JP3571482B2 - Method for forming polymer optical waveguide pattern for aperture conversion - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is applicable to various optical waveguides, optical integrated circuits, optical wiring boards, and the like used in general optical fields, micro-optical fields, optical communication fields, optical information fields, and the like. The present invention relates to a method of manufacturing a waveguide, and more particularly to a method of forming a polymer optical waveguide pattern for diameter conversion, which is excellent in mass productivity and is easily connected to optical components.
[0002]
[Prior art]
Conventionally, it has been known that a polymer material is easy to form a thin film by a spin coating method, a dip method, or the like, and is suitable for producing a large-area optical waveguide. In addition, since the method of manufacturing an optical waveguide using such a polymer material does not include a heat treatment step at a high temperature when forming a film, a semiconductor substrate or a plastic substrate is compared with a case where an inorganic glass material such as quartz is used. For example, there is an advantage that an optical waveguide can be manufactured on a substrate on which heat treatment at a high temperature is difficult. Furthermore, it is also possible to produce a flexible optical waveguide utilizing the properties of a polymer, for example, flexibility and toughness. For these reasons, it is expected that optical waveguide components such as optical integrated circuits used in the field of optical communication and optical wiring boards used in the field of optical information processing will be manufactured in large quantities and at low cost using polymer optical materials. Have been.
[0003]
Conventionally, polymer optical materials have been problematic in terms of environmental resistance such as heat resistance or moisture resistance. However, in recent years, there has been reported a material in which the heat resistance is improved by including an aromatic group such as a benzene ring or by using an inorganic polymer (for example, JP-A-3-43423). In addition, the polymer material is characterized by the thin film formation and the heat treatment process as described above, and problems such as heat resistance and moisture resistance are being improved.
[0004]
The following method is known as a known method for producing a polymer waveguide. That is, a photo-locking or 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, Vol. 17, p. 646, 1978) ), Application of methods used in semiconductor processing such as lithography and etching (Imamura et al., Electronics Letter, Vol. 27, pp. 1342, 1991), and methods using photopolymers or resists (Trewela et al., SPIE 1177, pp. 397, 1989). Year). Among these methods, the method with the highest simplicity and excellent mass productivity is Treweller's method (a method using a photosensitive polymer or a resist).
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional method, since a material made of a polymer is used as the photosensitive material, the problem to be solved, that is, low pattern reliability particularly in a thick film, and transparency are not considered. There is a problem to be solved that the waveguide loss is high. Therefore, an optical component or the like manufactured using the material has an insufficient aspect in practical use. In addition, a material containing an aromatic group such as a benzene ring has another problem to be solved in that the birefringence is large in order to increase heat resistance. That is, when a polymer thin film is formed using such a material, the molecular chain, particularly an aromatic group such as a benzene ring, distributes light within the thin film to exhibit optical anisotropy. Therefore, an optical waveguide or the like manufactured using the material has polarization dependency, and even if the intensity of incident light is constant, its output characteristics fluctuate due to fluctuations in the polarization plane. In particular, a problem arises when the waveguide is actually used as a single-mode waveguide. In order to eliminate such polarization dependence, it is necessary to use the optical device in combination with a polarizer or the like. As a result, the configuration of the optical device becomes considerably complicated, which is not preferable in practical use.
[0006]
In order to put the optical device into practical use, economical efficiency is important, but generally, connecting an optical waveguide to an optical fiber, a light emitting element, or a light receiving element is a major factor of cost. This is because conventional connections require a lens system to be inserted between the connecting parts in order to match the dimensions of the mode fields, which differ greatly from each other, and to finely align and fix them so that their optical axes coincide. is there. However, in this case, a lens system is required, the assembling work is complicated, and both material and processing costs are high. Attempts have been made to match the shape and size of the mode field by waveguide processing, but control in the lateral direction is possible but control in the thickness direction is very difficult.
[0007]
However, the present invention has been made in view of such a current situation, and an object of the present invention is to solve the above-mentioned problems, to provide a simple pattern forming ability and excellent heat resistance and moisture resistance, small birefringence, and workability. Provided is a method for forming a polymer optical waveguide pattern for diameter conversion, which is characterized by using a photosensitive oligomer, a photosensitive film, and a liquid photosensitive oligomer which are excellent in simplicity, excellent in mass productivity, and easily connected to an optical component. Is to do.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for forming a polymer optical waveguide pattern for diameter conversion according to the present invention comprises a step of preparing a liquid storage pool, a liquid photosensitive liquid containing a photosensitive oligomer and a photopolymerization initiator in the liquid storage pool. Step of filling the photosensitive material, by irradiating light directly through a mask or a predetermined portion of the photosensitive material, along the longitudinal directionWidthForming a continuously changing pattern latent image, and at least including removing a portion of the photosensitive material that has not been subjected to the light irradiation with a solvent,Continuously changing the light intensity of the light irradiation,The predetermined portion on which the pattern latent image is formed constitutes the core portion of the optical waveguide, the bottom of the liquid storage pool constitutes the lower cladding of the optical waveguide, and the photosensitive oligomer is an epoxy oligomer, liquid silicone epoxy described later. It is selected from the group consisting of oligomers, liquid silicone oligomers, liquid silicone vinyl ether oligomers, and acrylic oligomers.
[0009]
In the method of forming a polymer optical waveguide pattern for diameter conversion,The liquid storage pool has grooves for aligning and arranging an optical fiber and / or a micro-optical element on both sides of the optical waveguide facing in the longitudinal direction. By arranging the optical fiber and / or the micro-optical element in this groove, the core is optically connected to the optical fiber and / or the micro-optical element. Preferably, the design optical element is selected from the group consisting of a laser diode (LD), a light emitting diode (LED), and a light receiving diode (PD).
[0010]
Further, as another embodiment, in the method for forming a polymer optical waveguide pattern for diameter conversion,The liquid pool has a depth gradient whose bottom continuously changes along the longitudinal direction of the optical waveguide.
[0011]
Preferably, the photosensitive substance comprises a photosensitive oligomer and a photopolymerization initiator.
[0012]
Further preferably, the photosensitive oligomer may be any of the following compounds. That is, the general formula (1)
[0013]
Embedded image
[0014]
(Where R₁  , R₂  Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a trifluoromethyl group;₁  , X₂  , X₃  Represents an alkyl group, an alkyl ether group, a linking group containing an aromatic ring and containing at least one OH group, and Y is
[0015]
Embedded image
[0016]
Or
[0017]
Embedded image
[0018]
Represents a polymerization active group. )
An epoxy oligomer represented by the formula:
General formula (2)
[0019]
Embedded image
[0020]
(Wherein, 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. Z represents an epoxy group represented by the following formula (I) or (II)) ,
[0021]
Embedded image
[0022]
Embedded image
[0023]
x and y indicate the proportion of each unit, and y may be smaller than x and may be 0);
General formula (3)
[0024]
Embedded image
[0025]
(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. It cannot be 0. R₁  , R₂  Represents a methyl group, an ethyl group, or an isopropyl group;₁  And R₂  Liquid silicone oligomers represented by the following formulas:
General formula (4)
[0026]
Embedded image
[0027]
(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 show the proportion of each unit. R represents a methyl group, an ethyl group, or an isopropyl group), or a liquid silicone vinyl ether oligomer represented by the formula:
General formula (5)
[0028]
Embedded image
[0029]
(Where R₁  , R₂  Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a trifluoromethyl group;₁  , X₂  , X₃  Represents an linking group containing an alkyl group, an alkyl ether group and an aromatic ring, and Y is
[0030]
Embedded image
[0031]
Or
[0032]
Embedded image
[0033]
Represents a polymerization active group. ) Is an acrylic oligomer.
[0034]
The present inventors have proposed that these photosensitive materials have a simple pattern-forming ability, are excellent in heat resistance and moisture resistance, have small birefringence, and are easily connected to optical components. The inventors have found that an optical waveguide pattern can be formed, and have completed the present invention.
[0035]
That is, in the present invention, a waveguide pattern having steep and smooth wall surfaces can be formed by curing the film by light irradiation and developing it with an appropriate solvent as in the case of a negative resist used in LSI processing or the like. Further, by forming a liquid pool with controlled irradiation amount or depth, control in the thickness direction became possible. In addition, conventional polymers are very difficult to form thick films and process waveguides, whereas thick films can easily process waveguides, and conventional aromatic-containing polymer optical materials form thin films. In contrast, the molecular chain had a large birefringence due to light distribution, whereas the birefringence was 1 × 10^-3This makes it possible to reduce the polarization dependence of an optical waveguide manufactured using the material to an allowable value or less. By adjusting the degree of polymerization, the optical material can obtain an appropriate viscosity corresponding to the positive formation of the thin film.
[0036]
Hereinafter, the contents of the present invention will be described in more detail.
[0037]
Polymerization of the epoxy oligomer material of the present invention is carried out by polymerizing by a light reaction between reactive groups contained in the component represented by the general formula. In order to cause the reaction to occur efficiently and sufficiently, it is desirable to add a photopolymerization initiator. Any photopolymerization initiator may be used as long as it is generally used as a photopolymerization initiator.Diphenyltriketone benzoin, benzoin methyl ether, benzophenone, acetophenone, peroxides such as carbonyl compounds such as diacetyl and benzoyl peroxide, An azo compound such as azobisisobutyronitrile is mentioned as a typical example.
[0038]
The polymerization of the silicone oligomer material of the present invention is based on the reaction between the photosensitive agent and the oligomer. As photosensitizers, azide compounds such as azidopyrene, 4,4'-diazidobenzalacetone, 2,6-di- (4'-azidobenzal) cyclohexano, 2,6-di- (4'-azidobenzal) -4 Bisazide compounds such as methylcyclohexanone and diazo compounds are typical.
[0039]
According to the present invention,The above-mentioned photosensitive oligomer materialIn the case where an optical waveguide is manufactured by using the method, the process can be performed as follows. That is,Put the photosensitive oligomer in the reservoirA waveguide pattern is formed by aligning and irradiating light through a mask or directly, and dissolving and removing the non-irradiated portion with a solvent. The optical waveguide thus manufactured has excellent solvent resistance, low polarization dependence due to low birefringence of the material used, low waveguide loss, and excellent heat resistance and moisture resistance.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a method for forming a polymer optical waveguide pattern for diameter conversion based on the present invention will be described in detail below. Of course, the present invention is not limited to these embodiments, and those skilled in the art can easily understand that various modifications and other embodiments are possible within the spirit and scope of the present invention. Like.
[0041]
<Example 1>
A polymer optical waveguide pattern for diameter conversion was formed as follows.
[0042]
First, a solution 10 in which a liquid epoxy oligomer having the structural formula (6) shown below and a photopolymerization initiator of 2% by weight were prepared was prepared.
[0043]
Embedded image
[0044]
(Where n is 1, 2 or 3)
Next, as shown in FIG. 1A, a platform 12 was prepared in which a 100 μm thick epoxy resin 12a having a liquid reservoir 11 having a depth of 63 μm × width 50 mm × length 50 mm was formed on a substrate 12b. The refractive index of this epoxy resin 12a was 1.52 at a wavelength of 0.85 μm. Subsequently, the solution 10 was injected into the liquid reservoir 11 of the platform 12.
[0045]
After the injection of the solution 10, as shown in FIG. 1B, the platform 12 is irradiated with ultraviolet rays (UV light) 14 through a mask 13 having a plurality of optical waveguide patterns 13a formed of patterns corresponding to the ridges ( FIG. 1 (c)). At this time, the width of each optical waveguide pattern 13a formed on the mask 13 is 52 μm at one end along the longitudinal direction and 60 μm at the other end. Therefore, the width of each optical waveguide pattern 13a changes continuously along the longitudinal direction. The irradiation amount of the UV light 14 is also 1700 mJ / cm with respect to the one end according to the change in the width of each optical waveguide pattern 13a.²  To 2000 mJ / cm from the other end²  Continuously.
[0046]
After irradiation with UV light, the sample was developed using an isopropanol solution. As a result, according to the optical waveguide pattern 13a of the mask 13, the liquid epoxy oligomer was hardened only in the light-irradiated portion, and a ridge pattern 15 having a shape as shown in FIG. The refractive index after curing was 1.535 at a wavelength of 0.85 μm. Thereafter, an epoxy resin whose refractive index at the time of photocuring was adjusted to 1.52 at a wavelength of 0.85 μm was further applied and cured on the ridge pattern 15 to produce an optical waveguide.
[0047]
By such an operation, the clad 16 made of an epoxy resin having a refractive index of 1.52 and the core 17 in which the width of the core having a refractive index of 1.535 is continuously changed from 52 μm to 60 μm along the longitudinal direction. A multi-mode channel optical waveguide 18 was obtained (see FIGS. 1E and 1F).
[0048]
The multi-mode channel optical waveguide 18 was cut out by a dicing saw so that each side had a length of 5 cm, and the insertion loss was measured using a GI fiber having a diameter of 50 μm and a diameter of 62.5 μm. It was 1.5 dB or less at 1.3 μm, and 3.0 dB or less at a wavelength of 1.55 μm. The coupling loss with the fiber at that time was 0.1 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0049]
<Example 2>
FIG. 2 is a view for explaining each step of the method for forming an optical waveguide pattern according to the present embodiment.
[0050]
First, as shown in FIG. 2A, a platform 22a having a thickness of 100 μm and made of an epoxy resin 22a having a liquid reservoir 21 was provided on a substrate 22b. The refractive index of this epoxy resin was 1.52 at a wavelength of 0.85 μm. The liquid reservoir 21 has a size of 50 mm in width × 50 mm in length, and its depth continuously changes from one end to the other end (that is, one end is 52 μm and the other end is 52 μm). Is 60 μm). A V-shaped or rectangular groove 22c is formed on a platform 22a located on both sides of the liquid reservoir 21 along the direction in which the depth gradient is formed, and a GI optical fiber ( A diameter 62.5 μm) 23 and a GI optical fiber (diameter 50 μm) 24 are arranged. The optical fiber 23 and the optical fiber 24 face each other with the liquid reservoir 21 interposed therebetween.
[0051]
Next, the solution 10 having the same composition as that prepared in Example 1 was injected into the liquid reservoir 11 (see FIG. 2A).
[0052]
After the injection of the solution 10, as shown in FIG. 2B, the platform 22 is irradiated with ultraviolet rays (UV light) 26 via a mask 25 having a plurality of optical waveguide patterns 25 a formed of patterns corresponding to the ridges ( FIG. 2 (c)). At this time, the width of each optical waveguide pattern 25a formed on the mask 25 is 52 μm at one end along the longitudinal direction and 60 μm at the other end. Therefore, the width of each optical waveguide pattern 25a changes continuously along the longitudinal direction as the depth changes. The irradiation amount of the UV light 26 is uniformly 2000 mJ / cm with respect to the optical waveguide pattern 25a.²  And
[0053]
After irradiation with UV light, the sample was developed using an isopropanol solution. As a result, in accordance with the optical waveguide pattern 25a of the mask 25, the liquid epoxy oligomer was cured only in the light-irradiated portion, and a ridge pattern 27 having a shape as shown in FIG. The refractive index after curing was 1.535 at a wavelength of 0.85 μm. Thereafter, an epoxy resin whose refractive index at the time of photocuring was adjusted to 1.52 at a wavelength of 0.85 μm was further applied to the ridge pattern and cured to produce an optical waveguide (FIG. 2E). reference).
[0054]
By such an operation, a multi-layer having a clad 28 made of an epoxy resin having a refractive index of 1.52 and a core 27 having a core having a refractive index of 1.535 continuously changed from 52 μm to 60 μm along the longitudinal direction. A mode channel optical waveguide 29 was obtained.
[0055]
The multimode channel optical waveguide was cut out with a dicing saw so that each side had a length of 5 cm, and the insertion loss was measured using GI fibers having a diameter of 50 μm and a diameter of 62.5 μm. It was 1.5 dB or less at 1.3 μm, and 3.0 dB or less at a wavelength of 1.55 μm. At that time, the coupling loss with the optical fiber was 0.1 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0056]
<Example 3>
An optical waveguide pattern was formed in the same manner as in Example 2, except that the composition of the resin used to form the optical waveguide was changed.
[0057]
In this example, a multimode channel waveguide was manufactured using a solution prepared by adjusting a liquid silicone epoxy oligomer represented by the following structural formula (7) and 2% by weight of a photopolymerization initiator.
[0058]
Embedded image
[0059]
This optical waveguide was cut out to a length of 5 cm by a dicing saw, and the insertion loss was measured using GI fibers having a diameter of 50 μm and a diameter of 62.5 μm. It was 5 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. The coupling loss with the fiber at that time was 0.1 dB or less. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0060]
<Example 4>
An optical waveguide pattern was formed in the same manner as in Example 2, except that the composition of the resin used to form the optical waveguide was changed.
[0061]
In this example, a multimode channel waveguide was manufactured using a solution prepared by adjusting a liquid silicone epoxy oligomer represented by the following structural formula (8) and 2 parts by weight of a photopolymerization initiator.
[0062]
Embedded image
[0063]
This optical waveguide was cut out to a length of 5 cm by a dicing saw, and the insertion loss was measured using GI fibers having a diameter of 50 μm and a diameter of 62.5 μm. It was 5 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. The coupling loss with the fiber at that time was 0.1 dB or less. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0064]
<Example 5>
An optical waveguide pattern was formed in the same manner as in Example 2, except that the composition of the resin used to form the optical waveguide was changed.
[0065]
A channel waveguide for a multi-mode was prepared using a solution prepared by adjusting a liquid silicone oligomer represented by the following structural formula (9) and 2 parts by weight of a photopolymerization initiator.
[0066]
Embedded image
[0067]
(Where X: Y = 7: 5)
The optical waveguide was cut into a length of 5 cm by a dicing saw, and the insertion loss was measured using GI fibers having a diameter of 50 μm and a diameter of 62.5 μm. It was 5 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. The coupling loss with the fiber at that time was 0.1 dB or less. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0068]
<Example 6>
An optical waveguide pattern was formed in the same manner as in Example 2, except that the composition of the resin used to form the optical waveguide was changed.
[0069]
That is, a solution prepared by adjusting a liquid silicone vinyl ether oligomer represented by the following structural formula (10) and 2% by weight of a photopolymerization initiator was used.
[0070]
Embedded image
[0071]
The obtained optical waveguide was cut out to a length of 5 cm by a dicing saw, and the insertion loss was measured using GI fibers having a diameter of 50 μm and a diameter of 62.5 μm. It was 1.5 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. The coupling loss with the fiber at that time was 0.1 dB or less. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0072]
<Example 7>
An optical waveguide pattern was formed in the same manner as in Example 2, except that the composition of the resin used to form the optical waveguide was changed.
[0073]
In this example, a solution was prepared in which a liquid acrylic oligomer having the structural formula (11) shown below and a photopolymerization initiator in an amount of 2 wt.
[0074]
Embedded image
[0075]
The produced multimode optical waveguide was cut out to a length of 5 cm with a dicing saw, and the insertion loss was measured using GI fibers having a diameter of 50 μm and a diameter of 62.5 μm. It was 1.5 dB or less at 55 μm. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. The coupling loss with the fiber at that time was 0.1 dB or less. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH.
[0076]
Example 8
Using a solution prepared from the liquid silicone epoxy oligomer used in Example 2 and 2% by weight of a photopolymerization initiator, a multi-channel optical waveguide was produced according to the process shown in FIG. 2 to interconnect a transmitting / receiving device.
[0077]
First, as shown in FIG. 2A, a platform 22 made of an epoxy resin 22a having a thickness of 100 μm and having a liquid reservoir 21 was provided on a substrate 22b. The refractive index of this epoxy resin was 1.52 at a wavelength of 0.85 μm. The liquid reservoir 21 has a size of 50 mm in width × 50 mm in length, and its depth continuously changes from one end to the other end (that is, one end is set to 48 μm and the other end is set to 48 μm). Is 4 μm). A V-shaped or rectangular groove 22c is formed on a platform 22a located on both sides of the liquid reservoir 21 along the direction in which the depth gradient is formed, and a laser light source (oscillation) is formed in the groove 22c. (Wavelength 0.85 μm) 23 and the light receiver 24 are arranged so as to face each other with the liquid reservoir 21 interposed therebetween. Here, the light emitting area of the laser light source 23 is 2 × 5 μm, and the light receiving surface of the light receiver 24 has a diameter of 50 μm.
[0078]
Next, the solution 10 having the same composition as that prepared in Example 1 was injected into the liquid reservoir 11 (see FIG. 2A).
[0079]
After the injection of the solution 10, as shown in FIG. 2B, the platform 22 is irradiated with ultraviolet rays (UV light) 26 via a mask 25 having a plurality of optical waveguide patterns 25 a formed of patterns corresponding to the ridges ( FIG. 2 (c)). At this time, the width of each optical waveguide pattern 25a formed on the mask 25 is 48 μm at one end along the longitudinal direction and 4 μm at the other end. Therefore, the width of each optical waveguide pattern 25a changes continuously along the longitudinal direction as the depth changes. The irradiation amount of the UV light 26 is uniformly 2000 mJ / cm with respect to the optical waveguide pattern 25a.²  And
[0080]
After irradiation with UV light, the sample was developed using an isopropanol solution. As a result, in accordance with the optical waveguide pattern 25a of the mask 25, the liquid epoxy oligomer was cured only in the light-irradiated portion, and a ridge pattern 27 having a shape as shown in FIG. The refractive index after curing was 1.52 at a wavelength of 0.85 μm. Thereafter, an epoxy resin adjusted to have a refractive index of 1.52 at a wavelength of 0.85 μm at the time of photo-curing was further applied to the ridge pattern and cured to produce a multi-mode channel optical waveguide 29 (FIG. 2 (e)).
[0081]
By such an operation, a multi-layer having a clad 28 made of an epoxy resin having a refractive index of 1.52 and a core 27 having a core diameter having a refractive index of 1.535 continuously changed from 48 μm to 2 μm along the longitudinal direction. An optical waveguide device 200 having the mode channel optical waveguide 29 was obtained (see FIG. 2F).
[0082]
When light was introduced by interconnecting the optical transmitting and receiving device with the multimode channel optical waveguide element 200, the coupling loss on the transmitting side was about 0.3 dB and the coupling loss on the receiving side was about 0.1 dB.
[0083]
<Example 9>
A multi-channel optical waveguide according to the process shown in FIG. 2 in the same manner as in Example 8 except that a solution prepared from the liquid silicone epoxy oligomer used in Example 3 and 2% by weight of a photopolymerization initiator was used. Was fabricated and the transmitting and receiving devices were interconnected.
[0084]
Using the multi-channel optical waveguide obtained in this manner, a waveguide device 200 in which an optical transmitting and receiving device is interconnected was manufactured (FIG. 2E). When light was introduced into the optical waveguide from 22, the coupling loss was about 0.3 dB and the coupling loss on the light receiving side was about 0.1 dB.
[0085]
<Example 10>
A multi-channel optical waveguide according to the process shown in FIG. 2 in the same manner as in Example 8 except that a solution prepared from the liquid silicone epoxy oligomer used in Example 4 and 2% by weight of the photopolymerization initiator was used. Was fabricated and the transmitting and receiving devices were interconnected.
[0086]
Using the multi-channel optical waveguide thus obtained, an optical waveguide device 200 in which an optical transmitting / receiving device is interconnected was manufactured (FIG. 2 (f)). When light was introduced into the optical waveguide from 22, the coupling loss was about 0.3 dB and the coupling loss on the light receiving side was about 0.1 dB.
[0087]
<Example 11>
A multi-channel optical waveguide according to the process shown in FIG. 2 in the same manner as in Example 8 except that a solution prepared from the liquid silicone epoxy oligomer used in Example 5 and 2% by weight of a photopolymerization initiator was used. Was fabricated and the transmitting and receiving devices were interconnected.
[0088]
Using the multi-channel optical waveguide thus obtained, an optical waveguide device 200 in which an optical transmitting / receiving device is interconnected was manufactured (FIG. 2 (f)). When light was introduced into the optical waveguide from 22, the coupling loss was about 0.3 dB and the coupling loss on the light receiving side was about 0.1 dB.
[0089]
<Example 12>
A multi-channel optical waveguide according to the process shown in FIG. 2 in the same manner as in Example 8 except that a solution prepared from the liquid silicone epoxy oligomer used in Example 6 and 2% by weight of the photopolymerization initiator was used. Was fabricated and the transmitting and receiving devices were interconnected.
[0090]
Using the multi-channel optical waveguide thus obtained, an optical waveguide device 200 in which an optical transmitting / receiving device is interconnected was manufactured (FIG. 2 (f)). When light was introduced into the optical waveguide from 22, the coupling loss was about 0.3 dB and the coupling loss on the light receiving side was about 0.1 dB.
[0091]
<Example 13>
A polymer optical waveguide pattern for diameter conversion was formed as follows.
[0092]
First, a solution 30 was prepared in which a liquid epoxy oligomer having the same structural formula (6) as in Example 1 and 2% by weight of a photopolymerization initiator were prepared.
[0093]
Embedded image
[0094]
Next, as shown in FIG. 3A, a platform 32 is prepared in which an epoxy resin 32a having a thickness of 500 μm and a liquid reservoir 31 having a depth of 200 μm-300 μm × width 50 mm × length 50 mm is formed on a substrate 32b. did. A V-shaped or rectangular groove 22c is formed on both sides of the liquid reservoir 31 along the direction in which the depth gradient is formed, and the polymer clad fiber 39 and the LED 301 are arranged in the groove 32c. The refractive index of this epoxy resin 12a was 1.52 at a wavelength of 0.85 μm. Subsequently, the solution 30 was injected into the liquid reservoir 31 of the platform 32.
[0095]
After the injection of the solution 10, as shown in FIG. 3B, the platform 32 is irradiated with ultraviolet rays (UV light) 34 via a mask 33 having a plurality of optical waveguide patterns 33a formed of patterns corresponding to the ridges ( FIG. 3 (c)). At this time, the width of each optical waveguide pattern 33a formed on the mask 33 is 200 μm at one end along the longitudinal direction and 300 μm at the other end. Therefore, the width of each optical waveguide pattern 33a changes continuously along the longitudinal direction. The irradiation amount of the UV light 34 is also 1700 mJ / cm with respect to the one end according to the change in the width of each optical waveguide pattern 33a.²  To 2000 mJ / cm from the other end²  Continuously.
[0096]
After irradiation with UV light, the sample was developed using an isopropanol solution. As a result, according to the optical waveguide pattern 33a of the mask 33, the liquid epoxy oligomer was hardened only in the light irradiation part, and a ridge pattern 35 having a shape as shown in FIG. The refractive index after curing was 1.54 at a wavelength of 0.85 μm. Thereafter, an epoxy resin adjusted to have a refractive index of 1.51 at a wavelength of 0.85 μm at the time of photocuring was further applied to the ridge pattern and cured to produce an optical waveguide.
[0097]
By such an operation, the clad 36 made of the epoxy resin having the refractive index of 1.51 and the core 37 having the core having the refractive index of 1.54 continuously changed from 200 μm to 300 μm along the longitudinal direction are provided. A multi-mode channel optical waveguide 38 was obtained (see FIG. 3E).
[0098]
The multimode channel optical waveguide 38 was cut out by a dicing saw so as to have a side of 5 cm in length, and the insertion loss was measured using a polymer-graded fiber 39 having an inner diameter of 200 μm and an outer diameter of 230 μm. It was 1 dB or less at 85 μm, 1 dB or less at 0.633 μm, and 3.0 dB or less at a wavelength of 1.3 μm. The coupling loss with the fiber at that time was 0.1 dB or less. The polarization dependence of the insertion loss was 0.1 dB or less at both 1.3 μm and 1.55 μm. Further, the loss of the optical waveguide did not fluctuate for more than one month even under the condition of 75 ° C./90% RH. Further, as shown in FIG. 3 (f), an LED (light emitting area 250 μm, oscillation wavelength 0.66 μm) 301 is mounted on the side of the core diameter 300 μm indicated by reference numeral 300 of the multimode channel optical waveguide 38 to perform optical coupling. went. As a result, the coupling loss between the LED and the optical waveguide was a good value of about 1 dB.
[0099]
According to the method for forming a polymer optical waveguide pattern for diameter conversion based on the above Examples 1 to 13, the photosensitive material used in Examples 1 to 13 has a simple pattern forming ability, and has heat resistance and moisture resistance. Because of its excellent properties and low birefringence, it is possible to easily connect to optical components.
[0100]
【The invention's effect】
As described above, according to the method for forming a diameter-converting polymer optical waveguide pattern based on the present invention, mass-produced diameter-converting polymer optical waveguide components simplifying connection between components in optical communication and optical information processing systems. It is easy to reduce the cost. Furthermore, the present invention makes it possible to realize aperture conversion of a light beam, which is important in connection, so that various optical waveguides and optical waveguides used in the fields of general optics and micro optics, optical communication and optical information processing can be realized. The aperture conversion function can be easily incorporated into an integrated circuit or an optical wiring board.
[Brief description of the drawings]
FIG. 1 is a view for explaining a method of forming a polymer optical waveguide pattern for diameter conversion according to the present invention, and (a) to (f) are schematic views showing respective steps.
FIGS. 2A to 2F are diagrams for explaining a method of forming a polymer optical waveguide pattern for diameter conversion based on the present invention, wherein FIGS.
FIGS. 3A to 3F are diagrams for explaining a method for forming a polymer optical waveguide pattern for diameter conversion based on the present invention, and FIGS.
[Explanation of symbols]
10 solutions
11 liquid storage
12 platforms
13 Mask
14 UV light
15 Ridge pattern
16 cladding
17 core
18 Multimode channel optical waveguide
20 solutions
21 Liquid storage
22 grooves
23 Optical fiber (or semiconductor laser light source)
24 Optical fiber (or receiver)
25 Mask
26 UV light
27 Ridge pattern
28 cladding
29 Multimode Channel Optical Waveguide
30 solutions
31 Liquid reservoir
32 platforms
33 Mask
34 UV light
35 Ridge pattern
36 cladding
37 core
38 Multimode Channel Optical Waveguide
39 polymer clad fiber
200 Optical waveguide device
300 core diameter 300μm side
301 LED

Claims (8)

Preparing a liquid storage pool, filling the liquid pool with a liquid photosensitive substance containing a photosensitive oligomer and a photopolymerization initiator, and irradiating a predetermined portion of the photosensitive substance with a mask or directly. Irradiating, a step of forming a pattern latent image having a width that changes continuously along the longitudinal direction, and a step of removing the other portion of the photosensitive material that has not been subjected to the light irradiation with a solvent, at least Including
Continuously changing the light intensity of the light irradiation,
The predetermined portion where the pattern latent image is formed constitutes the core portion of the optical waveguide, the bottom of the liquid storage pool constitutes the lower cladding portion of the optical waveguide, and the photosensitive oligomer is represented by the following general formula (1)
(Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a trifluoromethyl group, and X ₁ , X ₂ and X ₃ represent an alkyl group, an alkyl ether group and an aromatic ring And represents a linking group containing at least one OH group, and Y is
Or
Represents a polymerization active group. An epoxy oligomer represented by the following general formula (2)
(Wherein, 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. Z represents an epoxy group represented by the following formula (I) or (II)) ,
x and y indicate the proportion of each unit, and y may be smaller than x and may be 0), a liquid silicone epoxy oligomer represented by the following general formula (3)
(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 each represent an 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.) A liquid silicone oligomer represented by the following general 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 each represent an abundance ratio of each unit. R represents a methyl group, an ethyl group or an isopropyl group), and a liquid silicone vinyl ether oligomer represented by the following general formula (5):
(Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a trifluoromethyl group, and X ₁ , X ₂ and X ₃ represent an alkyl group, an alkyl ether group and an aromatic ring Represents a linking group containing
Or
Represents a polymerization active group. A) a method selected from the group consisting of acrylic oligomers represented by the formula (1). 2. The polymer optical waveguide for diameter conversion according to claim 1, wherein the liquid storage pool has grooves for aligning and arranging an optical fiber and / or a smiling optical element on both sides of the optical waveguide facing in the longitudinal direction. Pattern forming method. 3. The method of claim 2, wherein the micro optical element is selected from the group consisting of a laser diode (LD), a light emitting diode (LED), and a light receiving diode (PD). The photosensitive oligomer has a general formula (6)
2. The method for forming a polymer optical waveguide pattern for diameter conversion according to claim 1, which is an epoxy oligomer represented by the formula: The photosensitive oligomer has a general formula (7)
2. The method for forming a polymer optical waveguide pattern for diameter conversion according to claim 1, which is a liquid silicone epoxy oligomer represented by the formula: The photosensitive oligomer has a general formula (9)
The method for forming a polymer optical waveguide pattern for diameter conversion according to claim 1, which is a liquid silicone oligomer represented by the following formula: The photosensitive oligomer has a general formula (10)
2. The method for forming a polymer optical waveguide pattern for diameter conversion according to claim 1, which is a liquid silicone vinyl ether oligomer represented by the formula: The photosensitive oligomer has a general formula (11)
2. The method for forming a polymer optical waveguide pattern for diameter conversion according to claim 1, which is a liquid acrylic oligomer represented by the formula: