Optical waveguide and optical member having same

Abstract

Provided is an optical waveguide provided with a core for transmitting light and a cladding section having a lower refractive index than the core, the cladding section having a lower cladding section present on one surface of the core, and in a cross-sectional shape of the core in a direction perpendicular to the light transmission direction, the refractive index of the cladding section is less than the refractive index of the cladding section. When the direction of a line where the core and the lower cladding section are in contact is defined as the width direction and the direction perpendicular to the width direction is defined as the thickness direction, (i) the maximum length in the width direction in a cross section of the core is defined as L [[mu] m] and the maximum length in the thickness direction is defined as H [[mu] m], H / L is 0.4-3; or (ii) the taper angle is 50-130 degrees (inclusive) when the taper angle of the core portion is defined as the angle formed by the lower cladding and a tangent line to the core-side portion corresponding to a length equivalent to 1 / 2 of the maximum length in the thickness direction of the core portion; at least one of the core part and the cladding part is composed of a cured product obtained by curing a composition containing an organopolysiloxane having a specific structure.

Description

Technical Field

[0001] This invention relates to optical waveguides and optical components having optical waveguides. Background Technology

[0002] In fields such as communications, with the increasing speed of communication, the transmission of optical signals using optical waveguides has attracted attention (Patent Document 1). In particular, optical waveguides made of polymers can be fabricated using low-temperature processing techniques such as photolithography, and are easy to mount onto substrates, and are therefore under various development.

[0003] For example, Patent Document 1 discloses a polymer optical waveguide in which the height and width of the core constituting the waveguide are within a specific range, and attempts have been made to provide a polymer optical waveguide that reduces the transmission loss of optical signals.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2018 / 168783 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the reduction in transmission loss of optical signals in the aforementioned prior art is not sufficient, and further reduction in transmission loss is required. Depending on the structure of the optical waveguide, polarization-dependent loss in optical transmission may also increase, and the transmission loss varies depending on the polarization state of the incident light, thus requiring improvement.

[0009] The problem with this invention is to provide an optical waveguide with reduced transmission loss and low polarization-dependent loss.

[0010] Solution for solving the problem

[0011] The inventors conducted in-depth research and found that if an optical waveguide has a core and a lower cladding portion connected to a part of the core with a refractive index less than that of the core, and the core has a specific cross-sectional shape, then the transmission loss is reduced and the polarization-dependent loss is lowered, thus completing the present invention.

[0012] The main points of this invention are as follows.

[0013] (1) An optical waveguide comprising a core for transmitting light and a cladding portion having a refractive index lower than that of the core,

[0014] The cladding portion has a lower cladding portion that is connected to a portion of the core portion.

[0015] In the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, if the direction of the line connecting the core and the lower cladding is defined as the width direction, the direction perpendicular to the width direction is defined as the thickness direction, and the maximum length in the width direction of the core cross-section is defined as L [μm], and the maximum length in the thickness direction is defined as H [μm], then...

[0016] H / L is 0.4 to 3.

[0017] At least one of the core and the cladding is composed of a cured product formed by curing a composition containing an organopolysiloxane having polymerizable functional groups as represented by the following formula [1].

[0018] (R) 1 R 2 R 3 SiO 1 / 2 ) M1 (R) 4 R 5 R 6 SiO 1 / 2 ) M2

[0019] (R) 7 R 8 SiO 2 / 2 ) D1 (R) 9 R 6 SiO 2 / 2 ) D2

[0020] (R) 10 SiO 3 / 2 ) T1 (R) 6 SiO 3 / 2 ) T2 (SiO) 4 / 2 ) Q

[0021] (O) 1 / 2 R 11 ) Y1 (O) 1 / 2 R 6 ) Y2 ...[1]

[0022] In formula [1], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0023] R 1 ~R 3 R7 R 8 R 10 and R 11 It does not contain polymerizable functional groups.

[0024] R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other.

[0025] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0≤Q

[0026] 0 <M2+D2+T2、

[0027] 0 <D1+D2+T1+T2+Q、

[0028] M1+M2+D1+D2+T1+T2+Q=1].

[0029] (2) An optical waveguide comprising a core for transmitting light and a cladding portion having a refractive index lower than that of the core,

[0030] The cladding portion has a lower cladding portion that is connected to a portion of the core portion.

[0031] In the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, the direction of the line connecting the core and the lower cladding is defined as the width direction, the direction perpendicular to the width direction is defined as the thickness direction, and the angle formed by the tangent of the core side portion whose maximum length relative to the thickness direction is equivalent to 1 / 2 of the core portion and the lower cladding portion is defined as the cone angle of the core, wherein the cone angle is 50° or more and 130° or less.

[0032] At least one of the core and the cladding is composed of a cured product formed by curing a composition containing an organopolysiloxane having polymerizable functional groups as represented by the following formula [1].

[0033] (R) 1 R 2 R 3 SiO 1 / 2 ) M1 (R) 4 R 5 R 6 SiO 1 / 2 ) M2

[0034] (R) 7 R 8 SiO 2 / 2 ) D1 (R) 9 R 6 SiO 2 / 2 )D2

[0035] (R) 10 SiO 3 / 2 ) T1 (R) 6 SiO 3 / 2 ) T2 (SiO) 4 / 2 ) Q

[0036] (O) 1 / 2 R 11 ) Y1 (O) 1 / 2 R 6 ) Y2 ...[1]

[0037] In formula [1], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0038] R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymerizable functional groups.

[0039] R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other.

[0040] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0≤Q

[0041] 0 <M2+D2+T2、

[0042] 0 <D1+D2+T1+T2+Q、

[0043] M1+M2+D1+D2+T1+T2+Q=1].

[0044] (3) The optical waveguide according to (1) or (2) above, wherein the refractive index difference between the core and the cladding is 0.005 or more and 0.05 or less.

[0045] (4) The optical waveguide according to any one of (1) to (3) above, wherein, in the cross-sectional shape of the core in the direction perpendicular to the optical transmission direction, the length of the lower cladding portion in the thickness direction is 1 μm or more.

[0046] (5) The optical waveguide according to any one of (1) to (4) above, wherein the cladding portion has an upper cladding portion that exists in the core and is not connected to the lower cladding portion.

[0047] (6) The optical waveguide according to any one of (1) to (5) above, wherein the core has a refractive index of 1.400 or more and 1.520 or less at a wavelength of 1300 nm.

[0048] (7) The optical waveguide according to any one of (1) to (6) above, wherein the organopolysiloxane having polymerizable functional groups is represented by the following formula [2].

[0049] (R) 1 R 2 R 3 SiO 1 / 2 ) M1 (R) 4 R 5 R 6 SiO 1 / 2 ) M2

[0050] (R) 7 R 8 SiO 2 / 2 ) D1 (R) 9 R 6 SiO 2 / 2 ) D2

[0051] (R) 10 SiO 3 / 2 ) T1 (R) 6 SiO 3 / 2 ) T2 (SiO) 4 / 2 ) Q

[0052] (O) 1 / 2 R 11 ) Y1 (O) 1 / 2 R 6 ) Y2 ...[2]

[0053] In formula [2], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0054] R 1 ~R 3 R7 R 8 R 10 and R 11 It does not contain polymerizable functional groups.

[0055] R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other.

[0056] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2,

[0057] 0 <Q、

[0058] 0 <M2+D2+T2、

[0059] M1+M2+D1+D2+T1+T2+Q=1].

[0060] (8) The optical waveguide according to any one of (1) to (6) above, wherein the organopolysiloxane having polymerizable functional groups is represented by the following formula [3].

[0061] (R) 1 R 2 R 3 SiO 1 / 2 ) M1 (R) 4 R 5 R 6 SiO 1 / 2 ) M2

[0062] (R) 7 R 8 SiO 2 / 2 ) D1 (R) 9 R 6 SiO 2 / 2 ) D2

[0063] (R) 10 SiO 3 / 2 ) T1 (R) 6 SiO 3 / 2 ) T2

[0064] (O) 1 / 2 R 11 ) Y1 (O) 1 / 2 R 6 ) Y2 ...[3]

[0065] In formula [3], R 1 ~R5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0066] R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymerizable functional groups.

[0067] R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other.

[0068] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2,

[0069] 0 <D1+D2+T1+T2、

[0070] 0 <M2+D2+T2、

[0071] M1+M2+D1+D2+T1+T2=1].

[0072] (9) An optical waveguide according to any one of (1) to (6) above, wherein, in the formula [1], 0.02≤Y1≤0.25.

[0073] (10) An optical waveguide according to any one of (1) to (6) above, wherein, in the formula [1], 0 <M2+D2+T2≤0.25。

[0074] (11) An optical waveguide according to any one of (1) to (6) above, wherein, in the formula [1], 0.12 <M2+D2+T2≤0.25。

[0075] (12) The optical waveguide according to (7) above, wherein in the formula [2], 0.02≤Y1≤0.25.

[0076] (13) The optical waveguide according to (7) or (12) above, wherein, in the formula [2], 0.04≤Q.

[0077] (14) According to the optical waveguide described in (8) above, wherein, in the formula [3], 0 <D1+D2。

[0078] (15) The optical waveguide according to (8) or (14) above, wherein, in the formula [3], 0.1 <D1+D2。

[0079] (16)The optical waveguide according to (8), (14), or (15) above, wherein in the formula [3], 0 < D1.

[0080] (17)The optical waveguide according to any one of (8), (14) to (16) above, wherein in the formula [3], 0.02 ≤ Y1 ≤ 0.25.

[0081] (18)The optical waveguide according to any one of (8), (14) to (17) above, wherein in the formula [3], 0 < T1 + T2.

[0082] (19)The optical waveguide according to any one of (8), (14) to (18) above, wherein in the formula [3], 0 < D1 + D2 and 0 < T1 + T2.

[0083] (20)The optical waveguide according to any one of (1) to (19) above, wherein the R 6 contains a polymerizable alkenyl group.

[0084] (21)The optical waveguide according to any one of (1) to (20) above, wherein the R 6 contains an acryloyl group and / or a methacryloyl group.

[0085] (22)The optical waveguide according to any one of (1) to (21) above, wherein the organopolysiloxane having a polymerizable functional group does not contain an aromatic structure.

[0086] (23)The optical waveguide according to any one of (1) to (22) above, wherein the R 6 is acryloxypropyl and / or methacryloxypropyl.

[0087] (24)The optical waveguide according to any one of (1) to (23) above is for single mode.

[0088] (25)An optical member having the optical waveguide according to any one of (1) to (24) above.

[0089] Advantages of the Invention

[0090] According to the present invention, it is possible to provide an optical waveguide with reduced transmission loss and low polarization-dependent loss, and an optical member having the optical waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 is a diagram showing a configuration example of a cross-sectional shape of an optical waveguide according to one aspect of the present invention.

[0092] Description of Reference Numerals

[0093] 10: Optical waveguide;

[0094] 20: Core;

[0095] 30: Cladding portion;

[0096] 31: Upper cladding portion;

[0097] 32: Lower cladding portion:

[0098] 40: Cone angle.

[0099] Figure 2 This is a diagram illustrating an example of the cone angle of the core in an optical waveguide according to another embodiment of the present invention. Detailed Implementation

[0100] Hereinafter, embodiments of the present invention (hereinafter sometimes referred to as this embodiment) will be described in detail, but the following description is only an example of the embodiments and the present invention is not limited thereto.

[0101] In this invention, "(meth)acryl" means "either or both of acryl and methacryl".

[0102] In this invention, the numerical range represented by “~” refers to the range that includes the values ​​recorded before and after “~” as the lower limit and upper limit.

[0103] In this invention, the weight-average molecular weight refers to the weight-average molecular weight (Mw) of polystyrene obtained by gel permeation chromatography (GPC).

[0104] [Optical waveguide]

[0105] The optical waveguide of the present invention will now be described with reference to the accompanying drawings.

[0106] Figure 1 This is a diagram illustrating one configuration example of the cross-sectional shape of the optical waveguide of the present invention. Figure 1 In this context, the direction of light transmission is either from the front of the paper to the inside, or from the inside of the paper to the front; that is, Figure 1 It is a diagram showing the cross-sectional shape of an optical waveguide in a direction perpendicular to the direction of light transmission.

[0107] Figure 1 The optical waveguide 10 shown has a core 20 and a cladding portion 30 with a refractive index lower than that of the core 20. The cladding portion 30 consists of at least a portion of the core 20 ( Figure 1 The lower cladding portion 32, which is connected to the lower part of the core, and the portion of the core 20 that is not connected to the lower cladding portion (the middle part of the core). Figure 1 It is composed of the upper cladding portion 31 of the core (the upper part and the left and right parts).

[0108] In this invention, a lower cladding layer is provided that is in contact with a portion of the core, and an upper cladding layer is provided on the portion of the core that is not in contact with the lower cladding layer. However, for convenience, only the terms "lower cladding layer" and "upper cladding layer" are used. For example, in one aspect of this invention, the lower portion of the covered core may be referred to as the lower cladding layer, and the upper portion of the covered core may be referred to as the upper cladding layer; in other aspects, the reverse may also be used. Furthermore, in another aspect of this invention, the two may be integrated.

