JP2002277662A - Method for manufacturing optical waveguide coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polymer optical waveguide coupler which is easily manufactured with superior productivity and is easily connected with optical parts. SOLUTION: Waveguides with large core diameters or different core diameters and refractive indices are formed on a single substrate by using reactive oligomers having easy pattern forming performance, excellent heat resistance and moisture resistance, low birefringence and excellent formability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide coupler using a polymer material, and as various optical waveguide couplers used in the fields of optical communication and optical information processing, an optical integrated circuit or an optical wiring board. Etc. can be used.

[0002]

2. Description of the Related Art Conventionally, in the fields of optical communication and optical information processing, single-mode and multi-mode light processing is performed by using an optical fiber and a waveguide in each mode. In the fiber, the multi mode is used for LAN or factory wiring which is closed because of its large core diameter. On the other hand, the single mode has a large capacity and a high transmission rate, and is easily used for designing a waveguide. Recently, FTTH (Fibe
r To The Home) has been proposed and single and multi-mixed forms have come to be seen. For this reason, a component that can be used for both single and multi, a component that takes advantage of both, and an optical wiring board can be considered.

In waveguides, the refractive index difference and the core diameter may be different, and it is difficult to manufacture single and multi-cores simultaneously, and since they are used in different places, they are rarely used in a mixed form. Also, in a glass waveguide such as a quartz-based one, the core diameter is thick, or a different core diameter,
A waveguide having a refractive index is difficult to manufacture, and generally has many steps and is expensive, so that it is not often used for inexpensive optical waveguides, optical integrated circuits, optical wiring boards, and the like. On the other hand, the polymer material can support both single and multi. Further, a thin film can be easily formed by a spin coating method, a dip method, or the like, and is suitable for manufacturing a large-area optical waveguide. In addition, since a heat treatment step at a high temperature is not included in film formation, an advantage that an optical waveguide can be manufactured on a substrate that is difficult to heat at a high temperature, such as a semiconductor substrate or a plastic substrate, as compared with a case of using a glass material, is obtained. is there. Further, a flexible optical waveguide utilizing the flexibility and toughness of a polymer can be produced. Conventionally, polymer optical materials have been considered to have a problem in terms of environmental resistance such as heat resistance or moisture resistance, but recently, by including an aromatic group such as a benzene ring or by using an inorganic polymer. Materials with improved heat resistance have been reported [for example, JP-A-3-43423]. As described above, the polymer material has features in the formation of a thin film and a heat treatment step, and problems such as heat resistance and moisture resistance are being improved. As a method for producing a polymer waveguide, a photo-locking method or a selective photopolymerization method in which a monomer is included in a polymer and reacted with the monomer by light irradiation to produce a refractive index difference from a non-irradiated portion (Kurokawa et al., Applied Optics) 17, Vol. 646, 1978), application of methods used in semiconductor processing such as lithography and etching (Imamura et al., Electronics Letter, Vol. 27, p. 1342, 1991), methods using photosensitive polymers or resists (Trewela et al.,
SPIE 1177, p. 379, 1989). Among them, the last method has the highest simplicity and is excellent in productivity. However, since conventional photosensitive polymers are solid, the thicker the film, the greater the scattering in the ultraviolet and visible regions, the light transmission characteristics deteriorate, and especially the pattern reliability in the thick film is low, It has disadvantages such as poor resolution when cured and adversely affecting the loss of the waveguide to be manufactured. In addition, the waveguide loss is high because the reduction of the absorption loss and the like of the material is not considered with respect to the transparency, and the practicality of an optical component or the like manufactured using the material is insufficient. In order to eliminate the polarization dependence,
There is a drawback that the configuration of the optical device is actually considerably complicated because it is necessary to use it in combination with a polarizer or the like.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a method for forming an optical waveguide coupler pattern which has been made in view of the above-mentioned circumstances, and its object is to provide a simple pattern forming ability and excellent heat resistance and moisture resistance. It is an object of the present invention to provide a method for forming a polymer optical waveguide coupler pattern, which is characterized by using a reactive oligomer having low birefringence and excellent in processability, which is simple, has high productivity and is easily connected to an optical component. . In addition, by using a polymer material, a complicated process such as increasing the core diameter or manufacturing waveguides having different core diameters and refractive indexes on the same substrate can be performed. For example, when the same polymer material is used, when light passes through a crossing portion from a waveguide having a different core diameter, if there is almost no difference in the refractive index between the cores in this portion, the crossing portion is Since light passes through both waveguides, FIG. 3 is a conceptual diagram showing a light path in the waveguide of the present invention, and FIG. 4 is a sectional view and a plan view of the optical waveguide coupler of the present invention.
As shown in (1), light can be combined or branched from a waveguide having a small core diameter to a waveguide having a large core diameter. Also,
Since the refractive indices are different, waveguides having different confinement of light can be manufactured on the same substrate, and a waveguide in which a single waveguide and a multi-waveguide are mixed can be manufactured.

