JP5560846B2 - Photosensitive resin composition, optical waveguide forming film, optical waveguide, optical wiring, opto-electric hybrid board, and electronic device - Google Patents

Description

  The present invention relates to a photosensitive resin composition, a film for forming an optical waveguide, an optical waveguide, an optical wiring, an opto-electric hybrid board, and an electronic device.

  2. Description of the Related Art In recent years, with the increase in the amount of data communication, optical communication has attracted attention as a means for solving signal interference and attenuation that are problematic in conventional electrical transmission. Glass optical fiber is most frequently used as an optical transport medium, but it is not preferable for complicated high-density circuits because the use of high-density circuits causes problems in use and increases costs. . On the other hand, an optical waveguide using a polymer material as an optical transport medium is capable of creating a reliable and practical component at a reasonable cost, and can perform functions necessary for integrated optics. Promising.

  The optical waveguide includes a core portion that transmits light and a clad portion that is made of a material having a lower refractive index than the core portion (see Patent Document 1). Optical waveguides need to reduce optical loss, and the materials are required to have high transparency, no light-scattering impurities and irregularities at the core / cladding interface, and high core / cladding adhesion. .

Japanese Patent Publication No. 2005-221556

In view of the above circumstances, an object of the present invention is to provide a photosensitive resin composition having high productivity and low light loss.
Another object of the present invention is to provide a film for forming an optical waveguide, an optical waveguide, an optical wiring, an opto-electric hybrid board, and an electronic device with high productivity and low optical loss by using the photosensitive resin composition.

Such an object is achieved by the present invention described in the following (1) to ( 12 ).
(1) A photosensitive resin composition for forming an optical waveguide, and alicyclic epoxy monomer having two or more (A) functional groups, and (B) silsesquioxane, and (C) an acid generator The photosensitive resin composition characterized by including.
(2) The (A) alicyclic epoxy monomer having two or more functional groups is (3′-4′-Epoxycyclohexane) methyl 3′-4′-Epoxycyclohexyl-carboxylate, (3′-4′-Epoxycyclohexane) The photosensitive resin composition according to (1), wherein the photosensitive resin composition is selected from the group consisting of methyl 3′-4′-Epoxycyclohexyl-carboxylate modified-caprolactone.
(3) The photosensitive resin composition according to (1) or (2) , wherein the silsesquioxane is represented by the following formula (24).

( 4 ) The weight ratio (A) / (B) of the alicyclic epoxy monomer having two or more functional groups (A) and the oxetane monomer having two or more functional groups (B) is 99 / 1-20. The photosensitive resin composition in any one of said (1) thru | or ( 3 ) which is / 80.
( 5 ) A film for forming an optical waveguide, wherein the photosensitive resin composition according to any one of (1) to ( 4 ) is used.
( 6 ) An optical waveguide characterized by being formed using the optical waveguide forming film described in ( 5 ).
( 7 ) The optical waveguide according to ( 6 ), which has a core portion formed using a cyclic olefin resin.
( 8 ) The optical waveguide according to ( 7 ), wherein the cyclic olefin resin is a norbornene resin.
( 9 ) The optical waveguide according to ( 8 ), wherein the norbornene resin is represented by the following formula (10).

( 10 ) An optical wiring comprising the optical waveguide according to any one of ( 6 ) to ( 9 ).
( 11 ) An opto-electric hybrid board, comprising electrical wiring and the optical wiring according to ( 10 ).
( 12 ) An electronic apparatus comprising the optical waveguide according to any one of ( 6 ) to ( 11 ).

According to the present invention, a photosensitive resin composition having high productivity and low light loss can be provided.
Further, by using the photosensitive resin composition, it is possible to obtain a film for forming an optical waveguide, an optical wiring, an opto-electric hybrid board, and an electronic device with high productivity and low optical loss.

It is sectional drawing which shows an example of the optical waveguide of this invention. It is sectional drawing which shows an example of the process of manufacturing the optical waveguide of this invention.

  Hereinafter, the photosensitive resin composition, the film for forming an optical waveguide, the optical waveguide, the optical wiring, the opto-electric hybrid board and the electronic device of the present invention will be described.

The photosensitive resin composition of the present invention is a photosensitive resin composition for forming an optical waveguide, and (A) an alicyclic epoxy monomer having two or more functional groups and / or (B) two functional groups. It contains the oxetane monomer having the above and (C) an acid generator.
The film for forming an optical waveguide of the present invention is characterized in that the photosensitive resin composition is used.
The optical waveguide of the present invention is formed using the film for forming an optical waveguide.
An optical wiring according to the present invention includes the optical waveguide.
The opto-electric hybrid board according to the present invention includes an electrical wiring and the optical wiring.
An electronic apparatus according to the present invention includes the optical waveguide.

First, the photosensitive resin composition will be described.
A photosensitive resin composition for forming an optical waveguide, wherein (A) an alicyclic epoxy monomer having two or more functional groups and / or (B) an oxetane monomer having two or more functional groups, and (C) an acid And a generator.

First, (A) an alicyclic epoxy monomer having two or more functional groups will be described.
The alicyclic epoxy monomer is rich in reactivity because it has a larger structural strain than other epoxy monomers. The (A) alicyclic epoxy monomer having two or more functional groups is not particularly limited, but 1,2: alicyclic epoxy 8,9 diepoxy limonene (Daicel Chemical Industries, Ltd. CEL3000), 3'-4 '-Epoxycyclohexane) methyl 3'-4'-Epoxycyclohexyl-carboxylate (Daicel Chemical Industry Co., Ltd. CEL2021), (3'-4'-Epoxycyclohexane) methyl 3'-4'-Epoxycycylcyclohexane Company CEL-2081), 1,4-Cyclohexanedimethanol bis (3,4-epoxycyclohexanecarboxylate) (Kitamura Industrial Chemical Co., Ltd. ERLX-4360) and the like, and in particular, (3′-4′-Epoxycyclohexane) methyl 3′-4′-Epoxycyclohexyl-carboxylate (Daicel Chemical Industries, Ltd. CEL2021), (3′-4 ′). -Epoxycyclohexane) methyl 3'-4'-Epoxycyclohexyl-carboxy modified -caprolactone (CEL-2081), 1,4-Cyclohexanediol bis (3), e-cyclohexane (43) Thereby, it is possible to obtain a photosensitive resin composition having high reactivity, excellent flexibility, and high transparency.