[0109] In the optical waveguide 10, the refractive index difference between the core and the cladding is preferably 0.005 or more and 0.05 or less. By reducing the refractive index difference between the core and the cladding, it is easier to generate a single-mode guided wave in the optical waveguide 10. Furthermore, by having a refractive index difference between the core and the cladding, there is a tendency to reduce light scattering generated when bending the optical waveguide.

[0110] The lower limit of the refractive index difference is more preferably 0.01 or more. Furthermore, the upper limit is more preferably 0.03 or less. For example, in the case of near-infrared single-mode light signals, the above-mentioned refractive index difference is preferably 0.01 to 0.05, more preferably 0.01 to 0.04, and even more preferably 0.01 to 0.03.

[0111] exist Figure 1 In the cross-sectional shape of the optical waveguide shown, L represents the maximum length [μm] of the core 20 in the width direction when the direction of the line connecting the core 20 and the lower cladding 32 is set as the width direction, and H represents the maximum length [μm] of the core 20 in the thickness direction when the direction perpendicular to the width direction is set as the thickness direction (hereinafter, sometimes only L and H are referred to).

[0112] The optical waveguide of the first embodiment of the present invention (hereinafter, sometimes also referred to as the optical waveguide of this first embodiment) requires an H / L ratio in the range of 0.4 to 3. By making the H / L within the above range, the transmission loss difference between orthogonally polarized waves and parallel polarized waves is reduced, thereby reducing polarization-dependent loss.

[0113] H / L is preferably 0.5 or more, more preferably 0.7 or more, preferably 2 or less, and more preferably 1.5 or less.

[0114] The optical waveguide of this first embodiment can also have different H locations, provided that the H / L ratio meets the above-mentioned range. For example, the H may be different at one end and the other end of the optical waveguide. Furthermore, the H may be different at both ends of the optical waveguide and at the middle location in the optical transmission direction of the core.

[0115] The optical waveguide of this first embodiment can also have different L locations, provided that the H / L ratio meets the above-mentioned range. For example, the L can be different at one end and the other end of the optical waveguide. Alternatively, the L can be different at both ends of the optical waveguide and at the middle location in the optical transmission direction of the core.

[0116] The optical waveguide of the second aspect of the present invention (hereinafter, sometimes also referred to as the optical waveguide of this second aspect) requires that, in the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, the direction of the line connecting the core and the lower cladding portion is set as the width direction, the direction perpendicular to the width direction is set as the thickness direction, and the angle formed by the tangent of the core side portion whose maximum length relative to the thickness direction of the core is equivalent to 1 / 2 of the length and the lower cladding portion is set as the cone angle of the core, and this cone angle has a constant value. For example, when the core side portion (i) whose maximum length relative to the thickness direction of the core is equivalent to 1 / 2 of the length is a straight line, the tangent of the core side portion, that is, the angle formed by the core side portion (i) and the lower cladding portion, becomes the cone angle of the core. When the core side portion (ii) whose maximum length relative to the thickness direction of the core is equivalent to 1 / 2 of the length is a curve, the angle formed by the tangent of the core side portion (ii) and the lower cladding portion becomes the cone angle of the core.

[0117] In the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, if the left and right cone angles of the core are different, in this solution, the smaller angle is set as the cone angle of the core.

[0118] For example, in Figure 2 In the cross-sectional shape of the optical waveguide shown, a point A is taken at a point on the side of the core 20 (i.e., the aforementioned core side portion (i)) at a length equivalent to half the thickness of the core 20, relative to the maximum length H in the thickness direction. The angle 40 formed by the straight line tangent to the core 20 at point A and the lower cladding portion 32 is the left-side cone angle of the core 20. Although not described in detail, this left-side cone angle and Figure 2 When the cone angle on the right side of the core shown (the angle formed by the tangent of the core side (ii) and the lower cladding becomes the cone angle of each core) is different, as described above, the smaller angle becomes the cone angle of the core 20.

[0119] In the optical waveguide of this second scheme, the aforementioned cone angle needs to be greater than 50° and less than 130°. If the aforementioned cone angle is outside the aforementioned range, the transmission loss difference between orthogonally polarized waves and parallel polarized waves cannot be reduced, and the reduction of polarization-dependent loss cannot be achieved.

[0120] The lower limit of the aforementioned cone angle is preferably 70° or more, more preferably 80° or more, and the upper limit is preferably 110° or less, more preferably 100° or less.

[0121] In this second embodiment, the optical waveguide can have portions with different maximum thickness lengths H in the core direction, provided that the cone angle meets the aforementioned range. For example, the maximum thickness length H of the core can be different at one end and the other end of the optical waveguide. Alternatively, the maximum thickness length H of the core can be different at both ends of the optical waveguide and at the middle portion of the core in the optical transmission direction.

[0122] The optical waveguide of this second embodiment can have different L positions as long as the cone angle meets the above-mentioned range. For example, L can be different at one end and the other end of the optical waveguide. Alternatively, L can be different at both ends of the optical waveguide and at the middle position in the optical transmission direction of the core.

[0123] In the optical waveguides of the first and second embodiments of the present invention (hereinafter, sometimes referred to as the waveguides of these two embodiments), H is preferably 1.0 to 10 μm, and L is preferably 1.0 to 15 μm. If H and L are within the above ranges, it is not easy to transmit higher-order modes of light at wavelengths of 1310 nm and 1550 nm, and there is a tendency to transmit light in single-mode. H is more preferably 3 to 10 μm, and even more preferably 3 to 8 μm. L is more preferably 3 to 10 μm, and even more preferably 3 to 8 μm.

[0124] The values ​​of H and L can be determined by cutting the optical waveguide and observing the cross-sectional shape of the core, for example, by using a scanning electron microscope (SEM).

[0125] In the case of an optical waveguide composed of multiple cores arranged side-by-side with respect to the cladding portion, there may be some cores whose maximum length (H) in the thickness direction and maximum length (L) in the width direction do not satisfy the above-mentioned ranges. Specific examples of cores that do not satisfy the above-mentioned ranges include cores used for positioning during the connection of the optical waveguide.

[0126] The length of the lower cladding portion 32 in the thickness direction is preferably 1 μm or more, more preferably 5 μm or more, and particularly preferably 10 μm or more.

[0127] By setting the length of the lower cladding portion 32 in the thickness direction to 1 μm or more, light diffusion outward from the core can be effectively suppressed, thereby reducing transmission loss.

[0128] To enable single-mode waveguided operation within the core, it is preferable to have an upper cladding portion 31 on the upper part and left and right sides of the core 20. In the absence of the upper cladding portion 31, air acts as the upper cladding, but due to the large difference in refractive index between the core and air, single-mode waveguided operation is difficult.

[0129] When connecting an optical waveguide to a quartz fiber, a small difference in refractive index between the core of the optical waveguide and the core of the quartz fiber can suppress end-face reflection at the connection point. Typically, when the refractive index of the quartz fiber core at near-infrared wavelengths is around 1.4 to 1.5, and the refractive index of the optical waveguide core at near-infrared wavelengths is 1.40 to 1.50, more preferably 1.42 to 1.48, end-face reflection tends to be suppressed. From the viewpoint of suppressing end-face reflection of near-infrared light, the refractive index of the core at a wavelength of 1300 nm is preferably 1.400 or higher and 1.520 or lower, more preferably 1.420 or higher and 1.500 or lower, and particularly preferably 1.440 or higher and 1.480 or lower.

[0130] (Transmission loss)

[0131] The optical waveguides of these two schemes are characterized by reduced transmission loss, particularly at near-infrared wavelengths, preferably below 0.40 dB / cm, more preferably below 0.35 dB / cm, even more preferably below 0.32 dB, and still more preferably below 0.30 dB / cm. The transmission loss is measured according to the method described in the embodiments below.

[0132] In the optical waveguides of these two schemes, the constituent materials of the core and the cladding need to be materials that generate a difference in refractive index in such a way that the refractive index of the cladding is lower than that of the core. At least one of the core and the cladding is composed of a cured product formed by curing a composition containing an organopolysiloxane (hereinafter, sometimes simply referred to as "organopolysiloxane") having polymerizable functional groups represented by the following formula [1].

[0133] (R) 1 R 2 R 3 SiO 1 / 2 ) M1 (R) 4 R 5 R 6 SiO 1 / 2 ) M2

[0134] (R) 7 R 8 SiO 2 / 2 ) D1 (R) 9 R 6 SiO 2 / 2 ) D2

[0135] (R) 10 SiO 3 / 2 ) T1 (R) 6 SiO 3 / 2) T2 (SiO) 4 / 2 ) Q

[0136] (O) 1 / 2 R 11 ) Y1 (O) 1 / 2 R 6 ) Y2 ...[1]

[0137] In the above formula [1], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0138] R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymerizable functional groups.

[0139] R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other.

[0140] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0≤Q

[0141] 0 <M2+D2+T2、

[0142] 0 <D1+D2+T1+T2+Q、

[0143] M1+M2+D1+D2+T1+T2+Q=1.

[0144] In general formula [1], the coefficients M1, M2, D1, D2, T1, T2, and Q represent the proportions of each structure (based on the number of moles) when M1+M2+D1+D2+T1+T2+Q=1. Furthermore, in general formula [1], the coefficients Y1 and Y2 represent the proportions of each structure (based on the number of moles) when M1+M2+D1+D2+T1+T2+Q=1. 1 / 2 R 11 ) and (O 1 / 2 R 6 The relative proportion of (based on moles) of ).

[0145] In general formula [1], coefficients M1 and M2 represent so-called M-unit silicon (SiO2) in which one oxygen atom is bonded to a silicon atom. 1 / 2), (hereinafter sometimes referred to only as "M unit"). Similarly, D1 and D2 represent the proportion of D unit silicon (SiO 2 / 2 ), (hereinafter sometimes referred to only as "D unit"), T1 and T2 represent the proportion of T unit silicon (SiO 3 / 2 ), (hereinafter sometimes referred to only as "T unit"), and Q represents the proportion of Q unit silicon (SiO 4 / 2 ), (hereinafter sometimes referred to only as "Q unit").

[0146] M2, D2, and T2 respectively represent the proportions of M unit, D unit, and T unit in which an organic group containing a polymerizable functional group, i.e., R, is bonded to a silicon atom. 6 That is, the proportions of M unit, D unit, and T unit containing an organic group containing a polymerizable functional group.

[0147] Y1 represents the content ratio of a structure having a group selected from the group consisting of an organic group and a hydrogen atom and not containing a polymerizable functional group, specifically an alkoxy group or a silanol group, and Y2 represents the content ratio of an organic group containing a polymerizable functional group bonded to silicon.

[0148] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0≤Q means that M1, D1, T1, Y1, Y2, and Q are each 0 or more and can also be 0, that is, it means that this structural unit may not be present.

[0149] 0<M2 + D2 + T2 means that the organopolysiloxane has at least any one of M unit, D unit, and T unit in which an organic group containing a polymerizable functional group, i.e., R, is bonded to a silicon atom. 6 That is, at least any one of M unit, D unit, and T unit containing an organic group containing a polymerizable functional group.

[0150] 0<D1 + D2 + T1 + T2 + Q means that the organopolysiloxane has at least any one of D unit, T unit, and Q unit.

[0151] M1 + M2 + D1 + D2 + T1 + T2 + Q = 1 means that the total proportion of M unit, D unit, T unit, and Q unit is 1.

[0152] <M2 + D2 + T2>

[0153] In the organopolysiloxane represented by formula [1], when 0 < M2 + D2 + T2, the organopolysiloxane contains a polymerizable functional group, and a cured product can be easily obtained using the composition containing a polymerization initiator described later. If the content ratio of the polymerizable functional group is too small, poor curing may occur when producing the cured product, and in addition, the compatibility with other components added to the composition containing the organopolysiloxane described later will deteriorate. From the above viewpoints, 0.10 ≤ M2 + D2 + T2 is preferred, and 0.12 ≤ M2 + D2 + T2 is more preferred.

[0154] On the other hand, in the present invention, regarding the upper limit of M2 + D2 + T2, as described below, there are two implementation modes in two schemes.

[0155] In the first implementation mode, when the ratio of M2 + D2 + T2 is too large, considering that the content of the polymerizable functional group becomes large and the crosslinking density of the cured product becomes high and thus it is likely to become brittle, it is preferred that M2 + D2 + T2 ≤ 0.75, and more preferably M2 + D2 + T2 ≤ 0.60.

[0156] In the second implementation mode, in addition to the above effects, from the viewpoints of making an organopolysiloxane with excellent heat resistance and having a lower refractive index in the near-infrared wavelength region, it is preferred that M2 + D2 + T2 ≤ 0.25, and more preferably M2 + D2 + T2 ≤ 0.20.

[0157] As described above, in the first implementation mode, it is preferred that 0.10 ≤ M2 + D2 + T2 ≤ 0.75, and further preferably 0.12 ≤ M2 + D2 + T2 ≤ 0.60. In the second implementation mode, it is preferred that 0 < M2 + D2 + T2 ≤ 0.25, more preferably 0.10 ≤ M2 + D2 + T2 ≤ 0.25, further preferably 0.12 ≤ M2 + D2 + T2 ≤ 0.25, still further preferably 0.12 < M2 + D2 + T2 ≤ 0.25, and still further preferably 0.12 < M2 + D2 + T2 ≤ 0.20.

