC of the beam BS. Consequently, the laser beam which is transmitted through the mask 16 has a high and uniform intensity distribution. When a substrate 14 is irradiated with this laser beam, the substrate 14 is worked into an excellent shape conforming with the beam shape and such trouble as the generation of a striped trace at a recessed part 20 is no generated, so that the lightguide can be formed precisely and beautifully.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing an optical waveguide using laser light.

[0002]

2. Description of the Related Art An optical waveguide is used, for example, for branching or coupling of an optical fiber used for optical communication. Optical waveguides can be coated, deposited, sputtered, CV
D, polymerization, thermal diffusion, ion exchange, etc. Quartz (glass) is generally used as an optical material for optical communication components, and various components have been manufactured. However, the production of parts made of quartz requires a considerably high temperature, and the workability is not always satisfactory. Therefore, a plastic material which is flexible and has excellent workability is being studied as a material to replace the quartz.

[0003] In general, plastic materials have drawbacks such as inferior heat resistance and light loss cannot be said to be sufficiently low. In particular, polyimide is excellent in heat resistance among plastics, and recently, it is transparent and has low loss. And have been noted as materials for optical waveguides (for example, Japanese Patent Application Laid-Open Nos. 4-98007, 4-235505, and 4-2).
35506).

In an optical waveguide, it is necessary to control the refractive index between a light-transmitting core layer and a light-reflecting cladding layer. Japanese Patent Application Laid-Open No. 6-51146 discloses an electron beam (EB). To change the refractive index of polyimide by irradiating the polyimide.

However, in such background art, (1) it takes a long time to manufacture an optical waveguide. The amount of change in the refractive index corresponds to the amount of irradiation of the electron beam, and long-time irradiation of the electron beam is required to obtain a large refractive index. (2) Since an electron beam is used, a high vacuum is required, and the apparatus is very large and expensive. (3) The whole processed sample must be in a high vacuum state. For this reason, the sample is limited to a size that matches the chamber size of the apparatus, and the workability and productivity are very poor. There is such an inconvenience.

From such a viewpoint, a method of forming a waveguide using a laser instead of an electron beam has been studied. If a laser beam can be used, a high vacuum such as an electron beam is not required, which is advantageous in terms of equipment and productivity. However, when an optical waveguide is formed using laser light, since the laser beam does not have uniform intensity (uniform energy) in the spot, there is an inconvenience that a streaky trace appears on a processing surface. is there. FIG. 1A shows an example of the intensity distribution in the laser beam spot BS during multi-mode oscillation. In this example, the intensity distribution changes in the form of horizontal stripes, and the regions PA to PD have relatively high intensity, and the regions PE to PH have relatively low intensity.

The present invention focuses on the above points,
It is an object of the present invention to provide a method for manufacturing an optical waveguide having high productivity and capable of performing processing with high accuracy even using a laser, and an apparatus therefor.

[0008]

In order to achieve the above object, the present invention is directed to a shape corresponding to a region where the intensity in a laser beam output from a laser means is uniform, and taking into consideration a processed shape of a waveguide. Provide a mask with a window formed
The waveguide is processed by a laser beam transmitted through the mask.

According to the present invention, the laser beam that has passed through the mask has a uniform intensity distribution. Therefore, processing is performed with high accuracy. Further, since the window of the mask is formed in consideration of the processing shape, a waveguide having a desired processing shape can be easily obtained.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0011]

Embodiments of the present invention will be described below in detail. First, the first embodiment will be described with reference to FIGS. FIG. 2 shows a state of processing the optical waveguide in the present embodiment. In FIG.
Laser light such as G or carbon dioxide gas output from a laser oscillator 10 enters a predetermined optical system 12, where optical processing such as beam shaping is performed. The processed laser beam is incident on the substrate 14 on which the optical waveguide is formed.

In this case, a mask 16 is provided at an appropriate position in the optical system 12. This mask 16
As shown in a plan view in FIG. 1B, a rectangular window 18 is formed, and the laser beam is transmitted through the window 18. Further, the window 18 is formed so as to be located within the intensity area PC of the beam spot BS shown in FIG. As described above, the area PC is an area having a relatively high intensity in the beam spot BS. Areas with high intensity include PA, PB, and PD. These areas have a narrow range.
Window 18 is set. Thus, the window 18 of the mask 16 is set in consideration of the intensity distribution of the laser beam. Therefore, the intensity distribution of the laser beam transmitted through the mask 16 is strong and uniform.

The substrate 14 is irradiated with such a laser beam. For this reason, as shown in FIG.
Is well processed in accordance with the beam shape, and a beautiful waveguide can be formed without causing inconvenience such as streaking on the processed surface. An appropriate material is buried (not shown) in the recess 20 of the substrate 14 thus processed, and a buried optical waveguide is manufactured.

