JP2003172836A - Optical waveguide element with optical path alternation function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide element which has a condensing function and transforms an optical path in which a problem of the contamination of an optical system is prevented without using such a means as a mechanical grinding and to provide a method of manufacturing the optical waveguide element. <P>SOLUTION: In the optical wave guide element, a resign block 5, which has the same refractive index as that of a core 2 of the optical waveguide, is formed at the light incident and emitting face of an optical waveguide and has a reflective face which alternates the optical path from the core. The resign block 5 is made contact with the end face of the core 2 which is interleaved between an upper clad 3 and a lower clad 1. The boundary face between the resign block 5 and air serves as a reflective face. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer optical waveguide, and more particularly, to a method for manufacturing an optical component such as an optical integrated circuit, an optical interconnection, or an optical multiplexer / demultiplexer. 2. Description of the Related Art As a base material of an optical component or an optical fiber, inorganic materials such as quartz glass and multi-component glass, which are characterized by a small light propagation loss and a wide transmission band, are widely used. However, recently, a polymer-based material has been developed, and has been attracting attention as a material for an optical waveguide since it is superior in workability and price as compared with an inorganic material. For example, a flat plate type having a core-cladding structure in which a polymer having excellent transparency such as polymethyl methacrylate (PMMA) or polystyrene is used as a core and a polymer having a lower refractive index than the core material is used as a cladding material. An optical waveguide has been manufactured (JP-A-3-188402). On the other hand, a flat optical waveguide with low loss has been realized using polyimide which is a transparent polymer having high heat resistance (Japanese Patent Laid-Open No. 2-110500). Due to demands such as cost, in the field of optical interconnection, surface emitting lasers (VC
SEL) is about to be mounted, but when laser light emitted perpendicular to the substrate enters an optical waveguide horizontal to the substrate, an optical path conversion of about 90 ° is required. The polymer optical waveguide is cut to about 45 ° by a dicing saw to enable 90 ° optical path conversion.
-300961). However, when cutting with a dicing saw, it cuts at 45 ° other than where it is needed, there is a risk of contamination at the time of cutting, and light does diverge because there is no condensing function by cutting alone, causing loss Problem. An object of the present invention is to prevent the optical system from being contaminated in order to avoid the above-mentioned problems without using a means such as mechanical grinding or the like, and to provide an optical path having a light collecting function. An object of the present invention is to provide an optical waveguide device capable of conversion and a method for manufacturing the same. As a result of intensive studies, the present inventor has found that the above-mentioned problems can be solved by dripping a very small amount of resin onto the end face of an optical waveguide, and has completed the present invention. That is, the present invention provides an optical waveguide, wherein a resin having a same refractive index as that of the core of the optical waveguide and having a reflection surface for converting an optical path from the core is formed on a light input / output end face of the optical waveguide. Element. Hereinafter, the present invention will be described in detail.
Here, a polyimide optical waveguide using a polyamic acid solution which is a precursor of polyimide will be described as an example,
Of course, it is also possible to produce the optical waveguide using a resin solution of an optical material other than the polyamic acid solution. In addition, the resin for optical path conversion will be described using a UV-curable epoxy acrylate as an example, but it is of course possible to produce a resin solution other than the UV-curable epoxy acrylate, a thermosetting resin solution, or the like. . First, a lower cladding layer is formed on a silicon wafer. A core layer is formed thereon. Next, a resist pattern is formed using a mask pattern on which a desired core pattern is drawn. Dry etching is performed by oxygen plasma using this resist as a mask. Next, the remaining resist is removed with a stripper. Next, an upper clad layer is formed from above. Next, the optical waveguide is peeled from the silicon wafer. If necessary, the optical waveguide film thus obtained is cut into a desired shape with a dicing saw or the like, and then, as shown in FIG. 1, a light emitting / receiving element 6 such as a laser diode or a photodetector is mounted and driven. An adhesive is attached to the circuit board 4 on which an electric circuit is formed. Thereafter, a very small amount of UV curable resin is dropped on the end of the optical waveguide by using an ink jet method or a dispensing method. Thereafter, the place where the liquid is dropped is irradiated with a UV lamp and cured to obtain a resin block 5. At this time, the resin block 5 is in contact with the end face of the core 2 sandwiched between the upper clad 3 and the lower clad 1. Then, the interface between the resin block 5 and air serves as a reflection surface. The reflecting surface has a curved surface due to surface tension before the resin is cured, and a light collecting effect can be obtained. In this manner, an optical waveguide having an optical path conversion function can be manufactured on an electric circuit board. With this structure, the light beam 7 is converted into an optical path, and at the same time, a light collecting effect is also generated. The circuit board 4 may use a transparent substrate,
A through hole may be provided at a location that becomes an optical path of light. In the case of a transparent substrate, the resin block 5 is formed so as to be in contact with a corresponding portion of the circuit board surface through which a light beam whose optical path is converted passes. When a through hole is provided in the circuit board, the resin block may have an interface with air at the through hole. It is more preferable that the through hole is filled with the resin of the resin block so that the resin comes into contact with the light receiving / emitting surface of the light receiving / emitting element because the reflection surface can be reduced and the loss can be suppressed. A reflection layer such as a metal layer may be provided on the interface between the resin block 5 and the air, which is the reflection surface. Subsequently, the present invention will be described in more detail with reference to several examples. It is clear that an unlimited number of polymer optical waveguides of the present invention can be obtained by using solutions of various polymers having different molecular structures. Therefore, the present invention is not limited to only these examples. Example 1 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2-bis (trifluoromethyl) -4 on a 4-inch silicon wafer After heating, a 15 wt% DMAc solution of polyamic acid of 4,4'-diaminobiphenyl (TFDB) was spin-coated so that the film thickness became 15 μm. This was heated and imidized at 380 ° C. for 1 hour to form a lower cladding layer. On top of this, 6FDA and 4,
Polyamide acid of 4'-oxydianiline (ODA) about 1
The film thickness is 50 μm after imidization of a 5 wt% DMAc solution by heating.
And imidized by heating. On top of this, a Si-containing resist was spin-coated so as to have a film thickness of 3 μm, and temporarily dried at 90 ° C. 50 μm width, length 6
Exposure and development were performed using a glass mask pattern on which 40 cm patterns were drawn, and resist patterning was performed. Next, the core layer was etched by 50 μm by reactive ion etching. Thereafter, the remaining resist was stripped with a stripping solution. Finally, the upper cladding layer 6
15 wt% DMAc of polyamic acid of FDA and TFDB
The solution was applied by a method such as spin coating, and this was heated and imidized to obtain an upper clad layer. In this way, a buried optical waveguide is formed. Thereafter, the optical waveguide on the silicon wafer was immersed in a 5 wt% hydrofluoric acid aqueous solution, and the optical waveguide was peeled off from the silicon wafer to produce a film optical waveguide. Next, a film optical waveguide was cut out to a width of 5 mm and a length of 5 cm using a dicing saw or the like. afterwards,
This optical waveguide film was adhered to an electric circuit board having a copper pattern formed on a commercially available polyimide film such as Kapton or Iupirex using an epoxy adhesive. By making these polyimide films thin, light can be substantially transmitted. Next, a UV-curable epoxy acrylate was dropped on the end surface of the 5-nanoliter optical waveguide by an inkjet method, and irradiated with a UV lamp at 200 mJ to be cured.
At that time, the contact angle between the electric circuit board and the dripping resin is 44 °
Met. In this manner, an optical waveguide device with an optical path conversion can be formed. At this time, the coupling efficiency between the optical waveguide and the laser diode and the coupling efficiency between the optical waveguide and the photodetector were about 80% and about 90%, respectively. Comparative Example 1 15 wt% DMA of polyamic acid of 6FDA and TFDB on a 4-inch silicon wafer
The solution c was spin-coated after heating so that the film thickness became 15 μm. After forming a lower clad layer by heat imidization, a polyamide acid solution of about 15 wt% of 6FDA and ODA as a core layer is spin-coated on the lower clad layer so as to have a film thickness of 50 μm after heat imidization. did. On top of this, a Si-containing resist was spin-coated so as to have a film thickness of 3 μm, and temporarily dried at 90 ° C. 50 μm
Exposure and development were performed using a glass mask pattern on which 40 patterns each having a width and a length of 6 cm were drawn, and resist patterning was performed. Next, the core layer was etched by 50 μm by reactive ion etching. Thereafter, the remaining resist was stripped with a stripping solution. Finally, 15 wt% of polyamic acid of 6FDA and TFDB to be the upper cladding layer
% DMAc solution by a method such as spin coating,
This was heated and imidized to obtain an upper cladding layer having a thickness of 15 μm. In this way, a buried optical waveguide is formed. After that, the optical waveguide on this silicon wafer is 5 wt.
% Of hydrofluoric acid aqueous solution, and the optical waveguide was peeled off from the silicon wafer to produce a film optical waveguide. Then width 5
A film optical waveguide was cut out to a length of 5 mm using a dicing saw or the like. Thereafter, this optical waveguide film was adhered to an electric circuit board having a copper pattern formed on a commercially available polyimide film such as Kapton or Iupirex using an epoxy adhesive. Next, the end face of the optical waveguide was cut by 45 ° using a dicing saw. At this time, the coupling efficiency between the optical waveguide and the laser diode and the coupling efficiency between the optical waveguide and the photodetector are about 50% and about 60%, respectively.
Met. According to the present invention, an optical waveguide and an optical component having good coupling efficiency with a light receiving / emitting element and excellent mass productivity can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an example of the configuration of a polymer optical waveguide having an optical path conversion function. [Description of References] 1: Lower clad, 2: Core, 3: Upper clad, 4:
Circuit board, 5: resin block, 6: light emitting / receiving element, 7: light beam

Claims (1)

Claims: 1. A resin having a reflection surface which is the same as that of a core of an optical waveguide and has a reflection surface for converting an optical path from the core is formed on a light input / output end face of the optical waveguide. Characteristic optical waveguide element.