[0158] <Q unit>

[0159] The Q unit is the form in which silicon is most oxidized. By including it in the structure of the organopolysiloxane, the heat resistance of the cured product can be improved. The Q unit is also included in quartz. When the organopolysiloxane has a Q unit, using the composition containing this organopolysiloxane, a cured product with a refractive index value close to that of the core material of a near-infrared single-mode quartz fiber can be obtained.

[0160] In the organopolysiloxane represented by Formula [1], it may or may not have a Q unit. However, from the perspective of improving the heat resistance of the cured product of the organopolysiloxane, it is preferably provided with a Q unit, that is, Q>0. On the other hand, from the perspective of improving the flexibility of the cured product of the organopolysiloxane, it is preferably not provided with a Q unit, that is, Q = 0.

[0161] In the first embodiment of the present invention, when having a Q unit, the coefficient Q is preferably greater than 0, more preferably at least 0.04, still more preferably at least 0.10, and further preferably at least 0.30. On the other hand, when there are many Q units, it will become solid or the viscosity will increase, and the handling property will deteriorate. Therefore, the upper limit is usually 0.65 or less, more preferably 0.60 or less, and further preferably 0.45 or less.

[0162] As described above, when the organopolysiloxane represented by Formula [1] has a Q unit, its coefficient Q is preferably 0 < Q ≤ 0.65, more preferably 0.04 ≤ Q ≤ 0.60, and further preferably 0.04 ≤ Q ≤ 0.45.

[0163] <D1+D2+T1+T2+Q>

[0164] In the organopolysiloxane represented by Formula [1], when 0 < D1+D2+T1+T2+Q, it is possible to introduce structural units other than M units into the organopolysiloxane, which is advantageous from the viewpoints of curability and heat resistance after curing. Preferably 0.01 < D1+D2+T1+T2+Q, more preferably 0.1 < D1+D2+T1+T2+Q, and further preferably 0.2 < D1+D2+T1+T2+Q. The upper limit is not particularly limited, but is 1 or less according to the definition.

[0165] Furthermore, from the perspective of improving the heat resistance of the cured product of the organopolysiloxane, it is preferred that the relational expression “0 < D1+D2+T1+T2+Q” in Formula [1] is replaced by “0 < Q”, that is, having a Q unit. This will be described later using Formula [2].

[0166] <O 1 / 2 R 11 >

[0167] (O 1 / 2 R 11This unit is a structure that does not possess polymerizable functional groups and has groups selected from the group consisting of organic groups and hydrogen atoms, specifically alkoxy and / or silanol groups bonded to silicon. This structural unit allows control over the viscosity of organopolysiloxanes, enabling adjustment to a viscosity suitable for molding. Silanol groups increase viscosity, while alkoxy groups decrease it. If the proportion of alkoxy and silanol groups is low, the amount of highly mobile end groups is low, and the siloxane backbone becomes a rigid cage-like structure, thus increasing viscosity. Conversely, if the proportion of alkoxy or silanol groups is high, the amount of highly mobile end groups is high, and the siloxane backbone becomes a non-cage-like, flexible, random structure, thus decreasing viscosity.

[0168] <Coefficient Y1>

[0169] Indicates (O) 1 / 2 R 11 The proportional coefficient Y1 of ) is 0 or a positive value. In one scheme, according to R 11 By definition, Y1 represents the total proportion of silanol groups and alkoxy groups in the organopolysiloxane. From the viewpoint of viscosity adjustment necessary for the synthesis of organopolysiloxanes and the preparation of compositions containing organopolysiloxanes, as described later, the range of coefficient Y1 is preferably 0 or more, more preferably 0.02 or more, further preferably 0.025 or more, even more preferably 0.03 or more, and still more preferably 0.035 or more.

[0170] On the other hand, from the viewpoint of preserving stability and operability, the upper limit of the coefficient Y1 is preferably 0.25 or less, more preferably less than 0.25, further preferably 0.2 or less, even more preferably 0.20 or less, even more preferably 0.15 or less, and particularly preferably 0.1 or less.

[0171] As a preferred range, in formula [1], it is preferred that 0.02≤Y1≤0.25, more preferably 0.02≤Y1<0.25, even more preferably 0.025≤Y1≤0.2, even more preferably 0.025≤Y1≤0.20, even more preferably 0.03≤Y1≤0.15, and particularly preferably 0.035≤Y1≤0.1.

[0172] Y1 represents the relative value with respect to M1+M2+D1+D2+T1+T2+Q=1.

[0173] <Coefficient Y2>

[0174] Y2 represents the proportion of one or more organic groups in an organopolysiloxane that contain polymerizable functional groups bonded to silicon via oxygen atoms. (O) 1 / 2 R 6The coefficient Y2, representing the proportion of the compound, is 0 or a positive value, preferably Y2 > 0.25, more preferably Y2 > 0.30, and even more preferably Y2 > 0.35. If Y2 > 0.25, the compatibility with other resins is improved. Organic groups containing polymerizable functional groups are easily hydrolyzed and detached by water, thus sometimes resulting in high water absorption. Therefore, it is preferable to use the compound in a method less affected by moisture.

[0175] On the other hand, in environments affected by moisture, when Y2 is large, the solidified material is prone to becoming brittle due to moisture. Therefore, Y2 < 0.4 is preferred, Y2 < 0.3 is more preferred, and Y2 < 0.2 is even more preferred. In addition, Y2 of 0 is also preferred.

[0176] Y2 represents the relative value with respect to M1+M2+D1+D2+T1+T2+Q=1.

[0177] <Coefficient M1>

[0178] R without polymerizable functional groups 6 The M unit is not a necessary constituent element in organopolysiloxanes, but it can be included. Therefore, those without R 6 The proportion M1 of the M unit can be M1>0. By replacing either the alkoxy or silanol group of the organopolysiloxane with an M unit, it tends to improve the storage stability of the organopolysiloxane and reduce its viscosity. From the viewpoint of storage stability, the coefficient M1 is preferably 0.09 or higher, and is generally 0.6 or lower, preferably 0.5 or lower, and more preferably 0.4 or lower.

[0179] <Coefficient D1>

[0180] R without polymerizable functional groups 6 The D unit is not a necessary component in organopolysiloxanes, but by including this unit, it tends to impart toughness to the cured product. That is, from the viewpoint of imparting toughness to the cured product, D1 ≥ 0.2 is preferred, D1 ≥ 0.3 is more preferred, and D1 ≥ 0.4 is even more preferred.

[0181] On the other hand, if R is not present 6 If the content of D units is too high, the heat resistance of the cured product tends to decrease. That is, from the viewpoint of suppressing the decrease in the heat resistance of the cured product, D1 is preferably D1≤0.5, more preferably D1≤0.4, and even more preferably D1≤0.3.

[0182] <Coefficient T1>

[0183] R without polymerizable functional groups 6The T unit is not an essential component in the organopolysiloxane, but by including this unit, there is a tendency as follows: it can improve the compatibility with other components added to the composition containing the organopolysiloxane described later. From the viewpoint of improving the compatibility with other components, it is preferred that T1≥0.2, and more preferably T1≥0.3.

[0184] On the other hand, if the content of the T unit without R 6 is too high, due to the steric hindrance of the introduced organic groups, poor curing is likely to occur. Therefore, from the viewpoint of curability, it is preferred that T1≤0.5, more preferably T1≤0.4, and further preferably T1≤0.3.

[0185] As described above, each coefficient in the above formula [1] is preferably 0<Q≤0.65, 0<M2+D2+T2≤0.75, 0.02≤Y1≤0.25, Y2<0.4, 0<M1≤0.6, D1≤0.7, T1≤0.5, more preferably 0.04≤Q≤0.60, 0.10≤M2+D2+T2≤0.75, 0.025≤Y1≤0.20, Y2<0.3, 0.09≤M1≤0.5, D1≤0.6, T1≤0.4, and further preferably 0.04≤Q≤0.45, 0.12≤M2+D2+T2≤0.6, 0.03≤Y1≤0.15, Y2<0.2, 0.09≤M1≤0.4, D1≤0.3, T1≤0.3.

[0186] <R 6 >

[0187] R 6 is one or more organic groups containing a polymerizable functional group.

[0188] The polymerizable functional group of the organopolysiloxane is a reactive functional group that does not substantially react during the preparation of the organopolysiloxane and reacts by applying external energy, causing high molecular weightization through crosslinking or chain extension between organopolysiloxane molecules. As the external energy, light, heat, electron beam, etc. can be cited, and they can also be used in combination. When using light (active energy rays) as the external energy, it is preferred to perform exposure in a state where the organopolysiloxane coexists with a photoinitiator. In addition, in the exposure process, if only the desired part is selectively irradiated with active energy rays, only the exposed part can be made to have high molecular weightization, and the unexposed part can be dissolved in the developer and removed. As needed, after exposure and development, external energy such as active energy rays or heat can also be given to further perform high molecular weightization.

[0189] Specific examples of polymerizable functional groups include: vinyl, allyl, allyloxy, methacryloyl(oxy) group, acryloyl(oxy) group, ethyleneoxy group, trifluorovinyl, trifluoroethyleneoxy, ethynyl, 1-oxocyclopentan-2,5-dien-3-yl, cyano, alkoxysilyl, diarylhydroxymethyl, hydroxyfluorenyl, ethylene oxide, and epoxy. From the perspective of high reactivity and the attainment of high crosslinking density, vinyl, methacryloyl(oxy) group, acryloyl(oxy) group, trifluorovinyloxy group, ethynyl, and ethylene oxide and epoxy groups are preferred, more preferably methacryloyl(oxy) group or acryloyl(oxy) group, and most preferably methacryloyl(oxy) group. It should be noted that methacryloyl(oxy) group refers to methacryloyl or methacryloyloxy group. The same applies to acryloyl(oxy) group.

[0190] In these two schemes, specifically, R 6 It may contain a polymerizable alkenyl group as a polymerizable functional group. Examples of such a polymerizable alkenyl group include groups having acryloyl, methacryloyl, vinyl, styrene, etc. As R 6 The preferred group is an organic group in which at least one functional group selected from the group represented by the following formulas [i] to [iv] is contained in a molecule.

[0191] [Chemical Formula 1]

[0192]

[0193] (In the above formula, * represents a bond).

[0194] More preferably, R 6 A molecule has at least one functional group selected from the group consisting of acryloyloxypropyl, acryloyloxyoctyl, methacryloyloxypropyl, and methacryloyloxyoctyl, wherein, particularly preferably, a molecule has acryloyloxypropyl and / or methacryloyloxypropyl.

[0195] In formulas [ii] and [iv], X is a divalent organic group and optionally includes a branched structure and / or a cyclic structure. In addition to carbon and hydrogen, X optionally includes any one selected from the group consisting of oxygen, nitrogen, phosphorus, sulfur, and halogens. When a silicon atom is bonded to X, the atom that is terminal to X and directly bonded to silicon is preferably a carbon atom. When an oxygen atom directly bonded to silicon is bonded to X, the atom that is terminal to X and directly bonded to the oxygen atom is preferably a carbon atom. For example, hydrocarbon groups, polyalkylene glycols, etc., optionally containing 1 to 20 carbon atoms in a divalent branched or cyclic structure, may be appropriately used.

[0196] In the organopolysiloxane represented by formula [1], the units constituting the M unit, D unit, and T unit do not necessarily have to be all the same. For example, as a unit with a ratio of M1 (R 1 R 2 R 3 SiO 1 / 2 In, for example, it can also have a certain R. 1 For hydrogen atoms, a certain R 1 This is a different structure for methyl groups. This is also common to other R and X groups.

[0197] <R 1 ~R 5 R 7 ~R 11 >

[0198] R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0199] In R 1 ~R 5 R 7 ~R 11 When the group is an organic group, it is preferably an organic group with 1 to 20 carbon atoms. Specifically, it is preferably a straight-chain, branched, or cyclic alkyl group with 1 to 20 carbon atoms, or an aromatic cyclic group with 6 to 20 carbon atoms. More specifically, it is preferably an alkyl group such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, octyl, or cyclohexyl, or a polyether group such as a polyalkylene glycol group, and is particularly preferably methyl.

[0200] The organopolysiloxane having polymerizable alkenyl groups is also preferably represented by the following formula [2].

[0201] (R) 1 R 2 R 3 SiO 1 / 2 ) M1 (R) 4 R 5 R 6 SiO 1 / 2 ) M2

[0202] (R) 7 R 8 SiO 2 / 2 ) D1 (R) 9 R 6 SiO 2 / 2 ) D2

[0203] (R 10 SiO 3 / 2 ) T1 (R 6 SiO 3 / 2 ) T2 (SiO 4 / 2 ) Q

[0204] (O 1 / 2 R 11 ) Y1 (O 1 / 2 R 6 ) Y2 ……[2]

[0205] In general formula [2], the coefficients M1, M2, D1, D2, T1, T2, and Q represent the proportions of the respective structures (based on the number of moles) when M1 + M2 + D1 + D2 + T1 + T2 + Q = 1. In addition, in general formula [2], the coefficients Y1 and Y2 represent the relative content ratios of (O 1 / 2 R 11 ) and (O 1 / 2 R 6 ) (based on the number of moles).