Next, a second embodiment will be described with reference to FIGS. In this embodiment, as shown in FIG. 3A, the window 30 of the mask 16 is set to be circular in the area PC. For this reason, the laser beam spot also has a circular shape, and moves to process the substrate 14. In this case, the irradiation time of the laser beam differs depending on the position on the substrate 14. Accordingly, the cross section of the concave portion 32 of the substrate 14 processed by the laser beam has a spherical shape as shown in FIG.

This will be described with reference to FIG. 5. In the first embodiment, as shown by the arrow FA in FIG. 5A, a square beam spot BA is formed on the substrate 14 in the direction of forming the waveguide. Moving. Accordingly, the beam irradiation amount, that is, irradiation energy is equal between the beam center QA and the beam periphery QB, QC. Therefore, the processing depth is equal at any position of QA to QC, and becomes the concave portion 20 whose cross section is shown in FIG.

On the other hand, in Embodiment 2, FIG.
As shown by an arrow FB in FIG.
Moves on the substrate 14 in the waveguide forming direction. Therefore, the beam irradiation amount, that is, irradiation energy is different between the beam center QD and the beam periphery QE, QF. For this reason, the processing depth also differs depending on the position. That is, since the beam center QD has the largest beam irradiation amount,
Most deeply processed. Then, since the beam irradiation amount decreases as the beam periphery becomes QE and QF, the processing becomes gradually shallower. Therefore, the processing depth is as shown in FIG.
It becomes like the concave part 32 which shows a cross section in (B).

As described above, by changing the beam spot shape, the processed shape of the waveguide can be changed.

Next, a third embodiment will be described with reference to FIGS. In this embodiment, as shown in FIG. 4A, the window 40 of the mask 16 is set in a diamond shape in the area PC. Therefore, as shown in FIG. 5C, the laser beam spot BC also has a rhombic shape, and moves in the direction of the arrow FC to process the substrate 14. Also in this case, the irradiation amount of the laser beam differs depending on the positions QG to QI on the substrate 14. Therefore, the substrate 1 processed by the laser beam
The cross section of the recess 42 of FIG. 4 has a conical shape or a V-shaped cross section as shown in FIG. That is, the beam is processed deepest at the beam center QG, and is processed shallowly at the beam periphery QH and QI.

The present invention has a number of embodiments,
Various modifications can be made based on the above disclosure. For example, the following is also included. (1) In the above embodiment, a buried optical waveguide is manufactured by forming a concave portion on a substrate by a laser beam. However, if a waveguide layer is formed on the surface of the substrate and a part thereof is removed, a ridge type optical waveguide can be formed. Alternatively, a loaded optical waveguide can be obtained.

(2) Various shapes are conceivable as the window shape of the mask, and may be appropriately selected according to a desired processing shape. Further, a plurality of windows may be provided. It should be noted that by setting the window within a relatively weak area of the laser beam spot, a laser beam of uniform intensity can be obtained, but the energy at the corner is wasted and processing takes time. Become. (3) Various types of laser processing apparatuses such as a laser oscillator and an optical system are known, and any of them may be used. Known materials may also be used for the material of the substrate, the mask, and the like.

[0021]

As described above, the present invention has the following effects. (1) Since a laser beam having a uniform intensity is obtained by the mask, the optical waveguide can be processed with high productivity and high accuracy. (2) By changing the mask shape, the irradiation time of the laser beam changes and the shape in the depth direction also changes, so that the cross-sectional shape of the waveguide can be easily made into a desired shape, and the workability is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention. (A)
Is a diagram showing an example of the intensity distribution in the beam spot,
(B) is a diagram showing a mask shape, and (C) is a diagram showing a processed cross section.

FIG. 2 is a diagram showing a schematic device arrangement in the embodiment.

FIG. 3 is a diagram showing a second embodiment of the present invention. (A)
FIG. 3 is a view showing a mask shape, and FIG.

FIG. 4 is a diagram showing a third embodiment of the present invention. (A)
FIG. 3 is a view showing a mask shape, and FIG.

FIG. 5 is a plan view showing a state of processing in the embodiment. (A) is Embodiment 1, (B) is Embodiment 2,
(C) shows the third embodiment, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Laser oscillator 12 ... Optical system 14 ... Substrate 16 ... Mask 18, 30, 40 ... Window 20, 32, 42 ... Depression BA-BC, BS ... Beam spot PA-PD ... High intensity area PE-PH ... Intensity Weak area QA, QD, QG: Beam center position QB, QC, QE, QF, QH, QI: Beam peripheral position

Claims (2)

[Claims] 1. A manufacturing method of an optical waveguide for processing a waveguide by a laser beam output from a laser means, wherein the shape of the laser beam corresponds to a region where the intensity is uniform, and the processed shape of the waveguide is A method of manufacturing an optical waveguide, comprising: using a mask having a window formed in consideration of the above, and processing the waveguide by a laser beam transmitted through the mask. 2. An optical waveguide manufacturing apparatus for processing a waveguide with a laser beam output from a laser means, wherein the laser beam has a shape corresponding to a region where the intensity of the laser beam is uniform, and the processed shape of the waveguide. An optical waveguide manufacturing apparatus, comprising: a mask having a window formed in consideration of the above.