[0005]

The advantages of the photosensitive polymer material, which is a feature of the present invention, being a reactive oligomer are summarized below.

[0006] 1) Since the state before curing can improve the uniformity, it has excellent light transmission characteristics in the ultraviolet and visible regions, and has a sufficient resolution even when the cured film becomes thick.

2) Since the state before curing is an oligomer, even if there is a portion having irregularities, it can be flattened and permeate all over, so that it is easy to form a film corresponding to various shapes.

3) Since the oligomers are randomly linked and cured, the birefringence of the cured material can be reduced.

In order to achieve the object, a first aspect of the present invention is a method of manufacturing an optical waveguide coupler, comprising the steps of: forming a first waveguide having a first core diameter on the same substrate; Producing a second waveguide having a second core diameter different from the first core diameter and being coupled to the first waveguide.

According to a second aspect of the present invention, in a method of manufacturing an optical waveguide coupler, a step of manufacturing a first waveguide having a first core refractive index on the same substrate; Producing a second waveguide having a different second core refractive index and being coupled to the first waveguide.

According to a third aspect of the present invention, there is provided a method of manufacturing an optical waveguide coupler, comprising the steps of: forming a first waveguide having a first core refractive index and a first core diameter on the same substrate; Forming a second waveguide having a second refractive index different from the first refractive index and having a second core diameter different from the first core diameter and coupled to the first waveguide; It is characterized by the following.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an optical waveguide coupler according to any one of the first and third aspects, wherein the first core diameter and the second core diameter are at least in the longitudinal direction. Are characterized by different diameters.

According to a fifth aspect of the present invention, there is provided the method of manufacturing an optical waveguide coupler according to the first aspect, wherein the first polymer material is formed into a layer with a first thickness, and then lithographic means or resist is used. Forming a pattern of a first waveguide by one of means using reactive ion etching and a first core, and forming a second core on a substrate on which the first core is formed. After a molecular material is formed in a layer with a second thickness different from the first thickness, a pattern of a second waveguide is formed by one of lithography means and a means using resist and reactive ion etching. And manufacturing a second core.

[0014] A sixth aspect of the invention, the method for manufacturing an optical waveguide coupler, in the second embodiment, the first polymeric material having a refractive index upon curing becomes n ₁ is formed into a layer, lithography Forming a first core pattern by forming a pattern of a first waveguide by any one of means or a means using resist and reactive ion etching; and forming a first core on the substrate on which the first core is formed. The refractive index at the time of curing is n ₁
After forming a second polymer material having a different n ₂ from the layer shape, a pattern of the second waveguide is formed by one of lithography means or means using reactive ion etching with resist. And a step of manufacturing a core.

A seventh aspect of the present invention is an optical waveguide coupler.
In the third aspect of the manufacturing method, the refractive index at the time of curing
Is n₁The first polymer material to be formed into a layer with a first thickness
After forming, reactive with lithographic means or resist
Either of the means using ion etching
Forming a first waveguide pattern to form a first core,
On the substrate on which the first core is formed, a refractive index at the time of curing
Is the n₁N different from ₂The second polymer material that becomes
Forming a layer with a second thickness different from the first thickness,
Rough means or reactive ion etching with resist
Patterning the second waveguide by one of the means used
And forming a second core by forming the second core.

According to an eighth aspect of the present invention, there is provided a method for manufacturing an optical waveguide coupler according to the fifth to seventh aspects, wherein
The first polymer material and / or the second polymer material are transparent and photosensitive.