[0206] The organopolysiloxane having a polymerizable alkenyl group represented by formula [2] is an organopolysiloxane with 0 < Q. That is, it is characterized by having a Q unit. By having a Q unit, the heat resistance of the cured product of the organopolysiloxane can be improved.

[0207] Except for removing Q = 0, the allowable ranges of the coefficients M1, M2, D1, D2, T1, T2, and Q also include preferred combinations, as described in the above formula [1]. Regarding the structural units represented by each coefficient, they are also as described in the above formula [1].

[0208] The organopolysiloxane having a polymerizable functional group is also preferably represented by the following formula [3].

[0209] (R 1 R[[ID=5�]] 2 R 3 SiO 1 / 2 ) M1 (R 4 R 5 R 6 SiO 1 / 2 ) M2

[0210] (R 7 R 8 SiO 2 / 2 ) D1 (R9 R 6 SiO 2 / 2 ) D2

[0211] (R) 10 SiO 3 / 2 ) T1 (R) 6 SiO 3 / 2 ) T2

[0212] (O) 1 / 2 R 11 ) Y1 (O) 1 / 2 R 6 ) Y2 ...[3]

[0213] In the above formula [3], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms.

[0214] R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymerizable functional groups.

[0215] R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other.

[0216] 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2,

[0217] 0 <M2+D2+T2、

[0218] 0 <D1+D2+T1+T2、

[0219] M1+M2+D1+D2+T1+T2=1.

[0220] Equation [3] represents an organopolysiloxane in Equation [1] with coefficient Q being 0, i.e., without Q units.

[0221] R in equation [3] 1 ~R 11 As with formula [1], the preferred groups are also the same.

[0222] M1, M2, D1, D2, T1, T2, Y1, and Y2 are the same as in equation [1], and the preferred numerical ranges of each coefficient are also the same.

[0223] <D1 + D2 + T1 + T2>

[0224] In the organopolysiloxane represented by Formula [3], when 0 < D1 + D2 + T1 + T2, structural units other than M units can be introduced into the organopolysiloxane, which is advantageous from the viewpoints of curability and heat resistance after curing. Preferably, 0.01 < D1 + D2 + T1 + T2, more preferably 0.1 < D1 + D2 + T1 + T2, and still more preferably 0.2 < D1 + D2 + T1 + T2. There is no particular limitation on the upper limit, and it is 1 or less according to the definition.

[0225] From the viewpoint of introducing a soft part into the organopolysiloxane and improving the crack resistance of its cured product, 0 < D1 + D2 is preferred. More preferably, D1 + D2 ≥ 0.05, still more preferably D1 + D2 ≥ 0.1, and even more preferably D1 + D2 > 0.1. In addition, from the viewpoint of suppressing the thermal expansion of the cured product of the organopolysiloxane, D1 + D2 ≤ 0.9 is preferred, and more preferably D1 + D2 ≤ 0.8.

[0226] Regarding one of the D unit structures that does not have a polymerizable vinyl group and does not become a crosslinking point, its effect of imparting toughness is high. Therefore, within the range of the value of D1 + D2 described above, D2 = 0 is also possible. From the same viewpoint, 0 < D1 is also preferred, more preferably 0.1 < D1, still more preferably 0.20 ≤ D1, even more preferably 0.25 ≤ D1, and particularly preferably 0.30 ≤ D1. There is no particular limitation on the upper limit of D1, and preferably D1 ≤ 0.80, more preferably D1 ≤ 0.75, and still more preferably D1 ≤ 0.70.

[0227] By adjusting the values of D1 and D2 to the above ranges, the roughness of the end face during cutting of the optical waveguide made of this organopolysiloxane is suppressed, and light scattering is also suppressed, and there is a tendency for the connection loss to become smaller.

[0228] From the viewpoint of improving the heat resistance of the cured product of the organopolysiloxane, 0 < T1 + T2 is preferred. More preferably, T1 + T2 ≥ 0.05, and still more preferably T1 + T2 ≥ 0.1. From the viewpoint of suppressing the curing shrinkage of the cured product of the organopolysiloxane, T1 + T2 ≤ 0.9 is preferred, and more preferably T1 + T2 ≤ 0.8. <​​​As described above, in the above formula [3], each ratio is preferably 0 < M2 + D2 + T2 ≤ 0.9, 0.02 ≤ Y1 ≤ 0.25, Y2 < 0.4, 0 < M1 ≤ 0.6, D1 ≤ 0.5, T1 ≤ 0.5, more preferably 0.10 ≤ M2 + D2 + T2 ≤ 0.8, 0.025 ≤ Y1 ≤ 0.20, Y2 < 0.3, 0.09 ≤ M1 ≤ 0.5, D1 ≤ 0.4, T1 ≤ 0.4, and further preferably 0.12 ≤ M2 + D2 + T2 ≤ 0.6, 0.03 ≤ Y1 ≤ 0.15, Y2 < 0.2, 0.09 ≤ M1 ≤ 0.4, D1 ≤ 0.3, T1 ≤ 0.3.

[0231] The core and cladding portions of the optical waveguide of the present invention can be obtained by curing the above-described composition containing an organopolysiloxane having a polymerizable functional group. In addition, in order to suppress an increase in the refractive index of the cured product, it is also preferable to use an organopolysiloxane having no aromatic structure as the organopolysiloxane having a polymerizable functional group. The content of the aromatic group can be determined by 1 H-NMR, 29 Si-NMR. "Having no" aromatic structure means that in the NMR spectrum, there is no distinct peak that can be clearly identified as an aromatic group.

[0232] [Manufacturing Method of Organopolysiloxane Having Polymerizable Functional Group]

[0233] The manufacturing method of the organopolysiloxane having a polymerizable functional group is not particularly limited as long as the organopolysiloxane represented by the above formula [1], formula [2], and formula [3] can be obtained. <000086%>For example, a method of simultaneously condensing one or more disiloxane compounds, disilazane compounds, and their hydrolyzates, alkoxysilane compounds, their hydrolyzates, and partial hydrolysis condensates; a method of condensing chlorosilane compounds, their hydrolyzates, and partial hydrolysis condensates; a method of ring-opening polymerization of cyclic siloxane compounds; any manufacturing method such as chain polymerization represented by anionic polymerization, etc. can be used, and multiple manufacturing methods can also be used in combination.

[0235] In addition, the method for introducing the polymerizable functional group is not particularly limited, and a method of simultaneously condensing one or more alkoxysilane compounds, disiloxane compounds, disilazane compounds having a polymerizable functional group, or their hydrolyzates and partial hydrolysis condensates; a method of converting a reactive organic group introduced into the organopolysiloxane into a polymerizable functional group by a chemical method, etc. can be used, and these methods can also be used in combination.

[0236] Hereinafter, raw materials for manufacturing an organopolysiloxane having a polymerizable functional group by hydrolysis condensation are exemplified as follows.

[0237] (M-unit source)

[0238] As an example of an M-unit source, trimethylsilanol, trimethylmethoxysilane, hexamethyldisiloxane, hexamethyldisilazane, dimethylsilanol, dimethylmethoxysilane, tetramethyldisiloxane, tetramethyldisilazane, dimethylvinylsilanol, dimethylvinylmethoxysilane, 1,3-divinyltetramethyldisiloxane, 1,3-divinyltetramethyldisilazane, dimethyl(meth)acryloyloxypropylsilanol, dimethyl(meth)acryloyloxypropylmethoxysilane, 1,3-di(meth)acryloyloxypropyltetramethyldisiloxane, dimethylglycidoxypropylmethoxysilane, 1,3-bis(3-glycidoxypropyl)tetramethyldisiloxane, 3-(meth)acryloyloxypropyldimethylsilanol, 3-(meth)acryloyloxypropyldimethylmethoxysilane, 1,3 -Bis((meth)acryloyloxypropyl)-1,1,3,3-tetramethyldisiloxane, tetramethyldisiloxane, methoxytriphenylsilane, triphenylsilanol, 1,3-diphenyltetramethyldisiloxane, 1,3-diphenyltetramethyldisilazane, dimethylphenylsilanol, dimethylmethoxyphenylsilane, 1,4-bis(dimethylmethoxysilyl)benzene, 1,4-bis(dimethylethoxysilyl)benzene, 2-(3,4-epoxycyclohexyl)ethyldimethylmethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldimethylethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyldimethylethoxysilane, and compounds containing silanol hydroxyl or alkoxy groups among the above-listed compounds, and compounds in which halogens are bonded to replace the silanol hydroxyl or alkoxy groups. As an M-unit source, hexamethyldisiloxane is particularly preferred.

[0239] (D-cell source)

[0240] As an example of a D-unit source, dimethyldisilanediol, dimethyldimethoxysilane, diphenyldisilanediol, diphenyldimethoxysilane, tetramethyldisiloxane, 3-(meth)acryloyloxypropyldimethoxymethylsilane, methyldimethoxyphenylsilane, diethoxymethylphenylsilane, methylphenyldisilanediol, 1,4-bis(methyldimethoxysilyl)benzene, 1,4-bis(methyldiethoxysilyl)benzene, dimethoxy(methyl) (3 The group of compounds including 3,3-trifluoropropyl)silane, 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and compounds in which halogenated elements are bonded to replace the silanol hydroxyl or alkoxy groups, and polymers thereof, especially dimethyldimethoxysilane may be preferred.

[0241] (T-unit source)

[0242] Examples of T-unit sources include: trimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, etc., which are oxidized by C1-C2. 20 Long-chain alkoxy-modified trimethoxysilanes, vinyltrimethoxysilanes, phenyltrimethoxysilanes, 3,3,3-trifluoropropyltrimethoxysilanes, 3-(meth)acryloyloxypropyltrimethoxysilanes, 8-(meth)acryloyloxyoctyltrimethoxysilanes, 1,4-bis(trimethoxysilyl)benzene, p-styryltrimethoxysilanes, 3-glycidoxypropyltrimethoxysilanes, 8-glycidoxyoctyltrimethoxysilanes, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilanes, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilanes, 3-glycidoxypropyltriethoxysilanes, and 3-glycidoxypropyltrimethoxysilanes are also permitted. In addition to these methoxysilane compounds, alkoxysilanes such as ethoxysilanes, silanols, chlorosilanes, hydrosilylsilanes, and their polymers may also be used. In particular, 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 8-acryloxyoctyltrimethoxysilane, and decyltrimethoxysilane are preferred.

[0243] (Q-cell source)

[0244] As an example of a Q-unit source, tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrapentoxysilane, tetraphenoxysilane, trimethoxymonoethoxysilane, dimethoxydiethoxysilane, triethoxymonomethoxysilane, trimethoxymonopropoxysilane, monomethoxytributoxysilane, monomethoxytripentoxysilane, monomethoxytriphenoxysilane, dimethoxydipropoxysilane, tripropoxymonomethoxysilane, trimethoxymonobutoxysilane, dimethoxymonopropoxysilane, triethoxymonopropoxysilane, diethoxymonopropoxysilane, tributoxymonopropoxysilane, dimethoxymonoethoxymonobutoxysilane alkoxysilanes or aryloxysilanes, such as diethoxymonomethoxymonobutoxysilane, diethoxymonopropoxymonobutoxysilane, diethoxymonomethoxymonoethoxysilane, diethoxymonoethoxymonobutoxysilane, diethoxymonomethoxymonoethoxysilane, diethoxymonoethoxymonopropoxysilane, and monomethoxymonoethoxymonopropoxymonobutoxysilane; methyl silicate MS51, MS56, MS57, and MS60 manufactured by Mitsubishi Chemical Corporation as tetramethoxysilane oligomers; and ethyl silicate oligomers ES40 and ES48 manufactured by Tama Chemical Industry Co., Ltd. as tetraethoxysilane oligomers, with methyl silicate MS51 being particularly preferred.

[0245] The above-mentioned M, D, T, and Q unit sources can be used in combination of one or more.

[0246] As a catalyst for the hydrolysis and condensation of these silicon raw materials, an acid catalyst, a base catalyst, or an inorganic salt can be used, with an acid catalyst being particularly preferred.

[0247] As an example of an acid catalyst, hydrochloric acid, sulfuric acid, trifluoroacetic acid, acetic acid, methacrylic acid, acrylic acid, etc. can be used, with hydrochloric acid being particularly preferred.

[0248] As an example of an alkaline catalyst, ammonia, hexamethyldisilazane, triethylamine, tetraethylammonium hydroxide, diazabicycloundecene, potassium hydroxide, sodium hydroxide, barium hydroxide, potassium carbonate, sodium carbonate, etc., can be used, with potassium hydroxide being particularly preferred.

[0249] As an inorganic salt, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, etc. can be used, with sodium chloride being particularly preferred.

[0250] As an example of a solvent used in a hydrolysis-condensation reaction, tetrahydrofuran, toluene, methanol, ethanol, isopropanol, hexane, heptane, etc. can be used, with tetrahydrofuran being particularly preferred. Two or more solvents can also be used depending on the solubility of the product, with a mixture of toluene and methanol or a mixture of tetrahydrofuran and methanol being particularly preferred.

[0251] For any alkoxy or silanol groups remaining after unhydrolyzed condensation, they can be substituted with organic acids or alcohols as needed. Examples of organic acids include acetic acid, acrylic acid, and methacrylic acid. Examples of alcohols include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, and their structural isomers, which are alcohols without polymerizable alkenyl groups. Alcohols containing polymerizable alkenyl groups include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate; from a stability point of view, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are preferred.