  Next, (B) the oxetane monomer having two or more functional groups will be described. The oxetane monomer is 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl (Ube Industries, Ltd. ETERNACOLL OXBP), 3-ethyl-3 {[((3-ethyloxetane-3-yl) Methoxy] methyl} oxetane (DOA), poly [[3-[(3-ethyl-3-oxetanyl) methoxy] propyl] silasesquioxane] derivative (Toa Gosei OX-SQ-H) However, those having a silsesquioxane structure are particularly useful. For example, poly [[3-[(3-ethyl-3-oxetanyl) methoxy] propyl] silacese having high compatibility with the alicyclic epoxy monomer. Sukioxane] derivatives and the like are preferable. By using such an inorganic / organic composite material, a high crosslink density and appropriate flexibility can be imparted to the molded body of the photosensitive resin composition (such as the optical waveguide forming film of the present invention).

  In addition, since the molded product of the photosensitive resin composition of the present invention has a high crosslinking density, even if a material containing a small compound such as a monomer is applied to the optical waveguide forming film of the present invention described later, It is possible to prevent penetration into the optical waveguide forming film.

  The weight ratio (A) / (B) of the alicyclic epoxy monomer having two or more functional groups (A) and the oxetane monomer having two or more functional groups (B) is 99/1 to 20/80. 95/5 to 30/70 is particularly preferable. More preferably, it is 80 / 20-40 / 60. By setting such a weight ratio, the molded body of the resin composition has (A) high flexibility derived from an alicyclic epoxy monomer having two or more functional groups and (B) two or more functional groups. Both properties of high crosslink density derived from the oxetane monomer possessed can be obtained. Furthermore, by mixing and polymerizing an alicyclic epoxy monomer having two or more functional groups (A) having a fast initiation reaction and an oxetane monomer having two or more functional groups (B) having a fast growth reaction, the reaction rate Can be increased, and the productivity is excellent.

The acid generator (C) is not particularly limited as long as it generates an acid, and examples thereof include an acid generator that generates an acid by light or heat. Among them, in particular, a photoacid generator that generates Bronsted acid or Lewis acid by absorbing light energy by light irradiation is preferable because it can cure only an arbitrary place, and thus has high workability.
For example, sulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, tris (4-t-butylphenyl) sulfonium-trifluoromethanesulfonate, diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate, ammonium salts, phosphonium salts, diphenyliodonium Trifluoromethanesulfonate, iodonium salts such as (tricumyl) iodonium-tetrakis (pentafluorophenyl) borate, quinonediazides, diazomethanes such as bis (phenylsulfonyl) diazomethane, 1-phenyl-1- (4-methylphenyl) sulfonyloxy- Sulfones such as 1-benzoylmethane and N-hydroxynaphthalimide-trifluoromethanesulfonate Esters, disulfones such as diphenyldisulfone, tris (2,4,6-trichloromethyl) -s-triazine, 2- (3,4-methylenedioxyphenyl) -4,6-bis- (trichloromethyl)- Examples thereof include compounds such as triazines such as s-triazine. These photoacid generators can be used alone or in combination.

  By including the (A) alicyclic epoxy monomer having two or more functional groups, the (B) oxetane monomer having two or more functional groups, and the (C) acid generator, the transparency is high. A photosensitive resin composition preferable for forming an optical waveguide free from impurities that cause light scattering can be obtained. The photosensitive resin composition of the present invention can be used as both a material for a core layer (hereinafter referred to as a core material) and a material for a cladding portion (hereinafter referred to as a cladding material) in forming an optical waveguide. .

A solvent may be added to the photosensitive resin composition as necessary. Examples of the solvent include toluene, xylene, mesitylene, tetrahydrofuran, cyclohexane, cyclohexanone, cyclopentane, cyclopentanone, methyl ethyl ketone, 2-heptanone, limonene, decalin and the like. Of these, toluene and methyl ethyl ketone are particularly preferable. These solvents are excellent in solubility of (A) an alicyclic epoxy monomer having two or more functional groups and (B) an oxetane monomer having two or more functional groups, and uniform the photosensitive resin composition. can do. In addition, the content of the solvent in the resin composition is preferably 5 to 70% by weight, and particularly preferably 20 to 50% by weight. Thereby, applicability | paintability becomes high and the film for optical waveguide formation mentioned later can be shape | molded easily to desired thickness.
The photosensitive resin composition of the present invention comprises (A) an alicyclic epoxy monomer having two or more functional groups, (B) an oxetane monomer having two or more functional groups, (C) an acid generator and a solvent. In addition, additives such as a sensitizer and a silane coupling agent may be added as necessary.

The film for forming an optical waveguide of the present invention is formed using the photosensitive resin composition.
Since the photosensitive resin composition of the present invention includes the alicyclic epoxy monomer having two or more functional groups (A) that imparts flexibility, the photosensitive resin composition has flexibility easily when applied on a substrate. An optical waveguide forming film can be obtained. Since the photosensitive resin composition of the present invention has a high crosslinking density, when another material is brought into close contact with the optical waveguide forming film, a part of one material (for example, a monomer or the like having a low molecular weight) is formed at the interface. Compound) does not penetrate into the other. Therefore, for example, even if the film for forming an optical waveguide of the present invention is used as a first clad layer and a core layer using a resin composition having a different composition is directly formed on the first clad layer, the function of the core layer is maintained. An optical waveguide having high light propagation performance can be formed without damage.