According to a ninth aspect of the present invention, there is provided a method of manufacturing an optical waveguide coupler according to the fifth to eighth aspects, wherein
The first polymer material and / or the second polymer material are made of a photosensitive polyamic acid or are made of an epoxy-based or acrylic-based or silicone-based oligomer or monomer.

According to a tenth aspect of the present invention, in the method for manufacturing an optical waveguide coupler, in the ninth aspect, the first polymer material and / or the second polymer material is represented by the formula (1).

[0019]

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(Wherein R ₁ is a tetravalent group of bisalkylbenzene or bisperfluoroalkylbenzene,
R ₃ is selected from the group consisting of an alkyl group, a fluoroalkyl group, and a phenyl group; R ₂ is an alkylene group;
(Selected from the group consisting of an alkylphenylene group and a perfluorophenylene group).

According to an eleventh aspect of the present invention, in the method for manufacturing an optical waveguide coupler, in the ninth aspect, the first polymer material and / or the second polymer material is represented by formula (2).

[0022]

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(Wherein R ₁ and R ₂ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkyl group, an alkoxy group and a trifluoromethyl group, and X ₁ , X ₂ and X ₃ Is independently a linking group selected from the group consisting of a C ₁ -C ₃ alkylene group, an oxyalkylene group and an alkyleneoxy group, and Y is an epoxy group or

[0024]

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Is produced from the epoxy oligomer represented by the formula (1).

According to a twelfth aspect of the present invention, in the method for manufacturing an optical waveguide coupler, in the ninth aspect, the first polymer material and / or the second polymer material is represented by the formula (3)

[0027]

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(Wherein R ₁ and R ₂ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkyl group, an alkoxy group and a trifluoromethyl group, and X ₁ , X ₂ and X ₃ alkylene group of C ₁ -C ₃ are each independently, a linking group selected from the group consisting of oxyalkylene groups and alkylene group, the acrylic oligomer or monomer Y is represented by an acrylic group or a methacrylic group) It is characterized by being manufactured from.

According to a thirteenth aspect of the present invention, in the method of manufacturing an optical waveguide coupler, in the ninth aspect, the first polymer material and / or the second polymer material is represented by formula (4).

[0030]

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(Wherein, X represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, an alkoxy group, and m represents 1 to
Represents an integer of 4. x and y indicate the existence ratio of each unit, and neither x nor y is 0. R ₁ and R ₂ are
Methyl group, ethyl group, isopropyl group, _{R 1} and R
₂ may be the same), or a silicone-based oligomer or monomer represented by the formula:

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of manufacturing an optical waveguide coupler comprising a waveguide having two or more cores according to the present invention, a core is manufactured by applying a photosensitive polymer material and forming a mask having a waveguide pattern. A method of irradiating with UV light, patterning by lithography (referred to as lithography means in this specification), applying and curing a photosensitive polymer material, applying a silicon-containing resist thereon,
A method of irradiating with a UV light through a mask having a waveguide pattern, hardening, forming a pattern groove by reactive ion etching with oxygen, and removing a silicon-containing resist (in this specification, a method using resist and reactive ion etching) ) Can be combined. Thus, it is possible to manufacture an optical waveguide coupler including waveguides having different core diameters and / or different refractive indexes on the same substrate.

In the present specification, the direction in which the core diameter depends on the film thickness to be applied is referred to as “vertical direction”, and the direction depending on the slit width of the mask is referred to as “lateral direction”.

In the optical waveguide coupler of the present invention, the first core diameter and the second core diameter of the waveguide can be different both in the vertical direction and the horizontal direction, but at least in the vertical direction. is there.

When the diameters of the cores in the longitudinal direction are different, the first polymer layer for applying the first polymer material for the first core diameter and the second polymer material for the second core diameter are used. Regarding the thickness of the second layer in the case of application, it is preferable to make the first layer produced earlier thinner than the second layer, because unevenness when applying the second layer is reduced. Preferred, but not limited to.

Generally, one of the two core diameters is 1 μm to 1 μm.
Preferably, 0 μm and the other is 3 μm to 100 μm.

The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0038]

EXAMPLES Example 1 A liquid epoxy oligomer having a variable refractive index having the following structural formula and a photopolymerization initiator 2
Solution 1 in which wt% was adjusted was prepared.

[0039]

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An example of a method for manufacturing an optical waveguide according to the present invention will be described with reference to FIGS.