[0252] When the organopolysiloxane has a rigid structure like a fully cage-like silsesquioxane, the cured product becomes hard and brittle; therefore, a non-fully cage-like structure is preferred. As long as it is not a fully cage-like silsesquioxane, for example, a random structure or a trapezoidal structure as an advanced structure can be included without impairing the effects of the present invention.

[0253] <Water>

[0254] The amount of water used for hydrolysis is preferably 0.5 equivalents or more, more preferably 0.8 equivalents or more, and even more preferably 1.1 equivalents or more, relative to the total amount of alkoxy groups contained in the MDTQ unit source. The water is not particularly limited and can be water contained in commercially available hydrochloric acid, or water purified by distillation or ion exchange resin.

[0255] As described above, in both embodiments, at least one of the core and the cladding portion needs to be made of a cured product formed by curing a composition containing the organopolysiloxane shown in the above formula [1]. However, the core and the cladding portion may also be made of other materials as long as the effect of the present invention is not impaired.

[0256] For example, various resin materials can be used, such as acrylic resins (represented by organic-inorganic hybrid materials with polymerizable functional groups like organopolysiloxanes), methacrylic resins like polymethyl methacrylate (PMMA), epoxy resins, oxetane resins, phenoxy resins, benzocyclobutene resins, norbornene resins, fluorinated resins, organosilicon resins, phenolic resins, polyester resins, polycarbonate resins, polystyrene resins, polyamide resins, polyimide resins, poly(imide-isoindoloquinazoline diketone imide) resins, polyetherimide resins, polyetherketone resins, polyesterimide resins, polybenzoxazole resins, and polysilanes. Among these materials, those with high transparency and high heat resistance in the near-infrared band are preferred for use as core or cladding materials.

[0257] However, in both of these schemes, it is preferred that the core and the cladding are both composed of a cured product formed by curing a composition containing an organopolysiloxane represented by formula [1].

[0258] [A composition containing an organopolysiloxane having polymerizable functional groups]

[0259] The composition of the present invention containing an organopolysiloxane having polymerizable functional groups (hereinafter, sometimes simply referred to as "a composition containing an organopolysiloxane") is used to form an optical waveguide. As described above, this composition is preferably a composition containing an organopolysiloxane having polymerizable functional groups, and more preferably a composition containing an organopolysiloxane having polymerizable alkenyl groups. In addition to the organopolysiloxanes described above, this composition may also contain monofunctional polymerizable alkenyl compounds, polyfunctional polymerizable alkenyl compounds, and / or alkenyl polymers, etc., without impairing the properties of the cured product obtained from this composition as described later.

[0260] Furthermore, in order to polymerize and cure organopolysiloxanes and polymerizable alkenyl compounds, a polymerization initiator may be included. It is also possible to cure organopolysiloxanes or compositions containing organopolysiloxanes by means of electron beam irradiation without using a polymerization initiator; however, since curing requires a large amount of energy, the preferred embodiment of the composition containing organopolysiloxanes in this invention is that, in addition to the organopolysiloxanes described above, it contains at least a polymerization initiator.

[0261] In addition, as other components, the composition may contain sensitizers, chain transfer agents, antioxidants, ultraviolet absorbers, light stabilizers, leveling agents, rheology modifiers, silane coupling agents and other adhesive aids, dyes, defoamers, other components, solvents, etc., to a extent that does not impair the properties of the cured product obtained from the composition.

[0262] The following describes the components optionally included in compositions containing organopolysiloxanes.

[0263] <Monofunctional polymeric alkenyl compounds>

[0264] Specific examples of monofunctional polymeric alkenyl compounds include carboxyl esters such as (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, and 2-(meth)acryloyloxyethyl hexahydrophthalate.

[0265] 2-Hydroxyethyl methacrylate, 2-Hydroxypropyl methacrylate, 2-Hydroxybutyl methacrylate, 4-Hydroxybutyl methacrylate, 6-Hydroxyhexyl methacrylate and other hydroxyl-containing methacrylates;

[0266] Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, and other alkyl methacrylates.

[0267] Cyclohexyl methacrylate, dicyclopentenyl methacrylate, 2-dicyclopentenoxyethyl methacrylate, isobornyl methacrylate, dicyclopentenyl methacrylate, adamantane methacrylate, 4-tert-butylcyclohexyl methacrylate, and other methacrylates containing alicyclic structures;

[0268] (Meth)acrylates containing aromatic ring structures include phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, diethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, phenyl methacrylate, phenyl phenoxyethyl methacrylate, phenoxybenzyl methacrylate, phenyl benzyl methacrylate, naphthyl methacrylate, and (1-naphthyl)methyl methacrylate.

[0269] Tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, methacryloylmorpholine, and other (meth)acrylates containing heterocyclic structures;

[0270] (Meth)acrylate methoxyethyl ester, (meth)acrylate ethoxyethyl ester, (meth)acrylate butoxyethyl ester, and other (meth)acrylate alkoxy esters;

[0271] 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 2-(meth)acryloyloxyethyl acid phosphate, trifluoroethyl (meth)acrylate and heptadecafluorodecyl (meth)acrylate, 2-(meth)acryloyloxyethyl isocyanate;

[0272] Styrene, α-methylstyrene, 2-vinylpyridine, 4-vinylpyridine, 1,1-diphenylethylene and their aromatic cyclic hydrogen-substituted derivatives, and other styrene derivatives;

[0273] Vinyl compounds such as vinyl acetate, vinyl octanoate, vinyl decanoate, vinyl hexanoate, acrylonitrile, and vinyl benzoate.

[0274] It should be noted that since the refractive index of the cured material will increase, it is preferable to use a substance that does not contain aromatic structures.

[0275] <Multifunctional polymeric alkenyl compounds>

[0276] Specific examples of multifunctional polymerizable alkenyl compounds include: ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and other alkylene glycol di(meth)acrylates;

[0277] Polyalkylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, and other polyalkylene glycol di(meth)acrylates;

[0278] Cyclohexanediethanol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, ethoxylated hydrogenated bisphenol A di(meth)acrylate, propoxylated hydrogenated bisphenol A di(meth)acrylate, adamantanediol di(meth)acrylate, and other di(meth)acrylates containing alicyclic structures;

[0279] Difunctional (meth)acrylates such as polycarbonate diol di(meth)acrylate, polyester diol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, 9,9-bis(4-acryloyloxyethoxyphenyl)fluorene, and polyurethane di(meth)acrylate.

[0280] Trifunctional (meth)acrylates include trimethylolpropane tri(meth)acrylate, ethoxylated isocyanurate tri(meth)acrylate, and ε-caprolactone-modified tri((meth)acryloyloxyethyl)isocyanurate.

[0281] Tetrafunctional (meth)acrylates such as bis(trimethylolpropane)tetra(meth)acrylate;

[0282] Pentafunctional (meth)acrylates such as dipentaerythritol penta(meth)acrylate;

[0283] Dipentaerythritol hexa(meth)acrylate and other hexafunctional (meth)acrylates and other multifunctional monomers;

[0284] 1,4-Divinylbenzene, 1,3-Divinylbenzene, etc.

[0285] It should be noted that since the refractive index of the cured material will increase, it is preferable to use a substance that does not contain aromatic structures.

[0286] <Alkenyl Polymers>

[0287] Alkenyl polymers are polymers whose composition contains 50% by mass or more of alkenyl monomer units. In this specification, "unit" refers to a repeating unit constituting the polymer. Alkenyl polymers can be monofunctional or polyfunctional. Furthermore, since the refractive index of the cured product increases and it becomes more brittle, it is preferable to use substances that do not contain aromatic structures.

[0288] Alkenyl polymers can contain one or more alkenyl monomer units.

[0289] The polymerization method used to obtain the alkenyl polymer is not particularly limited. For example, polymerization can be carried out by known methods such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization. In this invention, suspension polymerization is preferred from the perspective of controlling the polymerization reaction and the relative ease of separating the resulting polymer.

[0290] As an alkenyl polymer, it is possible to use substances modified by introducing functional groups containing double bonds, such as (meth)acryloyl or vinyl groups, into the side chains through chemical modification. Examples of chemical modification methods include the reaction of carboxyl groups with glycidyl groups and the reaction of hydroxyl groups with isocyanate groups.

[0291] When using the reaction of carboxyl and glycidyl groups as a chemical modification method, for example, a method can be described to manufacture an alkenyl polymer containing an alkenyl monomer unit having a carboxyl group, and then react the resulting alkenyl polymer with a compound having a glycidyl group and a double bond, such as glycidyl (meth)acrylate.

[0292] To shorten the reaction time, a reaction catalyst is preferably used for the reaction of alkenyl polymers containing carboxyl monomer units with compounds containing glycidyl groups and double bonds. Examples of reaction catalysts include quaternary ammonium salts such as tetrabutylammonium bromide, quaternary phosphonium salts such as ethyltriphenylphosphonium bromide, and phosphine compounds such as triphenylphosphine. From the viewpoint that the composition containing organopolysiloxanes in this embodiment is less prone to coloring, quaternary ammonium salts are particularly preferred.

[0293] The weight-average molecular weight (Mw) of the alkenyl polymer is preferably 5,000 to 500,000, more preferably 10,000 to 200,000. If the weight-average molecular weight is 5,000 or more, the strength of the cured product becomes good. If it is 500,000 or less, the viscosity of the composition containing organopolysiloxane in this embodiment decreases, and therefore the workability becomes good.

[0294] <Polymerization initiator>

[0295] Examples of polymerization initiators include photopolymerization initiators, thermal polymerization initiators, and peroxides used in redox polymerization. The type of polymerization initiator can be appropriately selected based on the polymerization method.

[0296] (Photopolymerization initiator)

[0297] Photopolymerization initiators are free radical polymerization initiators used in photopolymerization. Specific examples of photopolymerization initiators include: benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, methyl 2-benzoylbenzoate, 4-phenylbenzophenone, and other benzophenone-type compounds; anthraquinone-type compounds such as tert-butylanthraquinone and 2-ethylanthraquinone; 2-hydroxy-2-methyl-1-phenylpropane-1-one, oligomeric {2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone}, benzyl dimethyl... Alkyl ketal compounds such as 1-hydroxycyclohexylphenyl ketone, benzoin methyl ether, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropanoyl)benzyl]phenyl}-2-methylpropane-1-one; thioxanthone compounds such as 2-benzyl-2-dimethylamino-4'-morpholinobutyrophenyl, diethylthioxanthone, and isopropylthioxanthone; 2,4,6-trimethylbenzyl... Acylphosphine oxides, such as bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; phenylglyoxal esters, such as methyl phenylglyoxalate; N-acetoxy-N-{4-acetoxyimino-4-[9-ethyl-6-(o-tolyl)-9H-carbazole-3-yl]but-2-yl}acetamide, N-acetyl... Oxime esters such as oxy-N-{3-(acetoxyimino)-3-[9-ethyl-6-(1-naphthoyl)-9H-carbazole-3-yl]-1-methylpropyl}acetamide, methyl 4-acetoxyimino-5-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-5-oxovalerate, and methyl 4-acetoxyimino-5-oxo-5-(4-(phenylthio)phenyl)valerate; and combinations thereof.

[0298] Among these, alkyl phenyl ketone type compounds are preferred for suppressing coloration of the cured product, and 2-hydroxy-2-methyl-1-phenylpropane-1-one and 1-hydroxycyclohexylphenyl ketone are more preferred. Furthermore, acylphosphine oxide type compounds are preferred for facilitating thorough curing of the cured product to its interior, and 2,4,6-trimethylbenzoyl diphenylphosphine oxide and methyl 4-acetoxyimino-5-oxo-5-(4-(phenylthio)phenyl)valerate are more preferred for suppressing coloration of the cured product. More preferably, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide has high photosensitivity to longer wavelengths of light. From the viewpoint of high reactivity to light near 365 nm, 2-benzyl-2-dimethylamino-4'-morpholinylbutyrophenyl is preferred. These photopolymerization initiators can be used alone or in combination of two or more.

[0299] When a cured product is obtained by photopolymerization of the composition containing organopolysiloxane, the wavelength of the light irradiating the composition containing organopolysiloxane is not particularly limited, but ultraviolet light with a wavelength of 200 to 500 nm is preferred. Specific examples of ultraviolet light sources include ultra-high pressure mercury lamps, high pressure mercury lamps, metal halide lamps, high-power metal halide lamps, UV-LED lamps, chemical lamps, and black light lamps.

[0300] After photopolymerizing a composition containing organopolysiloxanes, post-curing can be performed. Post-curing reduces the amount of unreacted polymeric alkenes remaining in the cured product, further improving its strength. Examples of post-curing conditions include temperatures of 50°C to 200°C for tens of seconds to 60 minutes, or temperatures of 80°C to 150°C for tens of seconds to 60 minutes.

[0301] (Thermal polymerization initiator)

[0302] Thermal polymerization initiators are free radical polymerization initiators used for thermal polymerization. Examples of thermal polymerization initiators include organic peroxides and azo compounds.