Next, the optical waveguide of the present invention will be described.
FIG. 1 is a cross-sectional view showing an example of an optical waveguide of the present invention.
As shown in FIG. 1, the optical waveguide 10 includes a first cladding layer 1, a core layer 2 having a higher refractive index than the first cladding layer, and a second cladding layer 3 having a lower refractive index than the core layer 2. Are stacked.
The core layer 2 includes a core portion 21 and a side clad portion 22 having a refractive index lower than that of the core portion 21. Note that the refractive index of the core portion 21 is higher than that of the first cladding layer 1 and the second cladding layer 3.
By having such a configuration, the optical signal incident on one end side of the core portion 21 is totally reflected at the interface between the core portion 21 and the first cladding layer 1, the second cladding layer 3, and the side cladding portion 22. , Transmitted to the other end side, and optical communication becomes possible.

  The film for forming an optical waveguide of the present invention can also be used for the first cladding layer 1 and / or the second cladding layer 3 and the core layer 2 of the optical waveguide 10 described above. Among these, it can be suitably used particularly for the first cladding layer 1 and the second cladding layer 3.

  When the optical waveguide forming film of the present invention is used as the first cladding layer 1 and the second cladding layer 3, the material used for the core layer 2 is not particularly limited. For example, acrylic resin, methacrylic resin, polycarbonate, polystyrene , Epoxy resin, polyamide, polyimide, polybenzoxazole, polysilane, polysilazane, and various resin materials such as cyclic olefin resin such as benzocyclobutene resin and norbornene resin, quartz glass, borosilicate glass, etc. Glass materials and the like. Among these, it is particularly preferable to use a cyclic olefin resin as the core layer 2. The photosensitive resin film of this invention is excellent in adhesiveness (wettability) with the material containing especially cyclic olefin fat.

The said cyclic olefin resin is added in order to ensure the film moldability of a core material, and becomes a base polymer.
Here, the cyclic olefin resin may be unsubstituted, or hydrogen may be substituted with another group. Examples of the cyclic olefin resin include norbornene resins and benzocyclobutene resins.
Especially, it is preferable to use norbornene-type resin from viewpoints, such as heat resistance and transparency.

As norbornene resin, for example,
(1) addition (co) polymer of norbornene type monomer obtained by addition (co) polymerization of norbornene type monomer,
(2) an addition copolymer of a norbornene monomer and ethylene or α-olefins,
(3) an addition polymer such as an addition copolymer of a norbornene-type monomer and a non-conjugated diene and, if necessary, another monomer;
(4) a ring-opening (co) polymer of a norbornene-type monomer, and a resin obtained by hydrogenating the (co) polymer if necessary,
(5) a ring-opening copolymer of a norbornene-type monomer and ethylene or α-olefins, and a resin obtained by hydrogenating the (co) polymer if necessary,
(6) Ring-opening copolymers such as norbornene-type monomers and non-conjugated dienes, or other monomers, and polymers obtained by hydrogenating the (co) polymers as necessary. Examples of these polymers include random copolymers, block copolymers, and alternating copolymers.

  These norbornene resins include, for example, ring-opening metathesis polymerization (ROMP), combination of ROMP and hydrogenation reaction, polymerization by radical or cation, polymerization using cationic palladium polymerization initiator, other polymerization initiators ( For example, it can be obtained by any known polymerization method such as polymerization using a polymerization initiator of nickel or another transition metal).

  Among these, as the norbornene-based resin, an addition (co) polymer is preferable. Addition (co) polymers are also preferred because they are rich in transparency, heat resistance and flexibility. For example, after forming an optical waveguide, an electrical component or the like may be mounted via solder. In such a case, an addition (co) polymer is preferable because it needs to have high heat resistance, that is, reflow resistance. Moreover, when an optical waveguide is formed and incorporated in a product, it may be used in an environment of about 80 ° C., for example. Even in such a case, an addition (co) polymer is preferred because it is necessary to have heat resistance.

  Among them, the norbornene-based resin preferably includes a norbornene repeating unit having a substituent containing a polymerizable group or a norbornene repeating unit having a substituent containing an aryl group.

  As the repeating unit of norbornene having a substituent containing a polymerizable group, the repeating unit of norbornene having a substituent containing an epoxy group, the repeating unit of norbornene having a substituent containing a (meth) acryl group, and an alkoxysilyl group At least one of the repeating units of norbornene having a substituent containing is preferable. These polymerizable groups are preferable because of their high reactivity among various polymerizable groups.

  Moreover, if the thing containing 2 or more types of norbornene repeating units containing such a polymeric group is used, both flexibility and heat resistance can be achieved.

  On the other hand, by including a norbornene repeating unit having a substituent containing an aryl group, the aryl group has extremely high hydrophobicity, and therefore, dimensional change due to water absorption can be prevented more reliably.

  Furthermore, the norbornene-based polymer preferably contains an alkylnorbornene repeating unit. The alkyl group may be linear or branched.

  By including the repeating unit of alkyl norbornene, the norbornene-based polymer has high flexibility, and thus can provide high flexibility (flexibility).

  A norbornene-based polymer containing an alkylnorbornene repeating unit is also preferable because of its excellent transmittance with respect to light in a specific wavelength region (particularly, a wavelength region near 850 nm).

  Therefore, as the norbornene-based resin, those represented by the following formulas (1), (3) to (5), and (9) to (12) are preferable.

The norbornene-based resin of the formula (1) can be produced as follows.
A norbornene resin of the formula (1) is obtained by dissolving norbornene having R1 in the side chain and norbornene having an epoxy group in the side chain in toluene, and solution polymerizing using a Ni compound (formula (2)) as a catalyst. Can be obtained.

In addition, the manufacturing method of norbornene which has an epoxy group in a side chain is as follows (i) (ii), for example.
(I) Synthesis of norbornenemethanol (NB-CH2-OH) CPD (cyclopentadiene) produced by cracking of DCPD (dicyclopentadiene) and α-olefin (CH2 = CH-CH2-OH) are reacted under high temperature and high pressure.

(Ii) Synthesis of epoxy norbornene It is formed by the reaction of norbornene methanol and epichlorohydrin.

In the formula (1), when b is 2 or 3, an epichlorohydrin in which the methylene group is an ethylene group, a propylene group or the like is used.
Among the norbornene-based resins represented by the formula (1), R1 is particularly an alkyl group having 4 to 10 carbon atoms from the viewpoint of achieving both flexibility and heat resistance, and a and b Are preferably compounds such as butylbornene and methyl glycidyl ether norbornene, hexyl norbornene and methyl glycidyl ether norbornene, decyl norbornene and methyl glycidyl ether norbornene.

  The norbornene-based resin of formula (3) is obtained by dissolving norbornene having R2 and norbornene having acryl and methacryl groups in the side chain in toluene, and solution polymerization using the above-described Ni compound (formula (2)) as a catalyst. Can be obtained.

  Among the norbornene-based polymers represented by formula (3), a compound in which R2 is an alkyl group having 4 to 10 carbon atoms and c is 1 from the viewpoint of achieving both flexibility and heat resistance. For example, a copolymer of butylbornene and 2- (5-norbornenyl) methyl acrylate, a copolymer of hexylnorbornene and 2- (5-norbornenyl) methyl acrylate, decylnorbornene and 2- (5-norbornenyl) methyl acrylate, Of these, the copolymer is preferred.

  The resin of the formula (4) is obtained by dissolving norbornene having R4 and norbornene having an alkoxysilyl group in the side chain in toluene, and performing solution polymerization using the above-described Ni compound (formula (2)) as a catalyst. be able to.

  Among the norbornene polymers represented by the formula (4), particularly, a compound in which R4 is an alkyl group having 4 to 10 carbon atoms, d is 1 or 2, and X3 is a methyl group or an ethyl group, for example, Copolymer of butylbornene and norbornenylethyltrimethoxysilane, copolymer of hexylnorbornene and norbornenylethyltrimethoxysilane, copolymer of decylnorbornene and norbornenylethyltrimethoxysilane, copolymer of butylbornene and triethoxysilylnorbornene , Copolymers of hexyl norbornene and triethoxysilyl norbornene, copolymers of decyl norbornene and triethoxysilyl norbornene, copolymers of butylbornene and trimethoxysilyl norbornene, hexyl norbornene Copolymers of trimethoxysilyl norbornene, copolymers, etc. of decyl norbornene and trimethoxysilyl norbornene are preferred.

  A norbornene resin of formula (5) is obtained by dissolving norbornene having R5 and norbornene having A1 and A2 in the side chain in toluene and solution polymerization using a Ni compound (formula (2)) as a catalyst.

  In addition, as a norbornene-type polymer represented by Formula (5), for example, any one of butyl norbornene, hexyl norbornene, or decyl norbornene, 2- (5-norbornenyl) methyl acrylate, norbornenyl ethyltrimethoxysilane, Terpolymer with either triethoxysilyl norbornene or trimethoxysilyl norbornene, terpolymer of butylbornene, hexylnorbornene or decylnorbornene, 2- (5-norbornenyl) methyl acrylate and methylglycidyl ether norbornene, butylbornene, Either hexyl norbornene or decyl norbornene and methyl glycidyl ether norbornene, norbornenyl ethyltrimethoxysilane, triethoxysilyl Terpolymers, etc. with either Ruborunen or trimethoxysilyl norbornene.

  Norbornene having R7 in the side chain and norbornene containing-(CH2) -X1-X2 (R8) 3-j (Ar) j in the side chain are dissolved in toluene, and solution polymerization is performed using a Ni compound as a catalyst. To obtain a norbornene resin of the formula (9).

Of the norbornene polymers represented by the formula (9), those in which X1 is an oxygen atom, X2 is a silicon atom, and Ar is a phenyl group are preferable.
Further, particularly from the viewpoint of flexibility, heat resistance, and refractive index control, R7 is an alkyl group having 4 to 10 carbon atoms, X1 is an oxygen atom, X2 is a silicon atom, Ar is a phenyl group, and R8 is a methyl group. A compound in which i is 1 and j is 2, for example, a copolymer of butylbornene and diphenylmethylnorbornenemethoxysilane, a copolymer of hexylnorbornene and diphenylmethylnorbornenemethoxysilane, a copolymer of decylnorbornene and diphenylmethylnorbornenemethoxysilane, etc. preferable.

  Specifically, it is preferable to use the following norbornene resin.

From the viewpoint of flexibility, heat resistance, and refractive index control, in Formula (9), R7 is an alkyl group having 4 to 10 carbon atoms, X1 is a methylene group, X2 is a carbon atom, Ar is a phenyl group, A compound in which R8 is a hydrogen atom, i is 0, and j is 1, for example, a copolymer of butylbornene and phenylethylnorbornene, a copolymer of hexylnorbornene and phenylethylnorbornene, a copolymer of decylnorbornene and phenylethylnorbornene, etc. Also good.
Further, the following may be used as the norbornene resin.

  In the formula (11), p6 / q6 may be 20 or less, preferably 15 or less, and more preferably about 0.1 to 10. Thereby, the effect including the repeating unit of multiple types of norbornene is exhibited.

The norbornene-based resin as described above preferably has a leaving group. Here, the leaving group is a group that is released by the action of an acid.
Specifically, those having at least one of an —O— structure, an —Si—aryl structure, and an —O—Si— structure in the molecular structure are preferable. Such an acid leaving group is released relatively easily by the action of a cation.

Among these, as the leaving group that causes a decrease in the refractive index of the resin by leaving, at least one of the -Si-diphenyl structure and the -O-Si-diphenyl structure is preferable.
For example, among the norbornene polymers represented by the formula (9), those in which X1 is an oxygen atom, X2 is a silicon atom, and Ar is a phenyl group have a leaving group.
Further, in the formula (4), there is a case where elimination occurs at the Si—O—X3 portion of the alkoxysilyl group.

For example, when the norbornene resin of formula (10) is used, it is presumed that the reaction proceeds as follows by the acid generated from the photoacid generator (denoted as PAG). Here, only the leaving group portion is shown, and the case where i = 1 is described.

  Furthermore, in addition to the structure of formula (10), the side chain may have an epoxy group. By using such a material, there is an effect that a film having excellent adhesion can be formed. A specific example is as follows.

The compound represented by the formula (12) is prepared by, for example, dissolving hexyl norbornene, diphenylmethyl norbornene methoxysilane (norbornene containing -CH2-O-Si (CH3) (Ph) 2 in the side chain) and epoxy norbornene in toluene, It can be obtained by solution polymerization using a Ni compound as a catalyst.

  When the cyclic olefin resin is used as a core material, it is not particularly limited, but at least one of a monomer having a cyclic ether group and an oligomer having a cyclic ether group and a photoacid generator may be used in combination. preferable. Thereby, the refractive index of the core material can be changed.

When using the above-mentioned cyclic olefin resin as the base polymer as the core material, it is preferable to use a monomer having a cyclic ether group and an oligomer having a cyclic ether group in combination. The monomer having a cyclic ether group and the oligomer having a cyclic ether group preferably have a refractive index different from that of the cyclic olefin resin and are compatible with the cyclic olefin resin. The refractive index difference between the monomer having a cyclic ether group and the oligomer having a cyclic ether group and the cyclic olefin resin is preferably 0.01 or more.
In addition, although the refractive index of the monomer which has the said cyclic ether group, and the oligomer which has a cyclic ether group may be higher than the said cyclic olefin resin, it is preferable that a refractive index is lower than the said cyclic olefin resin. As a result, when used in combination with the norbornene resin having a leaving group that lowers the refractive index of the resin by the aforementioned separation, the synergistic effect increases the refractive index difference between the core portion and the side cladding portion, thereby improving the light propagation performance. An excellent optical waveguide can be manufactured.

The monomer having a cyclic ether group and the oligomer having a cyclic ether group are preferably those that polymerize by ring opening in the presence of an acid. Considering the diffusibility of the monomer and oligomer, the molecular weight (weight average molecular weight) of the monomer and the molecular weight (weight average molecular weight) of the oligomer are preferably 100 or more and 400 or less, respectively.
The cyclic ether group has, for example, an oxetanyl group or an epoxy group. Such a cyclic ether group is preferable because it is easily opened by an acid.

  As the monomer having an oxetanyl group and the oligomer having an oxetanyl group, those selected from the following formulas (13) to (22) are preferable. By using these, there is an advantage that transparency in the vicinity of a wavelength of 850 nm is excellent and both flexibility and heat resistance are possible. These may be used alone or in combination.

  Especially, it is preferable to use Formula (15), (17), (18), (19), (22) from a viewpoint of ensuring the refractive index difference with the said cyclic olefin resin.

Furthermore, considering the point that there is a difference in refractive index from the cyclic olefin resin, the point that the molecular weight is small, the mobility of the monomer is high, and the point that the monomer does not easily volatilize, formulas (22) and (17) are used It is particularly preferable to do this.
Moreover, as a compound which has an oxetanyl group, the following formula | equation (23) and Formula (24) can also be used. Equation (23) can use TESOX (Toagosei) or the like, and Equation (24) can use OX-SQ (Toagosei) or the like.

On the other hand, examples of the monomer having an epoxy group and the oligomer having an epoxy group include the following. The monomer and oligomer having an epoxy group are polymerized by ring-opening in the presence of an acid.
As the monomer having an epoxy group and the oligomer having an epoxy group, those represented by the following formulas (25) to (30) can be used. Especially, it is preferable to use an alicyclic epoxy monomer (27)-(30) from a viewpoint that the distortion energy of an epoxy ring is large and is excellent in reactivity.
In addition, Formula (25) is epoxy norbornene, for example, EpNB (Promerus) can be used. Formula (26) is γ-glycidoxypropyltrimethoxysilane, and for example, Z-6040 (Toray Dow Corning Silicone) can be used. Further, formula (27) is 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and for example, E0327 (Tokyo Kasei) can be used.
Further, the formula (28) is 3,4-epoxycyclohexenylmethyl-3, '4'-epoxycyclohexenecarboxylate, and for example, CEL2021P (Daicel Chemical Industries) can be used. Further, the formula (29) is 1,2-epoxy-4-vinylcyclohexane, and CEL2000 (Daicel Chemical Industries) can be used.
Further, the formula (30) is 1,2: 8,9 diepoxy limonene, and for example, CEL3000 (Daicel Chemical Industries) can be used.

Further, as the monomer having a cyclic ether group and the oligomer having a cyclic ether group, a monomer having an oxetanyl group, an oligomer having an oxetanyl group, a monomer having an epoxy group, and an oligomer having an epoxy group may be used in combination. .
Monomers having an oxetanyl group and oligomers having an oxetanyl group have a slow initiation reaction but a fast growth reaction. On the other hand, a monomer having an epoxy group and an oligomer having an epoxy group have a fast initiation reaction for initiating polymerization, but have a slow growth reaction. Therefore, by using a monomer having an oxetanyl group, an oligomer having an oxetanyl group, a monomer having an epoxy group, and an oligomer having an epoxy group, when irradiated with light, the light irradiated portion and the unirradiated portion A refractive index difference can be generated reliably, and a core part and a side clad part can be formed in one film.

  The monomer having a cyclic ether group and the oligomer having a cyclic ether group are preferably 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the cyclic olefin resin. Of these, 2 parts by weight or more and 20 parts by weight or less are preferable. Thereby, the refractive index modulation between the core and the clad is possible, and there is an effect that both flexibility and heat resistance can be achieved.

  The photoacid generator is not particularly limited as long as it absorbs light energy to generate Bronsted acid or Lewis acid. For example, triphenylsulfonium trifluoromethanesulfonate, tris (4-t-butylphenyl) sulfonium. -Sulfonium salts such as trifluoromethanesulfonate, diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate, ammonium salts, phosphonium salts, diphenyliodonium trifluoromethanesulfonate, iodonium salts such as (triccumyl) iodonium-tetrakis (pentafluorophenyl) borate , Quinonediazides, diazomethanes such as bis (phenylsulfonyl) diazomethane, 1-phenyl-1- (4-methylphenyl) sulfo Nyloxy-1-benzoylmethane, sulfonic acid esters such as N-hydroxynaphthalimide-trifluoromethanesulfonate, disulfones such as diphenyldisulfone, tris (2,4,6-trichloromethyl) -s-triazine, 2- ( And compounds such as triazines such as 3.4-methylenedioxyphenyl) -4,6-bis- (trichloromethyl) -s-triazine. These photoacid generators can be used alone or in combination.

  The content of the photoacid generator is preferably 0.01 parts by weight or more and 0.3 parts by weight or less with respect to 100 parts by weight of the cyclic olefin resin. Especially, 0.02 weight part or more and 0.2 weight part or less are preferable. Thereby, there exists an effect of a reactive improvement.

  The core material may contain additives such as a sensitizer in addition to the components of the cyclic olefin resin, the monomer having a cyclic ether group, the oligomer having a cyclic ether group, and the photoacid generator. .

The sensitizer increases the sensitivity of the photoacid generator to light and is suitable for reducing the time and energy required for activation (reaction or decomposition) of the photoacid generator and for activating the photoacid generator. It has a function of changing the wavelength of actinic radiation to the wavelength.
Such a sensitizer is appropriately selected according to the sensitivity of the photoacid generator and the peak wavelength of absorption of the sensitizer, and is not particularly limited. For example, 9,10-dibutoxyanthracene (CAS No. 76275) is selected. -14-4), anthracenes, xanthones, anthraquinones, phenanthrenes, chrysene, benzpyrenes, fluoranthenes, rubrenes, pyrenes, indanthrines, thioxanthen-9-one Thioxanthen-9-ones, which are used alone or as a mixture.

  Specific examples of the sensitizer include 2-isopropyl-9H-thioxanthen-9-one, 4-isopropyl-9H-thioxanthen-9-one, 1-chloro-4-propoxythioxanthone, phenothiazine, and these Of the mixture. The content of the sensitizer in the photosensitive resin composition is preferably 0.01% by weight or more, more preferably 0.5% by weight or more, and further preferably 1% by weight or more. preferable. In addition, it is preferable that an upper limit is 5 weight% or less.

The core material using the cyclic olefin resin can be diluted with an appropriate solvent to obtain a resin varnish, and this resin varnish can be applied to a substrate and dried to obtain a core layer.
The solvent is not particularly limited, and examples thereof include toluene, xylene, mesitylene, tetrahydrofuran, cyclohexane, cyclohexanone, cyclopentane, cyclopentanone, methyl ethyl ketone, 2-heptanone, limonene, and decalin. You may use these solvent 1 type or in mixture of 2 or more types. The content of the cyclic olefin copolymer in the resin varnish is preferably 5 to 50% by weight in the resin varnish. Thereby, the viscosity suitable for application | coating can be provided to the said resin varnish, and application | coating performance can be improved. Especially, it is more preferable that it is 10 to 30 weight%. Thereby, when the said core material is apply | coated to a base material etc., the entrainment of a bubble is prevented and the viscosity suitable in order to obtain fixed thickness can be obtained.

As an embodiment of the present invention, an optical waveguide manufacturing method using the photosensitive resin composition of the present invention as the first cladding layer 1 and the core material using the cyclic olefin resin as the core layer 2 will be described below.
The photosensitive resin composition of this invention is apply | coated on the base material 6, and it hardens | cures by exposure, and the 1st clad layer 1 is obtained. At this time, the substrate is not particularly limited, but Si-wafer, a plastic film such as polyimide, glass, or the like is used.
A film for forming an optical waveguide is laminated on the first cladding layer 1 or a core material is applied to form the core layer 2. For example, when a core material using the above-described cyclic olefin resin is used, an optical waveguide can be generated according to the following principle.
A core material containing a cyclic olefin resin is applied to the first cladding layer 1 described above and dried to remove the solvent and form the core layer 2a. Further, as shown in FIG. 2, the core layer 2 a is irradiated with light 5 using a mask 4. Accordingly, by selectively irradiating the core layer 2a with the light 5, the side clad portion 22 can be formed in the irradiated region, and the core portion 21 can be formed in the non-irradiated region.
In the irradiated region (side clad portion 22), the acid generator in the photosensitive resin composition constituting the optical waveguide forming film generates an acid by light irradiation, whereby the first monomer is ring-opened to form a cation. Initiate polymerization. As a result, the force that eliminates the concentration gradient of the unreacted monomer in the matrix acts, and the first monomer partially diffuses from the unirradiated region (core portion 21) into the irradiated region and polymerizes. The refractive index of the portion 22) is relatively lower than the unirradiated region.
Moreover, the acid generated from the acid generator by light irradiation promotes the elimination of the leaving group that is a part of the side chain of the cyclic olefin resin. Thereby, since the high refractive index portion is detached, the refractive index of the irradiation region (side clad portion 22) is further lowered.
The core layer 2 is manufactured based on the principle as described above, and the irradiation region of the light 5 becomes the side cladding portion 22 and the non-irradiation region becomes the core portion 21.
Further, the second cladding layer 3 is laminated on the core layer 2. The second cladding layer 3 is not limited as long as it is a low refractive index material, and the photosensitive resin composition and the optical waveguide forming film of the present invention can also be used. The second cladding layer 3 can be formed by a general method such as laminating or coating.

  The optical waveguide 10 thus obtained can increase the refractive index difference between the core portion 21 and the first cladding layer 1, the second cladding layer 3, and the side cladding portion 22, thereby reducing optical loss. Thus, the optical waveguide 10 having excellent performance can be obtained.

  Hereinabove, the optical waveguide using the photosensitive resin composition of the present invention and the optical waveguide forming film as a clad material has been described. However, the photosensitive resin composition of the present invention and the optical waveguide forming film can also be used as a core material. However, the present invention is not limited to the clad material.

Next, the optical wiring, the opto-electric hybrid board, and the electronic device will be briefly described.
The optical wiring of the present invention has the optical waveguide 10 as described above. Thereby, since it is not necessary to go through development, RIE (reactive ion etching), or the like in the waveguide manufacturing process, the degree of freedom in processing can be improved.
Further, the opto-electric hybrid board of the present invention has electrical wiring and optical wiring having the optical waveguide 10 as described above. As a result, it is possible to improve EMI (electromagnetic wave interference), which has been a problem with conventional electrical wiring, and the signal transmission speed can be significantly improved as compared with the conventional case.
The electronic device of the present invention has the optical waveguide 10 as described above. Thereby, space saving can be achieved.
Specific examples of such an electronic device include a computer, a server, a mobile phone, a game device, a memory tester, and an appearance inspection robot.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this.

Example 1
(1) Preparation of photosensitive resin composition
48 g of CEL2021P (Daicel Chemical Industries), 12 g of OS-SQ-H (Toagosei), and 1.8 g of Adekaoptomer SP-170 (ADEKA) were uniformly dissolved, and then filtered through a PTFE filter having a pore size of 0.2 μm. A clean photosensitive resin composition 1 for a clad layer was prepared. Moreover, the refractive index of the photosensitive resin composition 1 was 1.52 (measurement wavelength; 633 nm) when measured using a METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).

(2) Synthesis of Cyclic Olefin Resin 7.2 g (40.1 mmol) of hexylnorbornene (HxNB), diphenylmethylnorbornenemethoxy in a glove box whose water and oxygen concentrations were both controlled to 1 ppm or less and filled with dry nitrogen 12.9 g (40.1 mmol) of silane was weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.
Next, 1.56 g (3.2 mmol) of Ni catalyst represented by the following formula (2) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip, and tightly plugged. Dissolved in.
When 1 mL of the Ni catalyst solution represented by the following formula (2) is accurately weighed with a syringe and quantitatively injected into the vial in which the above two types of norbornene are dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.
In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.
Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. By carrying out heat drying for 12 hours, a norbornene resin having a leaving group in the side chain was obtained. The molecular weight of the norbornene-based resin is Mw = 100,000 and Mn = 40,000 according to GPC measurement, and the molar ratio of each structural unit in the norbornene-based resin is 50 mol% of hexylnorbornene structural unit according to the identification by NMR, and diphenylmethylnorbornenemethoxy. The silane structural unit was 50 mol%. Further, the refractive index of the norbornene-based resin was 1.55 (measurement wavelength: 633 nm) as measured using METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).

(3) Preparation of core layer resin varnish 10 g of purified norbornene resin was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (Ciba Geigy), cyclohexyl oxetane monomer (formula (22) above) 2g, photoacid generator Rhodorsil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-) 72-2) (1.36E-2 g in 0.1 mL of ethyl acetate) was added and dissolved uniformly, and then filtered through a 0.2 μm PTFE filter to prepare a clean resin varnish for the core layer.

(4) Production of optical waveguide (production of first clad layer)
After the photosensitive resin composition 1 is uniformly applied on a silicon wafer with a doctor blade, the applied whole surface is irradiated with 700 mJ of ultraviolet light and heated at 150 ° C. for 10 minutes in a dryer to cure the coating film. A first cladding layer was formed. The formed first cladding layer 1 had a thickness of 20 μm, was colorless and transparent, and had a refractive index of 1.52 (measurement wavelength: 633 nm).

(Manufacture of core and side cladding)
The above-mentioned resin varnish for core layer obtained by preparation was uniformly applied on the first clad layer with a doctor blade, and then placed in a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm 2. The mask was removed, and heating was performed in three stages of 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour in a dryer. After heating, a core layer with a very clear waveguide pattern was confirmed.

(Preparation of the second cladding layer)
After the photosensitive resin composition 1 is uniformly coated on the core layer with a doctor blade, the coated whole surface is irradiated with 700 mJ of ultraviolet light and heated in a dryer at 150 ° C. for 10 minutes to cure the coating film. Thus, a second cladding layer was formed.

(5) Evaluation (Evaluation of optical waveguide loss)
The light emitted from the 850 nm VCSEL (surface emitting laser) was introduced into the obtained optical waveguide via a 50 μmφ optical fiber, and received by the 200 μmφ optical fiber to measure the light intensity. In addition, the cutback method was employ | adopted for the measurement. When the waveguide length was plotted on the horizontal axis and the insertion loss plotted on the vertical axis, the measured values were neatly arranged on a straight line, and the propagation loss could be calculated as 0.039 dB / cm from the slope.

(Near-field image)
After aligning the optical axis so that light is incident on an arbitrary core portion of the optical waveguide, the light is incident, and on the exit side of the optical waveguide, the core portion and the core portion are transmitted by an infrared vidicon camera through an objective lens. The near-field image of the range including the core part on both sides of was taken. In the near-field image, the emitted propagating light is visualized, and the higher the intensity of the emitted light, the lighter the brightness is, and the lighter the color is, the lower the intensity of the emitted light is, and the light does not propagate at all. The part is shown in black.
> From the near-field image, the optical waveguide confirmed the emitted light only in the core part where the propagating light was incident, and confirmed that there was no leakage of the propagating light in the adjacent core part and the adjacent side cladding part. .

(Example 2)
In the preparation of the photosensitive resin composition, 57 g of CEL2021P (Daicel Chemical Industries), 3 g of OS-SQ (Toagosei), and 1.8 g of Adekaoptomer SP-170 (ADEKA) were uniformly dissolved, and the pore size was 0.2 μm. Filtration was performed using a PTFE filter, and a photosensitive resin composition 2 for a clean cladding layer was prepared. The refractive index of the photosensitive resin composition 2 was 1.52 (measurement wavelength: 633 nm) when measured using METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).
The same procedure as in Example 1 was performed except that the photosensitive resin composition 2 was used instead of the photosensitive resin composition 1. The propagation loss of the obtained optical waveguide was 0.051 dB / cm. Further, when the near-field image was confirmed, the emitted light was confirmed only in the core part where the propagation light was incident, and it was confirmed that there was no leakage of the propagation light in the adjacent core part and the adjacent side cladding part.

(Example 3)
In the preparation of the photosensitive resin composition, 57 g of ERLX-4360 (Synasia), 3 g of OS-SQ (Toagosei), and 1.8 g of Adekaoptomer SP-170 (ADEKA) were uniformly dissolved, and then the pore size was 0.2 μm. Filtration was performed using a PTFE filter, to prepare a photosensitive resin composition 3 for a clean cladding layer. The refractive index of the photosensitive resin composition 3 was 1.52 (measurement wavelength: 633 nm) when measured using METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).
The same procedure as in Example 1 was performed except that the photosensitive resin composition 3 was used instead of the photosensitive resin composition 1. The propagation loss of the obtained optical waveguide was 0.053 dB / cm. Further, when the near-field image was confirmed, the emitted light was confirmed only in the core part where the propagation light was incident, and it was confirmed that there was no leakage of the propagation light in the adjacent core part and the adjacent side cladding part.

(Comparative Example 1)
In the preparation of the photosensitive resin composition, 48 g of CEL2081 (Daicel Chemical Industries), 12 g of OS-SQ (Toagosei), and 1.8 g of Adekaoptomer SP-170 (ADEKA) were uniformly dissolved, and the pore size was 0.2 μm. Filtration was performed using a PTFE filter, and a photosensitive resin composition 4 for a clean clad layer was prepared. The refractive index of the photosensitive resin composition 4 was 1.52 (measurement wavelength: 633 nm) as measured using METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).
The same procedure as in Example 1 was performed except that the photosensitive resin composition 4 was used instead of the photosensitive resin composition 1. The propagation loss of the obtained optical waveguide was found to be 0.152 dB / cm, which is poor in optical characteristics. This is probably because the optical waveguide obtained as shown in the near-field image has a significant leakage of light to the side cladding, and the difference in refractive index at the interface between the core and the side cladding is not sufficient. The resin varnish for the core layer penetrates into the first clad layer produced with the photosensitive resin composition 4, and the difference in refractive index between the side clad portion and the core portion is reduced, resulting in a deterioration in propagation loss. Conceivable.

(Comparative Example 2)
In the preparation of the photosensitive resin composition, EMI-3580 (Uvix Corporation) was used as the photosensitive resin composition 5. The refractive index of the photosensitive resin composition was 1.48 (measurement wavelength: 633 nm) as measured using METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).
The same procedure as in Example 1 was performed except that the photosensitive resin composition 5 was used instead of the photosensitive resin composition 1. The propagation loss of the obtained optical waveguide was found to be 0.136 dB / cm, which is poor in optical characteristics. From the near-field image, it was confirmed that light leaked in the lower part of the core layer of the obtained waveguide. Therefore, the resin varnish for the core layer was prepared from the photosensitive resin composition 5 as in Comparative Example 1. It penetrates the clad layer, and the difference in refractive index between the side clad part and the core part becomes small, and it is considered that the propagation loss is deteriorated as a result.

(Comparative Example 3)
In the preparation of the photosensitive resin composition, V-9520 (DIC Corporation) was diluted to rc = 20% with mesitylene as a solvent and used as the photosensitive resin composition 6. The refractive index of the photosensitive resin composition was 1.48 (measurement wavelength: 633 nm) as measured using METRICON model 2010 (manufactured by Seki Technotron Co., Ltd.).
The same procedure as in Example 1 was performed except that the photosensitive resin composition 6 was used instead of the photosensitive resin composition 1. As a result, it was found that the propagation loss of the obtained optical waveguide was 0.573 dB / cm and the optical characteristics were very bad. It is considered that the resin varnish for the core layer penetrates into the first clad layer made of the photosensitive resin composition 6 as in Comparative Example 1, and the difference in refractive index between the side clad portion and the core portion is reduced. . Alternatively, since the photosensitive resin composition 6 contains a component that supplements the acid of the core layer, the refractive index of the side cladding portion is not sufficiently lowered, and the expression of the optical waveguide is inhibited.

  Table 1 shows the results obtained for the optical waveguides obtained in each of the examples and comparative examples.

As is apparent from Table 1, Examples 1 to 3 showed low optical loss and excellent optical waveguide performance. On the other hand, Comparative Examples 1-3 were inferior in propagation loss compared with Examples 1-3. This is because the crosslink density of the clad layers of Examples 1 to 3 is high, so that components (acid, monomer, etc.) contained in the core layer are prevented from penetrating into the clad layer, and the refractive indexes of the side clad portion and the core portion. This is thought to be because the difference could be made sufficiently.

1 1st cladding layer 2 core layer 2a core layer (before light 5 irradiation)
21 Core part 22 Side clad part 3 Second clad layer 4 Mask 5 Light 6 Substrate 10 Optical waveguide

Claims (12)

A photosensitive resin composition for forming an optical waveguide, include an alicyclic epoxy monomer having two or more (A) functional groups, and (B) silsesquioxane, and (C) an acid generator A photosensitive resin composition characterized by the above.
The (A) alicyclic epoxy monomer having two or more functional groups is (3′-4′-Epoxycyclohexane) methyl 3′-4′-Epoxycyclohexyl-carboxylate, (3′-4′-Epoxycyclohexane) methyl 3 ′. The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition is selected from the group consisting of -4'-Epoxycyclohexyl-carboxylate modified-caprolactone. The silsesquioxane to a photosensitive resin composition according to claim 1 or 2 is represented by the following formula (24).

The weight ratio (A) / (B) of the alicyclic epoxy monomer having two or more functional groups (A) and the oxetane monomer having two or more functional groups (B) is 99/1 to 20/80. The photosensitive resin composition according to any one of claims 1 to 3 . For forming an optical waveguide film photosensitive resin composition is characterized in that it is used according to any one of claims 1 to 4. An optical waveguide formed using the optical waveguide forming film according to claim 5 . The optical waveguide according to claim 6 , which has a core portion formed using a cyclic olefin resin. The optical waveguide according to claim 7 , wherein the cyclic olefin resin is a norbornene resin. The optical waveguide according to claim 8 , wherein the norbornene resin is represented by the following formula (10).

Optical wiring, characterized in that it comprises an optical waveguide according to any one of claims 6 to 9. An opto-electric hybrid board comprising electrical wiring and the optical wiring according to claim 10 . An electronic apparatus comprising the optical waveguide according to any one of claims 6 to 11.

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