First, as shown in FIG.
An epoxy resin, which is a photosensitive polymer material mainly composed of the solution 1, was applied to the i-substrate 10 to a desired thickness by spin coating so that the refractive index at the time of light curing was 1.52 at a wavelength of 0.85 μm. . Next, after irradiation with UV light to produce the lower cladding 11, the refractive index at the time of curing has a wavelength of 0.8.
An epoxy resin, which is the photosensitive polymer material 12 for the first layer of the core, containing the solution 1 as a main component and having a thickness of 6 μm was applied so that the thickness was 5 μm and 1.535.

Next, as shown in (b), UV light 14 was irradiated through a mask 13 having a waveguide pattern 13a. The irradiation amount was 2000 mJ / cm ² . afterwards,
When this sample was developed with an isopropanol solution, the liquid epoxy oligomer was cured only in the light-irradiated portion according to the ridge pattern of the mask, and a ridge pattern of the core 16 could be produced.

Next, as shown in (c), an epoxy which is a photosensitive polymer material for the second core layer having the same refractive index (1.535 at a wavelength of 0.85 μm) as that for the first core layer. Resin 15 was applied to a thickness of 50 μm.

Next, as shown in (d), a mask 17 having a pattern 17a crossing the ridge pattern was used, and UV light 14 was irradiated through the mask 17.
Similarly, when developed with an isopropanol solution, the liquid epoxy oligomer was cured only in the light-irradiated portion according to the ridge pattern of the mask, and a ridge pattern of the core 18 as shown in FIG. A cross-sectional view is shown).

Thereafter, as shown in (f), the ridge pattern has a refractive index of 1.15 at a wavelength of 0.85 μm during photocuring.
An epoxy resin for cladding containing solution 1 as a main component was applied and cured so as to obtain an optical waveguide coupler of 52.

(Embodiment 2) An example of a method for manufacturing an optical waveguide of the present invention will be described with reference to FIGS.

First, as shown in FIG.
An epoxy resin, which is a photosensitive polymer material containing Solution 1 as a main component, was applied to an i-substrate 20 by spin coating so that the refractive index at the time of photocuring was 1.52 at a wavelength of 0.85 μm. . Next, the lower clad 21 was produced by irradiation with UV light. Furthermore, an epoxy resin for the first layer of the core having the solution 1 as a main component has a thickness of 6 μm so that the refractive index upon curing becomes 1.535 at a wavelength of 0.85 μm.
m, and a silicon-containing resist 23 is applied to the resin film 22 cured by irradiating UV light, and the UV light 2 is applied through a mask 25 having a waveguide pattern 25a.
4 were irradiated.

Next, as shown in (b), when this sample was developed with a developing solution of the main material tetramethylammonium, a residual image of the silicon-containing resist could be left only in the non-irradiated portion according to the ridge pattern of the mask. As shown in (c), a pattern groove was formed by reactive ion etching 26 using oxygen, and a ridge pattern of an epoxy oligomer resin was formed according to the ridge pattern surface of the silicon-containing resist.

Next, as shown in (d), after removing the silicon-containing resist, a second core layer having the same refractive index (1.535 at a wavelength of 0.85 μm) as the first core layer is used. Epoxy resin 27, which is a photosensitive polymer material, was applied to a thickness of 50 μm.

Next, as shown in (e), UV light 24 was irradiated through a mask 28 having a waveguide pattern 28a crossing the ridge pattern. The irradiation dose is 20
It was 00 mJ / cm ² .

Thereafter, as shown in (f), when this sample was developed with an isopropanol solution, the liquid epoxy oligomer was hardened only in the light-irradiated portion according to the ridge pattern of the mask, and a ridge pattern of the core 29 was produced. . Next, the cladding epoxy resin 30 containing the solution 1 as a main component is applied and cured on the ridge pattern so that the refractive index at the time of light curing becomes 1.52 at a wavelength of 0.85 μm.
An optical waveguide coupler was manufactured.

(Example 3) By a method similar to that of Example 1, a 4-inch Si substrate having a refractive index at the time of photocuring at a wavelength of 0.1 was used.
An epoxy resin prepared from Solution 1 so as to have a thickness of 85 μm and 1.52 was applied by spin coating to a desired thickness, and was irradiated with UV light to produce a lower clad. Next, an epoxy resin for the first layer of the core containing solution 1 as a main component is applied so that the refractive index at the time of curing becomes 1.535 at a wavelength of 0.85 μm, and UV light is applied through a mask having a waveguide pattern. Was irradiated. The irradiation amount was 2000 mJ / cm ² . Thereafter, when this sample was developed with an isopropanol solution, the liquid epoxy oligomer was cured only in the light-irradiated portion according to the ridge pattern of the mask, and a ridge pattern of the core could be produced.

Next, an epoxy resin for the second core layer having the same refractive index (1.535 at a wavelength of 0.85 μm) as that for the first core layer prepared from the solution 1 is applied and irradiated with UV light. Further, a silicon-containing resist was applied, and a mask having a pattern crossing the ridge pattern was used, and UV light was irradiated through the mask. Thereafter, when this sample was developed with a developing solution of tetramethylammonium as a main material, a residual image of a silicon-containing resist could be left only in an unirradiated portion according to a ridge pattern of a mask. A pattern groove was formed by reactive ion etching using oxygen, and a ridge pattern of an epoxy oligomer resin was formed according to the ridge pattern surface of the silicon-containing resist.

Next, the silicon-containing resist is removed,
This ridge pattern has a refractive index of 0.85 at the time of photocuring.
An epoxy resin containing Solution 1 as a main component was applied so as to have a thickness of 1.52 μm, and cured, thereby producing an optical waveguide coupler.

That is, by modifying the process of the second embodiment, the first core layer is formed by applying an epoxy resin, irradiating UV light through a mask having a waveguide pattern, and performing lithography and patterning. Then, apply epoxy resin and cure, apply a silicon-containing resist on it,
An afterimage was irradiated by irradiating UV light through a mask having a waveguide pattern, a pattern groove was formed by reactive ion etching, and a second core layer was formed by a method of removing a silicon-containing resist, thereby manufacturing an optical waveguide coupler.

Since the order of the steps of the first core layer and the second core layer in FIG. 2 is simply reversed, the drawing is omitted.

(Example 4) In the same manner as in Example 1, a 4-inch Si substrate had a refractive index at the time of photocuring at a wavelength of 0.3.
An epoxy resin prepared from Solution 1 so as to have a thickness of 85 μm and 1.52 was applied by spin coating to a desired thickness, and was irradiated with UV light to produce a lower clad. Next, an epoxy resin for the first layer of the core containing solution 1 as a main component is applied so that the refractive index at the time of curing becomes 1.535 at a wavelength of 0.85 μm, irradiated with UV light, and further coated with a silicon-containing resist. U through a mask having a waveguide pattern
V light was applied. Thereafter, when this sample was developed with a developing solution of tetramethylammonium as a main material, a residual image of a silicon-containing resist could be left only in an unirradiated portion according to a ridge pattern of a mask. A pattern groove was formed by reactive ion etching of oxygen, and a ridge pattern of an epoxy oligomer resin was formed according to the ridge pattern surface of the silicon-containing resist.

Next, the silicon-containing resist was removed, and an epoxy resin for the second core having the same refractive index (1.535 at a wavelength of 0.85 μm) as that for the first core prepared from Solution 1 was applied. UV light was applied, a silicon-containing resist was applied, and UV light was applied through a mask having a waveguide pattern. Thereafter, when this sample was developed with a developing solution of tetramethylammonium as a main raw material, a liquid silicon-containing resist was left only in an unirradiated portion according to the ridge pattern of the mask. A pattern groove was formed by reactive ion etching using oxygen, and a ridge pattern of an epoxy oligomer resin was formed according to the ridge pattern surface of the silicon-containing resist.

Next, the silicon-containing resist is removed,
This ridge pattern has a refractive index of 0.85 at the time of photocuring.
An epoxy resin containing Solution 1 as a main component was applied so as to have a thickness of 1.52 μm, and cured, thereby producing an optical waveguide coupler.

That is, the process of the second embodiment is changed to apply and cure an epoxy resin, apply a silicon-containing resist thereon, and apply UV through a mask having a waveguide pattern.
After curing by irradiation with light, a pattern groove is formed by reactive ion etching with oxygen, the first layer of the core is formed by removing the silicon-containing resist, and then the second layer of the core is formed by the same method. A waveguide coupler was manufactured. FIG.
The process of the first core layer is applied to the second core layer, and the same method is repeated.

(Example 5) The refractive index at the time of curing has a wavelength of 0.8.
Example 1 except that an epoxy resin containing Solution 1 as a main component was used as the first layer of the core so that 1.525 at 5 μm.
By the same method as described above, optical waveguide couplers having different relative refractive index differences of the cores were manufactured.

(Example 6) The refractive index at the time of curing was 0.8 wavelength.
Example 2 except that an epoxy resin containing Solution 1 as a main component was used as the first layer of the core so that 1.525 at 5 μm.
By the same method as described above, optical waveguide couplers having different relative refractive index differences of the cores were manufactured.

(Example 7) The refractive index at the time of curing has a wavelength of 0.8.
Example 3 except that an epoxy resin containing Solution 1 as a main component was used as the first layer of the core so that the thickness became 1.525 at 5 μm.
By the same method as described above, optical waveguide couplers having different relative refractive index differences of the cores were manufactured.

(Embodiment 8) The refractive index at the time of curing has a wavelength of 0.8.
Example 4 except that an epoxy resin containing Solution 1 as a main component was used as the first layer of the core so as to obtain 1.525 at 5 μm.
By the same method as described above, optical waveguide couplers having different relative refractive index differences of the cores were manufactured.

The following table summarizes the patterning method and the refractive index for performing the two-layer core manufacturing process used in the above examples.

[0066]

[Table 1]

[0067]

[Table 2]

By taking the refractive index of the core as in Examples 5 to 8, the core 1 can be brought closer to the single mode condition, and the core 2 can be handled like a multimode. A waveguide in which mode and multi-mode are mixed can be manufactured.

Example 9 An optical waveguide coupler was produced in the same manner as in Example 1, using a solution prepared by adjusting a liquid silicone epoxy oligomer represented by the following structural formula and 2 wt% of a photopolymerization initiator.

The optical waveguide coupler was cut into a length of 5 cm by a dicing saw, and the insertion loss was measured. The loss was 1.5 dB or less at 1.3 μm and 3.0 dB or less at a wavelength of 1.55 μm. The polarization dependence of the insertion loss is 0.1 dB at both 1.3 μm and 1.55 μm.
It was below. Further, the loss of this optical waveguide coupler is 75
It did not fluctuate for more than one month under the conditions of ° C / 90% RH.

[0071]

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Example 10 An optical waveguide coupler was manufactured in the same manner as in Example 1, except that a solution prepared by adjusting a liquid silicone oligomer represented by the following structural formula and a photopolymerization initiator at 2 wt% was used. This optical waveguide coupler was cut out to a length of 5 cm by a dicing saw, and the insertion loss was measured.
It was 3.0 dB or less in μm. In addition, the polarization dependence of the insertion loss is equal to 0.3 at both 1.3 μm and 1.55 μm.
It was 1 dB or less. Further, the loss of this optical waveguide coupler did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.

[0073]

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(Example 11) In the same manner as in Example 1, a solution prepared by adjusting a liquid silicone vinyl ether oligomer represented by the following structural formula and 2 wt% of a photopolymerization initiator was used. An optical waveguide coupler was manufactured. This optical waveguide coupler was cut out to a length of 5 cm with a dicing saw, and the insertion loss was measured.
1.0 dB or less at a wavelength of 0.85 μm and 0.3 at 1.3 μm.
It was 5 dB or less and 1.0 dB or less at a wavelength of 1.55 μm. The polarization dependence of the insertion loss was 0.1 dB or less. Further, the loss of this optical waveguide coupler is 75 ° C./90.
It did not fluctuate for more than one month even under the condition of% RH.

[0075]

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(Example 12) A solution prepared by adjusting a liquid acrylic oligomer having the following structural formula and 2 wt% of a photopolymerization initiator was prepared.

[0077]

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Next, an optical waveguide coupler was manufactured in the same manner as in Examples 1 to 8.

It should be noted that even if the liquid acrylic oligomer of the present invention was used instead of the liquid epoxy oligomer of Examples 1 to 8, parts having the same performance as those of Examples 9 to 11 could be produced.

Example 13 A solution was prepared in which a polyamic acid having the structural formula shown below and 2 wt% of a photopolymerization initiator were prepared.

[0081]

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Next, an optical waveguide coupler was manufactured in the same manner as in Examples 1 to 8.

In addition, even when the polyamic acid of the present invention was used in place of the liquid epoxy oligomer of Examples 1 to 8, parts having the same performance as those of Examples 9 to 12 could be produced.

As described in the above embodiments, the present invention relates to a method of patterning by applying a photosensitive polymer material in a core forming step, irradiating UV light through a mask having a waveguide pattern, and performing lithography. Apply and cure an epoxy resin, apply a silicon-containing resist on it, irradiate it with UV light through a mask having a waveguide pattern, cure it, and form a pattern groove by reactive ion etching with oxygen. 2 of the way to get rid of
By combining the types, an optical waveguide composed of waveguides having different core diameters or different refractive indexes can be manufactured on the same substrate.

When the core is formed as the third layer and the fourth layer, the number of manufacturing steps is increased, so that the pattern accuracy is lowered and the pattern is deteriorated by lithography or the like. However, it was confirmed that the pattern was formed.

[0086]

As described above, the present invention has the following effects. (1) Simple and highly productive, characterized by using a reactive oligomer having a simple pattern-forming ability, excellent heat resistance and moisture resistance, low birefringence, and excellent workability, and excellent connection with optical components. A polymer optical waveguide coupler that can be easily manufactured can be manufactured. (2) In addition, a waveguide having a large core diameter or different core diameters and refractive indexes can be manufactured on the same substrate. Thus, a waveguide in which a single waveguide and a multi-waveguide are mixed can be manufactured.

[Brief description of the drawings]

1 (a) to 1 (f) are schematic views showing respective steps in producing an embodiment of an optical waveguide coupler of the present invention.

FIGS. 2A to 2F are schematic views showing each step in the case of manufacturing an embodiment of the optical waveguide coupler of the present invention.

FIG. 3 is a conceptual diagram illustrating a light path in a waveguide according to the present invention.

FIG. 4 is a sectional view and a plan view of the optical waveguide coupler of the present invention.

[Explanation of symbols]

 Reference Signs List 10 substrate 11 clad 12 photosensitive material 13 mask 14 UV light 15 photosensitive material 16 core 17 mask 18 core 19 clad 20 substrate 21 clad 22 UV-cured resin film for core 23 resist 24 UV light 25 mask 26 reactive ion etching 27 Photosensitive material 28 Mask 29 Core 30 Clad

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 6/12 G02B 6/12 N (72) Inventor Saburo Imamura 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo No.NTT Advanced Technology Co., Ltd. (72) Inventor Akira Tomaru 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inventor Makoto Hikita Within NTT Advanced Technology Co., Ltd. 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Kazuko Hashimoto 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo・ TTI Advance Technology Co., Ltd. (72) Inventor Atsushi Yamauchi 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo NTT Inside Advanced Technology Co., Ltd. (72) Inventor Ayako Sakuma 2-1-1 Nishi Shinjuku, Shinjuku-ku, Tokyo NTT Advanced Technology Co., Ltd. (72) Inventor Masayuki Doguchi Shinjuku-ku, Tokyo (1-1) Nishi Shinjuku 2-1-1 NTT Advanced Technology Co., Ltd. (72) Inventor Chie Tomiyoshi 2-1-1 Nishi Shinjuku, Shinjuku-ku, Tokyo NTT Advanced Technology Co., Ltd. F term in the formula company (reference) 2H047 KA04 LA12 PA01 PA21 PA24 PA28 QA05 TA21 TA43 4J035 BA04 CA01U CA04U CA041 LB20 4J036 AC01 AC09 AC11 AD01 HA02 JA08 KA01 4J043 PA02 PC075 QB31 QB61 RA05 ZB21 4J100 CA66P

Claims (13)