[0303] Specific examples of organic peroxides include: ketone peroxides such as methyl ethyl ketone peroxide; ketal peroxides such as 1,1-di(tert-hexylperoxide)-3,3,5-trimethylcyclohexane, 1,1-di(tert-hexylperoxide)cyclohexane, and 1,1-di(tert-butylperoxide)cyclohexane; hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and p-menthane hydroperoxide; and diisopropylphenyl peroxide. Dialkyl peroxides such as di-tert-butyl peroxide; dilauroyl peroxide, dibenzoyl peroxide, and other dialkyl peroxides; dicarbonates such as di(4-tert-butylcyclohexyl) peroxide and di(2-ethylhexyl) peroxide; and peroxide esters such as tert-butyl peroxide-2-ethylhexanoate, tert-hexyl peroxide-isopropyl monocarbonate, tert-butyl peroxide-benzoate, and 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate.

[0304] Specific examples of azo compounds include: 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylpentanitrile), 1,1'-azobis-1-cyclohexanecarboxylonitrile, dimethyl 2,2'-azobisisobutyrate, 4,4'-azobis-4-cyanopentanoic acid, and 2,2'-azobis-(2-amidinylpropane) dihydrochloride, etc.

[0305] These thermal polymerization initiators can be used alone or in combination of two or more. Organic peroxides are preferred as thermal polymerization initiators because they minimize the formation of bubbles in the cured product. Considering the balance between the curing time and pot life of the composition containing organopolysiloxanes, the 10-hour half-life temperature of the organic peroxide is preferably 35–80°C, more preferably 40–75°C, and even more preferably 45–70°C. If the 10-hour half-life temperature is 35°C or higher, the composition containing organopolysiloxanes is less prone to gelation at room temperature, resulting in a good pot life. On the other hand, if the 10-hour half-life temperature is below 80°C, the curing time of the composition containing organopolysiloxanes can be shortened.

[0306] Examples of such organic peroxides include 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, and di(4-tert-butylcyclohexyl) peroxide dicarbonate. Commercially available products of 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate include PEROCTA O (trade name, manufactured by Nippon Oil Co., Ltd., 10-hour half-life temperature: 65.3°C). Commercially available products of tert-butyl peroxide-2-ethylhexanoate include PERBUTYL O (trade name, manufactured by Nippon Oil Co., Ltd., 10-hour half-life temperature: 72.1°C). Commercially available products of di(4-tert-butylcyclohexyl) peroxide dicarbonate include PEROYL TCP (trade name, manufactured by Nippon Oil Co., Ltd., 10-hour half-life temperature: 40.8°C).

[0307] When a cured product is obtained by curing a composition containing organopolysiloxane through thermal polymerization, the curing conditions are not particularly limited. From the viewpoint of easily obtaining a resin for optical components with suppressed coloration, the curing temperature is preferably 40 to 200°C, more preferably 60 to 150°C. The curing time (heating time) varies depending on the curing temperature, preferably 1 to 120 minutes, more preferably 1 to 60 minutes.

[0308] Preferably, after thermally polymerizing the composition containing organopolysiloxane, post-curing is further performed. Examples of post-curing conditions include tens of seconds to 60 minutes at a temperature of 50°C to 200°C, or tens of seconds to 60 minutes at a temperature of 80°C to 150°C.

[0309] (Redox polymerization)

[0310] Redox polymerization typically uses redox-based polymerization initiators. Redox-based polymerization initiators are polymerization initiators that combine a peroxide with a reducing agent. Examples of peroxides used in redox polymerization include benzoyl peroxide and hydrogen peroxide. These peroxides can be used alone or in combination with two or more. An example of a combination of the above-mentioned peroxides as redox polymerization initiators with a reducing agent is described below.

[0311] (1) Combination of benzoyl peroxide (peroxide) with aromatic tertiary amines (reducing agents) such as N,N-dimethylaniline, N,N-dimethyl-p-toluidine, and N,N-bis(2-hydroxypropyl)-p-toluidine.

[0312] (2) Combination of hydroperoxide (peroxide) and metal soap (reducing agent).

[0313] (3) Combination of hydroperoxide (peroxide) and thiourea (reducing agent).

[0314] When a cured product is obtained by curing a composition containing an organopolysiloxane through redox polymerization, curing can be carried out at room temperature of 5–40°C by using a redox polymerization initiator. From the perspective of reducing the amount of unreacted (meth)acryloyl groups remaining in the obtained cured product and further improving the strength of the cured product, the curing temperature is preferably 15–40°C.

[0315] From the viewpoint that the composition containing organopolysiloxane is not prone to gelation and can be handled stably, it is preferable to carry out the curing method in the following order: dissolve the reducing agent in the composition containing organopolysiloxane in advance, and add peroxide thereto.

[0316] When curing a composition containing organopolysiloxanes, it is preferable to cure the composition in a sealed state to suppress curing obstacles caused by oxygen. Examples of sealing methods include embedding the composition containing organopolysiloxanes within glass or PET films.

[0317] <Chain transfer agent>

[0318] In the case of curing a composition containing organopolysiloxane in air, active free radicals are captured as peroxide free radicals due to oxygen, and polymerization is hindered. However, by adding a chain transfer agent that imparts hydrogen, the polymerization hindrance caused by oxygen can be suppressed.

[0319] Examples of chain transfer agents, such as thiols, include: methyl mercaptoacetate, methyl 3-mercaptopropionate, 2-ethylhexyl 3-mercaptopropionate, 3-methoxybutyl 3-mercaptopropionate, n-octyl 3-mercaptopropionate, stearyl 3-mercaptopropionate, 1,4-bis(3-mercaptopropionyloxy)butane, 1,4-bis(3-mercaptobutyryloxy)butane, trimethylolethane tris(3-mercaptopropionate), trimethylolethane tris(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetras(3-mercaptopropionate), pentaerythritol tetras(3-mercaptobutyrate), dipentaerythritol hexa(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptobutyrate), tri[2-(3-mercaptopropionyloxy) [Acyloxy]ethyl]isocyanurate, tris[2-(3-mercaptobutyryloxy)ethyl]isocyanurate and other mercaptocarboxylic acid esters; ethanethiol, 2-methylpropane-2-thiol, n-dodecanethiol, 2,3,3,4,4,5-hexamethylhexane-2-thiol (tert-dodecanethiol), ethane-1,2-dithiol, propane-1,3-dithiol, benzylthiol and other alkylthiols; thiophenol, 3-methylthiophenol, 4-methylthiophenol, naphthiophenol, pyridine-2-thiophenol, benzimidazole-2-thiophenol, benzothiazole-2-thiophenol and other aromatic thiophenols; 2-mercaptoethanol, 4-mercapto-1-butanol and other mercaptools; 3-(trimethoxysilyl)propane-1-thiol, 3-(triethoxysilyl)propane-1-thiol and other silane-containing thiols, etc. From the viewpoint of the reactivity and storage stability of the curable composition, secondary thiol compounds are preferred.

[0320] When a chain transfer agent is added, it can be used alone or in combination with two or more other chain transfer agents. Furthermore, the amount added is 0.01 to 20 parts by mass relative to 100 parts by mass of the total polymerizable component, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 10 parts by mass. It should be noted that when two or more chain transfer agents are used in combination, the total amount of chain transfer agent is within the above range.

[0321] Solvent

[0322] For the purpose of diluting compositions containing organopolysiloxanes, they may contain solvents.

[0323] The type of solvent is not particularly limited as long as it does not impair the required physical properties of the cured product containing the organopolysiloxane. Aromatic hydrocarbons with good solubility (e.g., toluene, xylene, ethyl benzoate, ethylbenzene, benzyl alcohol), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, diacetone alcohol), and esters (e.g., methyl acetate, ethyl acetate, butyl acetate, sec-butyl acetate, methoxybutyl acetate, amyl acetate, n-propyl acetate, ethyl lactate, methyl lactate, butyl lactate) can be used. Solvents such as propylene glycol monomethyl ether acetate, γ-butyrolactone, ethers (e.g., isopropyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monobutyl ether, 1,4-dioxane, methyl tert-butyl ether, tetrahydrofuran), alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, butanol, sec-butanol, tert-butanol, n-pentanol), halogen solvents (e.g., dichloromethane, trichloroethylene, tetrachloroethylene, bromopropane, chloroform), and others (e.g., dimethyl sulfoxide, N,N-dimethylformamide, water) may also be used, and two or more solvents may also be used.

[0324] The content of the solvent in the composition containing organopolysiloxane is not particularly limited as long as it does not impair the required physical properties of the cured product of the composition containing organopolysiloxane. However, if it is desirable to suppress volatile matter to a small amount and reduce viscosity, it is preferably greater than 0% by mass and less than 25% by mass relative to the total composition containing organopolysiloxane. Furthermore, in the case of obtaining a cured film, it is preferably 75% by mass or more and less than 100% by mass relative to the total composition.

[0325] (Antioxidants)

[0326] Preferably, the composition containing organopolysiloxane further contains an antioxidant. By including an antioxidant in the composition containing organopolysiloxane, coloring caused by heat such as heating during soldering of the cured product or heat generated by the device can be suppressed.

[0327] Specific examples of antioxidants include: 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], and 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], etc., which are phenolic antioxidants. Antioxidants include: phosphorus-based antioxidants such as triphenyl phosphite, triisodecyl phosphite, tri(tetrazyl) phosphite, tri(2,4-di-tert-butylphenyl) phosphite, and tetrakis(C12-15 alkyl)-4,4'-isopropylidene diphenyl diphosphite; and sulfur-based antioxidants such as dilauryl 3,3'-thiodipropionate, di(tetrazyl) 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearate, and pentaerythritol tetra(β-lauryl thiopropionate). These antioxidants can be used alone or in combination with two or more.

[0328] (Other ingredients)

[0329] The composition containing organopolysiloxane in this invention may also include fillers, curing control agents, viscosity modifiers, and other components. These components may be appropriately included within a range that does not affect the transport loss, heat resistance, or refractive index of the cured product.

[0330] [Cure of compositions containing organopolysiloxanes]

[0331] There are no particular limitations on the curing conditions for the composition containing organopolysiloxane, which is obtained by heat or light curing of the above-described composition containing organopolysiloxane. The curing conditions can be appropriately applied according to the type of polymerization initiator, etc., using the conditions used in the curing of organosilicon resin.

[0332] [Characteristics of cured products]

[0333] When the composition containing organic polysiloxane in this invention is cured as described above, a cured product with the following properties can be obtained.

[0334] (Refractive index)

[0335] The refractive index of the cured material can be controlled by changing the proportion of structural units of the organopolysiloxane. For example, by increasing the value of M2+D2+T2 in the above formulas [1], [2], or [3], that is, by increasing the content of polymerizable functional groups, the density of the resulting cured material can be increased, thereby increasing the refractive index. Conversely, by decreasing the value of M2+D2+T2, that is, by decreasing the content of polymerizable functional groups, the density of the resulting cured material can be decreased, thereby decreasing the refractive index. In addition, the refractive index of the cured material can also be controlled by changing the component proportions of the composition containing organopolysiloxane.

[0336] [Manufacturing method of optical waveguide]

[0337] The manufacturing method of the optical waveguide of the present invention is not particularly limited, and various methods can be used. Specifically, photolithography, replication (molding), direct exposure, reactive ion etching (RIE), injection molding-based methods, photobleaching, direct drawing, self-forming methods, etc. can be used. In addition, it can also be fabricated by methods such as nanoimprinting.

[0338] The following is for reference Figure 1 An example of a method for manufacturing an optical waveguide will be described. First, a composition containing an organopolysiloxane for forming a lower cladding layer 32 is coated onto a substrate. Next, the composition containing the organopolysiloxane is cured by external energy, thereby forming the lower cladding layer 32.

[0339] Next, a composition containing organopolysiloxane for forming the core 20 is coated onto the lower cladding layer 32. Then, the composition containing organopolysiloxane is patterned using a photolithography process to form the core 20 on the lower cladding layer 32. At this time, if the width of the core 20 has a different shape along the light transmission direction, exposure is performed using a photomask with a different shape along the light transmission direction, followed by development, thereby forming the core 20. Furthermore, post-baking can be performed as needed after forming the core 20. The exposure atmosphere can be air or an inert atmosphere. Exposure in an inert atmosphere can reduce the formation of an uncured layer on the polymer layer surface. Furthermore, as described above, post-baking can be performed as needed. Post-baking can sometimes promote curing and improve the adhesion between the polymer layer and the substrate, and the adhesion between polymer layers. Examples of post-baking conditions include baking at temperatures of 50°C to 200°C for tens of seconds to 60 minutes, or baking at temperatures of 80°C to 150°C for tens of seconds to 60 minutes.

[0340] Next, a composition containing an organopolysiloxane for forming the upper cladding layer 31 is coated onto the lower cladding layer 32 and the core 20. Then, the composition containing the organopolysiloxane is cured using external energy to form the upper cladding layer 31. Using the above method, the optical waveguide 10 can be manufactured. It should be noted that, as described above, for convenience, only the terms "lower cladding layer" and "upper cladding layer" are used in this specification. Here, the structure at the bottom of the core during manufacturing is referred to as the lower cladding layer, and the structure on the upper left and right sides of the core is referred to as the upper cladding layer. However, in practical applications, the lower and upper cladding layers can be reversed, or they can be integrated.

[0341] Alternatively, the core and cladding of the optical waveguide can be fabricated on the substrate, and then the waveguide can be peeled off from the substrate.

[0342] As the substrate, silicon wafers, silicon wafers with oxide films, polyimide resins, epoxy resins, PEEK resins, liquid crystal polymers, glass, glass epoxy boards, etc., can be used. The surface of the substrate is preferably pretreated with ozone, plasma, or corona treatment to remove surface deposits, prevent repulsion of the composition containing organopolysiloxanes to be coated, and improve adhesion. Similarly, before forming the core and the upper cladding layer, the surfaces to be formed of the core and the upper cladding layer are preferably pretreated with ozone, plasma, or corona treatment.

[0343] In this first embodiment, the maximum length (H) in the thickness direction and the maximum length (L) in the width direction of the core section of the optical waveguide core 20 can be controlled, for example, by the manufacturing method of the optical waveguide. Specifically, when manufacturing using a photolithography process, the maximum length (H) in the thickness direction of the core can be controlled by adjusting the coating thickness when coating the composition containing organopolysiloxane used to form the core 20. Moreover, for the envisioned maximum length (H) in the thickness direction of the core, by performing photolithography using a photomask with lines drawn with a linewidth close to that (H), H / L can be controlled in the range of 0.4 to 3.

[0344] In this second embodiment, the taper angle of the optical waveguide core 20 can be controlled, for example, by the manufacturing method of the optical waveguide. Specifically, when manufactured by photolithography, the taper angle can be controlled by adjusting the gap between the coating of the composition containing organopolysiloxane used to form the core 20 and the photomask. For example, by increasing the gap, the taper angle can be reduced.

[0345] Furthermore, the cone angle can be controlled by adjusting the focal length of the exposure machine.

[0346] The materials constituting the core and the cladding are not particularly limited. Preferably, at least one of the core and the cladding is composed of a cured product formed by curing the above-mentioned composition containing an organopolysiloxane with polymerizable functional groups. More preferably, both are composed of cured products formed by curing a composition containing an organopolysiloxane. Even more preferably, the above-mentioned composition containing an organopolysiloxane is composed of a cured product formed by curing a composition containing an organopolysiloxane with polymerizable alkenyl groups.

[0347] The materials constituting the lower cladding portion 32 and the upper cladding portion 31 can be the same or different materials, but it is preferable to use a composition containing organopolysiloxanes with different refractive indices after curing. If materials with different refractive indices are used in the lower cladding portion 32 and the upper cladding portion 31, the light blocking state in the optical waveguide 10 can be controlled.

[0348] [Optical components]

[0349] The optical waveguide of the present invention exhibits reduced transmission loss and high patterning capability, for example, it can easily draw fine lines less than 10 μm. Therefore, it can be suitable for use in single-mode optical waveguides, for example. Furthermore, the organopolysiloxane used as a raw material for the optical waveguide of the present invention exhibits high transparency in the near-infrared region, and is therefore also suitable for use in near-infrared optical waveguides.

[0350] Optical components incorporating the optical waveguide of this invention are also within the scope of this invention.

[0351] In addition to the aforementioned optical waveguide and near-infrared optical waveguide, the optical components of the present invention may also include reflectors, connectors, and other connecting components for optical fibers, silicon photonic optical circuits, etc.

[0352] Example

[0353] The present invention will be described in detail through embodiments, but the present invention is not limited to these embodiments.

[0354] [Evaluation methods for organopolysiloxanes]

[0355] (1) 1 Methods for determining H-NMR

[0356] ·Device: AVANCE NEO 400 and BBFO Probe (5mm diameter) manufactured by Bruker Japan Co., Ltd.

[0357] • Measurement conditions: Pulse repetition time / 5 seconds, number of scans / 16 times, measurement mode / single pulse, measurement temperature / 25℃, flip angle / 30°, rotation / 20Hz, measurement temperature / 25℃.

[0358] • Sample preparation: Weigh 60 mg of the organopolysiloxane to be analyzed, and add 12 mg of N,N-dimethylformamide as an internal standard. Further dissolve the dissolved organopolysiloxane by adding deuterated chloroform to a total mass of 1 g, and then add the solution to an NMR sample tube.

[0359] • Calculation of functional group content: The functional group content is estimated based on the ratio of the signal intensity of each component to the signal intensity of the internal standard N,N-dimethylformamide, and the weighing value.

[0360] (2) 29 Si-NMR determination method

[0361] • Sample preparation: Tris(2,4-pentanedione)chromium III was added to deuterated chloroform to a concentration of 0.5% by mass to obtain 29 Solvent for Si-NMR determination. Weigh 1.5 g of the organopolysiloxane of the analyte and add 2.5 ml of the above solvent. 29 The sample is dissolved in a solvent and added to the NMR sample tube for Si-NMR determination.

[0362] (2)-1: The organopolysiloxanes A-1, A-2, and B-1 described later. 29 Si-NMR measurements

[0363] • Device: JNM-ECS400 manufactured by Nippon Electronics Co., Ltd., TUNABLE Probe (10mm diameter): Si-free, AT10 probe.

[0364] • Measurement conditions: Pulse repetition time / 16 seconds, number of scans / 1024 times, measurement mode / non-gated decoupled pulse method (NNE), flip angle / 90°, rotation / none, measurement temperature / 25℃.

[0365] (2)-2: The organopolysiloxane B-2 described later 29 Si-NMR measurements

[0366] ·Device: Made by Bruker Japan Co., Ltd., AVANCE NEO 600, BBO Cryo Probe (5mm diameter).

[0367] • Measurement conditions: Pulse repetition time / 16 seconds, number of scans / 1024 times, measurement mode / reverse gating decoupling measurement, flip angle / 90°, rotation / none, measurement temperature / 25℃.

[0368] <Calculation of structural units>

[0369] The signal strength of each silicon cell was measured, based on the above... 1 The ratio of silicon unit composition is calculated by combining the ratio of signal intensity measured by H-NMR with the ratio of functional group content.

[0370] The organopolysiloxanes A-1 and A-2 used to form the core are prepared by the following steps.

[0371] (Synthesis example 1)

[0372] Hydrolysis and condensation were carried out using 62.68 g of methyl silicate MS51 (Mitsubishi Chemical Corporation), 150.00 g of 3-methacryloyloxypropyltrimethoxysilane KBM-503 (Shin-Etsu Chemical Industry Co., Ltd.), and 32.66 g of hexamethyldisiloxane (NACALAI TESQUE Co., Ltd.), 122.67 g of toluene and 122.67 g of methanol as solvents, and a mixture of 72.98 g of 1N hydrochloric acid and 72.98 g of methanol as catalysts and water. The reaction mixture was then neutralized, washed with deionized water, the solvent and water were removed, and the mixture was filtered to obtain 34 g of the target liquid organopolysiloxane A-1.

[0373] (Synthesis example 2)

[0374] Using 3-methacryloyloxypropyltrimethoxysilane KBM503 manufactured by Shin-Etsu Chemical Industry Co., Ltd., and dimethoxydimethylsilane manufactured by Tokyo Chemical Industry Co., Ltd., organopolysiloxane A-2 was obtained in the same manner as in Synthesis Example 1.

[0375] Organopolysiloxanes B-1 and B-2 for forming the cladding portion are prepared by the following steps.

[0376] (Synthesis example 3)

[0377] Using 104.65 g of methyl silicate MS51 manufactured by Mitsubishi Chemical Corporation, 125.00 g of 3-methacryloyloxypropyltrimethoxysilane KBM-503 manufactured by Shin-Etsu Chemical Industry Co., Ltd., and 21.64 g of hexamethyldisiloxane manufactured by NACALAI TESQUE Co., Ltd., organopolysiloxane B-1 was obtained in the same manner as in Synthesis Example 1.

[0378] (Synthesis example 4)

[0379] Using 3-methacryloyloxypropyltrimethoxysilane KBM503 manufactured by Shin-Etsu Chemical Industry Co., Ltd., and dimethoxydimethylsilane manufactured by Tokyo Chemical Industry Co., Ltd., organopolysiloxane B-2 was obtained in the same manner as in Synthesis Example 1.

[0380] The structural unit proportions of the above-mentioned organopolysiloxanes, as determined by NMR, are shown in Table 1.

[0381] [Table 1]

[0382]

[0383] Using an organopolysiloxane for forming the core, a composition containing an organopolysiloxane for forming an optical waveguide is prepared according to the following steps.

[0384] 100 parts by weight of organopolysiloxane for forming the core, 2 parts by weight of 2-benzyl-2-(dimethylamino)-4'-morpholinylbutyrophenone (Omnirad 369, manufactured by IGM Resins BV), 10 parts by weight of pentaerythritol tetra(3-mercaptobutyrate) (PE1, manufactured by Resonac Co., Ltd.), and 20 parts by weight of propylene glycol monomethyl ether acetate were added to a container and stirred for 2 hours to obtain a composition for forming a polymer optical waveguide. The composition obtained by the above steps using organopolysiloxane A-1 is designated as C-1, and the composition obtained by the above steps using organopolysiloxane A-2 without PE1 is designated as C-2.

[0385] Using an organopolysiloxane for forming the cladding portion, a composition containing an organopolysiloxane for forming an optical waveguide is prepared by the following steps.

[0386] 100 parts by weight of organopolysiloxane for forming the cladding layer, 2 parts by weight of 2-benzyl-2-(dimethylamino)-4'-morpholinylbutyrophenyl (Omnirad 369, manufactured by IGM Resins BV), and 20 parts by weight of propylene glycol monomethyl ether acetate were added to a container and stirred for 2 hours to obtain a composition for forming an optical waveguide. The composition obtained using organopolysiloxane B-1 through the above steps is designated as D-1, and the composition obtained using organopolysiloxane B-2 through the above steps is designated as D-2.

[0387] The refractive index of the cured films made from the above-mentioned organopolysiloxanes A-1, A-2, B-1, and B-2 at a wavelength of 1300 nm was determined by the following steps.

[0388] Compositions C-1, C-2, D-1, and D-2 were spin-coated onto a glass substrate, and an LED with a wavelength of 365 nm was used to accumulate a light intensity of 500 mJ / cm². 2 The coating was exposed to light, thus forming a cured film with a thickness of approximately 10 μm. The refractive index of the cured film was measured using a prism coupler (Metricon KPR-2000). The results showed that the refractive indices of the cured films prepared from compositions C-1, C-2, D-1, and D-2 at a wavelength of 1300 nm were 1.459, 1.466, 1.441, and 1.456, respectively.

[0389] Using the composition containing organic polysiloxane obtained through the above steps for forming optical waveguides, the following five optical waveguides are fabricated through the following steps.

[0390] Example 1

[0391] Using an ozone-treated silicon wafer as a substrate, composition D-1 was coated onto the substrate to a thickness of approximately 5 μm after heat curing, followed by drying to obtain a coated substrate. Next, the resulting coating was exposed without a photomask (the intensity at an exposure wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface are removed, and the coating is then dried. Through these operations, a lower cladding layer is formed on the substrate.

[0392] Next, composition C-1 is coated onto the lower cladding layer to a thickness of approximately 5–7 μm after heat curing. Then, a drying process is performed to obtain a coated substrate. Next, a photomask (with multiple exposure areas 3–10 μm wide and 4 cm long spaced 125 μm apart) is used at an intensity of 500 mW / cm² at a wavelength of 365 nm. 2 Exposure level is 1000 mJ / cm 2 The resulting coating is exposed using a specific method. Then, propylene glycol monomethyl ether acetate, followed by 2-propanol, is used to remove the unexposed portions of the coating, after which it is dried. Through these operations, a substrate with a core formed on the lower cladding layer (a core substrate with a lower cladding layer) is formed.

[0393] Next, composition D-1 was coated onto the core substrate with the lower cladding layer, resulting in a thickness of approximately 10 μm after heat curing. Then, a drying process was performed to obtain the coated substrate. Next, the resulting coating was exposed without a photomask (the intensity at a wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface were removed, and the coating was allowed to dry. Finally, it was heated and cured at 150°C for 1 hour to obtain optical waveguide sample X-1 with a lower cladding / core / upper cladding structure.

[0394] Example 2

[0395] The optical waveguide sample X-2 was obtained by using C-2 as the composition for core formation and D-2 as the composition for cladding formation, except that the same steps as in Example 1 were followed.

[0396] Comparative Example 1

[0397] Using a silicon wafer as a substrate, composition C-1 was coated to a thickness of approximately 5–7 μm after heat curing, followed by drying. Then, using the same photomask as in Example 1, an intensity of 500 mW / cm² was applied at a wavelength of 365 nm. 2 Exposure level is 1000 mJ / cm 2 The obtained coating was exposed using a method that involved exposing the coating to light. Then, propylene glycol monomethyl ether acetate, followed by 2-propanol, was used to remove the unexposed portions of the coating, which was then dried to obtain a substrate with a core. Next, composition D-1 was coated onto the substrate with the core to a thickness of approximately 10 μm after heat curing, and then dried to obtain a coated substrate. Finally, the obtained coating was exposed without a photomask (the intensity at a wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface were removed, and the coating was allowed to dry. Finally, it was heated and cured at 150°C for 1 hour to obtain optical waveguide sample Y-1, which does not have a lower cladding portion compared to Example 1.

[0398] Comparative Example 2

[0399] Using a silicon wafer as a substrate, composition D-1 was coated to a thickness of approximately 5 μm after heat curing, followed by drying to obtain a coated substrate. Next, the resulting coating was exposed without a photomask (the intensity at an exposure wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface are removed, and the coating is then dried. Through these operations, a lower cladding layer is formed on the substrate.

[0400] Next, composition C-1 was coated onto the lower cladding layer to a thickness of approximately 3–4 μm after heat curing. After drying, a coated substrate was obtained. Then, using the same photomask as in Example 1, an intensity of 500 mW / cm² was applied at a wavelength of 365 nm. 2 Exposure level is 1000 mJ / cm 2 The resulting coating is exposed using a specific method. Then, propylene glycol monomethyl ether acetate, followed by 2-propanol, is used to remove the unexposed portions of the coating, after which it is dried. Through these operations, a substrate with a core formed on the lower cladding layer (a core substrate with a lower cladding layer) is formed.

[0401] Next, composition D-1 was coated onto the core substrate with the lower cladding layer, resulting in a thickness of approximately 10 μm after heat curing. Then, a drying process was performed to obtain the coated substrate. Next, the resulting coating was exposed without a photomask (the intensity at a wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface were removed, and the coating was allowed to dry. Finally, it was heated and cured at 150°C for 1 hour to obtain optical waveguide sample Y-2 with a lower cladding / core / upper cladding structure.

[0402] Comparative Example 3

[0403] Using a silicon wafer as a substrate, composition D-1 was coated to a thickness of approximately 5 μm after heat curing, followed by drying to obtain a coated substrate. Next, the resulting coating was exposed without a photomask (the intensity at an exposure wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface are removed, and the coating is then dried. Through these operations, a lower cladding layer is formed on the substrate.

[0404] Next, composition C-1 was coated to a thickness of approximately 5–7 μm after heat curing. A drying process was then performed to obtain a coated substrate. Next, using the same photomask as in Example 1, with the gap between the photomask and the coating film being larger than in Examples 1, 2, and Comparative Example 1, an intensity of 500 mW / cm at a wavelength of 365 nm was measured. 2 Exposure level is 1000 mJ / cm 2 The obtained coating was exposed using a specific method. Then, propylene glycol monomethyl ether acetate, followed by 2-propanol, was used to remove the unexposed portions of the coating, which was then dried. Next, composition D-1 was coated onto a core substrate with a lower cladding layer to a thickness of approximately 10 μm after heat curing, and then dried to obtain a coated substrate. The resulting coating was then exposed without a photomask (the intensity at a wavelength of 365 nm was 40 mW / cm²). 2 The exposure amount is 500mJ / cm. 2 Then, using propylene glycol monomethyl ether acetate, followed by 2-propanol, the insufficiently cured portions of the coating surface were removed, and the coating was allowed to dry. Finally, it was heated and cured at 150°C for 1 hour to obtain optical waveguide sample Y-3 with a lower cladding / core / upper cladding structure and a smaller cone angle than that of Example 1.

[0405] The H / L ratio of the cores of the optical waveguide samples X-1, X-2, Y-1, and Y-2 obtained through the above steps is determined by the following steps.

[0406] The ends of the optical waveguides were cut off, and the cross-section of the resulting sample was observed using a SEM (Hitachi High Technology Manufacturing Co., Ltd., SU1510). The maximum length in the width direction of the core cross-section was defined as L [μm], and the maximum length in the thickness direction as H [μm], and the H / L ratio was calculated. The H / L ratio of the core of optical waveguide samples X-1 and Y-1 was 0.48. Furthermore, the H / L ratio of the core of optical waveguide sample X-2 was 0.69. Furthermore, the H / L ratio of the core of optical waveguide sample Y-2 was 0.38.

[0407] The cone angles of the cores of the optical waveguide samples X-1, X-2, Y-1, and Y-3 obtained through the above steps are determined by the following steps.

[0408] The ends of the optical waveguides were cut off, and the cross-sections of the resulting sample sheets were observed using a SEM (Hitachi High Technology Manufacturing Co., Ltd., SU1510). The core cone angles of optical waveguide samples X-1 and Y-1 are 83°. The core cone angle of optical waveguide sample X-2 is 83°. The core cone angle of optical waveguide sample Y-3 is 47°.

[0409] The transmission loss of optical waveguide samples X-1, X-2, and Y-1 obtained through the above steps, as well as the connection loss of optical waveguide samples X-1 and X-2, are determined by the following steps.

[0410] Several samples of varying optical path lengths were fabricated by cutting both ends of the optical waveguides and connecting them to single-mode fibers. A temperature-controlled fiber-to-optic high-power LD stabilization source (LDS1005) manufactured by Precise Gauges was connected to the incident single-mode fiber, and a power meter (MT9810B) manufactured by Anritsu was connected to the output single-mode fiber. The insertion loss of each sample was measured. The transmission loss was calculated based on the change in insertion loss relative to the optical path length. The results showed that the transmission losses of waveguide samples X-1 and X-2 were 0.31 dB / cm and 0.30 dB / cm, respectively. On the other hand, the transmission loss of waveguide sample Y-1 was 1.5 dB / cm. Furthermore, the connection loss was calculated based on the intercept of an approximate straight line drawn from a graph with the waveguide length on the horizontal axis and the insertion loss on the vertical axis. The connection losses of waveguides X-1 and X-2 were 2.00 dB and 1.20 dB, respectively.

[0411] The polarization-dependent loss of the optical waveguide samples X-1, X-2, Y-2, and Y-3 obtained through the above steps is determined by the following steps.

[0412] The two ends of the optical waveguide were cut to create a sample with an optical path length of approximately 3 cm, and single-mode fibers were connected to both ends. A temperature-controlled fiber-to-optic high-power LD stabilization source (LDS1005) manufactured by Precise Gauges was connected to the incident single-mode fiber, and a power meter (MT9810B) manufactured by Anritsu was connected to the output single-mode fiber. A polarization controller (FPC561) manufactured by Thorlabs was used to change the polarization state of the light incident on the sample, and the polarization-dependent loss was measured. The polarization-dependent losses of the optical waveguide samples X-1, X-2, Y-2, and Y-3 were 0.2 dB, 0.3 dB, 0.6 dB, and 0.6 dB, respectively.

[0413] [Table 2]

[0414]

[0415] [Examination of Results]

[0416] Compared to waveguide sample Y-1 without a lower cladding, waveguide samples X-1 and X-2 with a lower cladding exhibit significantly reduced transmission loss. Based on this result, by incorporating a lower cladding, light transmitted within the core is effectively confined within the core, achieving high optical transmission performance.

[0417] Furthermore, based on the comparison between optical waveguide samples X-1 and X-2 with an H / L ratio of 0.4 or higher in the cross-sectional shape of the core and optical waveguide sample Y-2 with an H / L ratio of less than 0.4, and the comparison between X-1 and X-2 with a cone angle of 50° or higher and 130° or lower in the cross-sectional shape of the core and Y-3 with a cone angle of less than 50°, it is considered that the near-field pattern on the core emission side is close to a perfect circle, which can reduce the polarization-dependent loss in optical transmission within the core.

[0418] Industrial availability

[0419] The optical waveguide of this invention exhibits both low transmission loss and low polarization dependence loss, demonstrating excellent optical transmission characteristics. Due to these characteristics, the optical waveguide of this invention can be used in optical components, such as those used for optical interconnects.

Claims

1. An optical waveguide comprising a core for transmitting light and a cladding portion having a refractive index lower than that of the core. The cladding portion has a lower cladding portion that is connected to a portion of the core portion. In the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, the direction of the line connecting the core and the lower cladding is defined as the width direction, and the direction perpendicular to the width direction is defined as the thickness direction. When the maximum length in the width direction of the core's cross-section is defined as L, and the maximum length in the thickness direction is defined as H, the unit of L is μm, and the unit of H is μm. H / L is 0.4 to 3. At least one of the core and the cladding is composed of a cured product formed by curing a composition containing an organopolysiloxane having polymerizable functional groups as represented by the following formula [1]. (R 1 R 2 R 3 SiO 1 / 2 ) M1 (R 4 R 5 R 6 SiO 1 / 2 ) M2 (R 7 R 8 SiO 2 / 2 ) D1 (R 9 R 6 SiO 2 / 2 ) D2 (R 10 SiO 3 / 2 ) T1 (R 6 SiO 3 / 2 ) T2 (SiO 4 / 2 ) Q (O 1 / 2 R 11 ) Y1 (O 1 / 2 R 6 ) Y2 [1] In formula [1], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms. R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymeric functional groups. R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other. 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0≤Q 0 <M2+D2+T2、 0 <D1+D2+T1+T2+Q、 M1+M2+D1+D2+T1+T2+Q=1.

2. An optical waveguide comprising a core for transmitting light and a cladding portion having a refractive index lower than that of the core. The cladding portion has a lower cladding portion that is connected to a portion of the core portion. In the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, the direction of the line connecting the core and the lower cladding is defined as the width direction, the direction perpendicular to the width direction is defined as the thickness direction, and the angle formed by the tangent of the core side portion whose maximum length relative to the thickness direction is equivalent to 1 / 2 of the core portion and the lower cladding portion is defined as the cone angle of the core, wherein the cone angle is 50° or more and 130° or less. At least one of the core and the cladding is composed of a cured product formed by curing a composition containing an organopolysiloxane having polymerizable functional groups as represented by the following formula [1]. (R 1 R 2 R 3 SiO 1 / 2 ) M1 (R 4 R 5 R 6 SiO 1 / 2 ) M2 (R 7 R 8 SiO 2 / 2 ) D1 (R 9 R 6 SiO 2 / 2 ) D2 (R 10 SiO 3 / 2 ) T1 (R 6 SiO 3 / 2 ) T2 (SiO 4 / 2 ) Q (O 1 / 2 R 11 ) Y1 (O 1 / 2 R 6 ) Y2 [1] In formula [1], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms. R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymeric functional groups. R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other. 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0≤Q 0 <M2+D2+T2、 0 <D1+D2+T1+T2+Q、 M1+M2+D1+D2+T1+T2+Q=1.

3. The optical waveguide according to claim 1 or 2, wherein, The refractive index difference between the core and the cladding is greater than or equal to 0.005 and less than or equal to 0.

05.

4. The optical waveguide according to claim 1 or 2, wherein, In the cross-sectional shape of the core in the direction perpendicular to the light transmission direction, the length of the lower cladding portion in the thickness direction is 1 μm or more.

5. The optical waveguide according to claim 1 or 2, wherein, The cladding portion has an upper cladding portion that exists in the core and is not connected to the lower cladding portion.

6. The optical waveguide according to claim 1 or 2, wherein, The core has a refractive index of 1.400 or higher and 1.520 or lower at a wavelength of 1300 nm.

7. The optical waveguide according to claim 1 or 2, wherein, The organopolysiloxane having polymerizable functional groups is represented by the following formula [2], (R 1 R 2 R 3 SiO 1 / 2 ) M1 (R 4 R 5 R 6 SiO 1 / 2 ) M2 (R 7 R 8 SiO 2 / 2 ) D1 (R 9 R 6 SiO 2 / 2 ) D2 (R 10 SiO 3 / 2 ) T1 (R 6 SiO 3 / 2 ) T2 (SiO 4 / 2 ) Q (O 1 / 2 R 11 ) Y1 (O 1 / 2 R 6 ) Y2 [2] In formula [2], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms. R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymeric functional groups. R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other. 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0<Q、 0 <M2+D2+T2、 M1+M2+D1+D2+T1+T2+Q=1].

8. The optical waveguide according to claim 1 or 2, wherein, The organopolysiloxane having a polymerizable functional group is represented by the following formula [3], (R 1 R 2 R 3 SiO 1 / 2 ) M1 (R 4 R 5 R 6 SiO 1 / 2 ) M2 (R 7 R 8 SiO 2 / 2 ) D1 (R 9 R 6 SiO 2 / 2 ) D2 (R 10 SiO 3 / 2 ) T1 (R 6 SiO 3 / 2 ) T2 (O 1 / 2 R 11 ) Y1 (O 1 / 2 R 6 ) Y2 [3] In formula [3], R 1 ~R 5 R 7 ~R 11 Each group is independently selected from one or more groups composed of organic groups and hydrogen atoms. R 1 ~R 3 R 7 R 8 R 10 and R 11 It does not contain polymeric functional groups. R 6 It is an organic group containing one or more polymerizable functional groups, and in the case of multiple groups, they may optionally be the same as or different from each other. 0≤M1, 0≤D1, 0≤T1, 0≤Y1, 0≤Y2, 0<M2 + D2 + T2, 0<D1 + D2 + T1 + T2, M1 + M2 + D1 + D2 + T1 + T2 = 1.

9. The optical waveguide according to claim 1 or 2, wherein, in the formula [1], 0.02≤Y1≤0.

25.

10. The optical waveguide according to claim 1 or 2, wherein, in the formula [1], 0<M2 + D2 + T2≤0.

25. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The R 6 It contains polymeric alkenyl groups. ​ The R 6 It contains acryloyl and / or methacryloyl groups. ​ ​ ​ The R 6 It is acryloyloxypropyl and / or methacryloyloxypropyl. ​ ​

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