[Claims] A first core having a first core diameter on the same substrate;
Forming a second waveguide having a second core diameter different from the first core diameter and coupling with the first waveguide.
And a step of manufacturing the optical waveguide. 2. A step of manufacturing a first waveguide having a first core refractive index on the same substrate; and forming the first waveguide having a second core refractive index different from the first refractive index. Producing a second waveguide to be coupled with the waveguide. 3. A step of manufacturing a first waveguide having a first core refractive index and a first core diameter on the same substrate, wherein the first waveguide has a second refractive index different from the first refractive index. First
A method of manufacturing a second waveguide having a second core diameter different from that of the first waveguide and coupling to the first waveguide. 4. The method of manufacturing an optical waveguide coupler according to claim 1, wherein the first core diameter and the second core diameter are different at least in a vertical direction. 5. After forming a first polymer material in a layer with a first thickness, a pattern of a first waveguide is formed by one of lithography means and a means using resist and reactive ion etching. Forming a first core by forming a second polymer material on the substrate on which the first core is formed in a second film thickness different from the first film thickness. Forming a second core pattern by forming a pattern of a second waveguide by one of lithography means and a means using a resist and reactive ion etching. The manufacturing method of the optical waveguide coupler of the above. 6. A refractive index upon curing is first made to n ₁ polymer material is formed into a layer, the first waveguide by either means of using a reactive ion etching lithography unit or resist a step of preparing a first core to form a pattern, the first core is formed onto a substrate that, the refractive index upon curing becomes the n ₁ is different from n ₂ 2
Forming a second core pattern by forming either one of lithography means or means using resist and reactive ion etching after forming the polymer material in a layered form. 3. The method of manufacturing an optical waveguide coupler according to claim 2, wherein: After 7. refractive index upon curing to form a layer of the first polymeric material to become n ₁ in the first film thickness, whereas any means using reactive ion etching and lithography unit or resist a step of forming a pattern of the first waveguide to produce a first core arrangement, the first core formed on the substrate, the refractive index upon curing becomes the n ₁ is different from n ₂ A second polymer material is formed in a layer with a second film thickness different from the first film thickness, and the pattern of the second waveguide is formed by either lithography means or means using resist and reactive ion etching. Forming a second core by forming the second core. 4. The method of manufacturing an optical waveguide coupler according to claim 3, further comprising: 8. The optical waveguide coupler according to claim 5, wherein the first polymer material and / or the second polymer material are transparent and have photosensitivity. Manufacturing method. 9. The method according to claim 1, wherein the first polymer material and / or the second polymer material is made from a photosensitive polyamic acid;
The method of manufacturing an optical waveguide coupler according to any one of claims 5 to 8, wherein the optical waveguide coupler is manufactured from an epoxy-based, acrylic-based, or silicone-based oligomer or monomer. 10. The first polymer material and / or the second polymer material.
Is a polymer material of the formula (1) (Wherein, R ₁ is a tetravalent group of bisalkylbenzene or bisperfluoroalkylbenzene, R ₃ is selected from the group consisting of an alkyl group, a fluoroalkyl group, and a phenyl group, and R ₂ is an alkylene group, an alkylphenylene The method for producing an optical waveguide coupler according to claim 9, wherein the optical waveguide coupler is made of a polyamic acid represented by the following formula: 11. The first polymer material and / or the second polymer material.
Is a polymer material of the formula (2) (Wherein, R ₁ and R ₂ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group and a trifluoromethyl group, and X ₁ , X ₂ and X ₃ are each independently C ₁ A linking group selected from the group consisting of an alkylene group, an oxyalkylene group and an alkyleneoxy group of C ₃ to C ₃ , wherein Y is an epoxy group or 10. The method of manufacturing an optical waveguide coupler according to claim 9, wherein the optical waveguide coupler is produced from an epoxy-based oligomer or monomer represented by the following formula: 12. The first polymer material and / or the second polymer material.
Is a polymer material of the formula (3) (Wherein, R ₁ and R ₂ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group and a trifluoromethyl group, and X ₁ , X ₂ and X ₃ are each independently C ₁ alkylene group -C _3, a linking group selected from the group consisting of oxyalkylene groups and alkylene group, Y is to be produced from the acrylic oligomer or monomer represented by a is) acrylic group or methacrylic group The method for manufacturing an optical waveguide coupler according to claim 9, wherein: 13. The first polymer material and / or the second polymer material.
Is a polymer material of the formula (4) (In the formula, X represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, or an alkoxy group, m represents an integer of 1 to 4. x and y represent the abundance ratio of each unit. R ₁ and R ₂ represent a methyl group, an ethyl group, or an isopropyl group, and R ₁ and R ₂ may be the same.) The method for manufacturing an optical waveguide coupler according to claim 9, wherein: