JP3465242B2 - Polymer optical material, optical waveguide using the same, and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymeric optical material, an optical waveguide using the same, and a method for producing the same, which are used in the fields of general optics and micro optics, and in optical communication and optical information. It can be used for various optical components, optical integrated circuits, optical wiring boards, etc. used in the field of processing.

[0002]

2. Description of the Related Art A polymer material is easy to form a thin film by a spin coating method or a dipping method, and is suitable for producing an optical component having a large area. In addition, since the heat treatment process at high temperature is not included in the film formation, the optical waveguide is fabricated on a substrate such as a semiconductor substrate or a plastic substrate that is difficult to heat-treat compared to the case of using an inorganic glass material such as quartz. There is an advantage that you can. Furthermore, it is also possible to fabricate a flexible optical waveguide that takes advantage of the flexibility and toughness of a polymer. For these reasons, it is expected that optical waveguide components such as optical integrated circuits used in the field of optical communication and optical wiring boards used in the field of optical information processing can be mass-produced at low cost using polymer optical materials. ing. Conventionally, polymeric optical materials have been known to have problems in environmental resistance such as heat resistance or humidity resistance, or in transparency in the optical communication wavelength band (visible region to near infrared region). Significantly improved materials have been invented and reported [eg,
JP-A-3-43423]. Since the material is a polymer material having a silsesquioxane structure as a molecular skeleton, it has excellent heat resistance. Further, since the phenyl group and the alkyl group of the side chain are hydrophobic, the moisture resistance is high. Furthermore, since the hydrogen of the C—H bond contained in the side chain is replaced by halogen or deuterium, absorption in the near infrared region due to the overtone of the C—H bond or the overtone of the bending vibration or the bond sound. , Has been greatly reduced. By stacking such polymer materials, an optical waveguide having a core / clad structure can be manufactured. FIG. 1 is a sectional view of an optical waveguide having a core / clad structure. In FIG. 1, reference numeral 1 is a substrate, 2 is a lower clad layer, 3 is a core, and 4 is an upper clad layer. By stacking polymeric materials,
The following method is the most general method for producing an optical waveguide. First, a solution of a clad material is applied onto the substrate 1 by spin coating or dipping to form a film, thereby forming a lower clad layer 2. Then, a solution of a core material having a refractive index higher than that of the lower clad is applied onto the lower clad layer 2 by spin coating or dipping to form a film, thereby forming a core layer. Then, this core layer is processed into a desired pattern by a fine processing technique such as photolithography and etching to form the core portion 3. Finally,
A solution of a clad material is applied onto the core portion 3 by a spin coating method or a dipping method to form a film, and an upper clad layer 4 is formed, whereby the optical waveguide as shown in FIG. 1 is completed. One of the problems in producing an optical waveguide having such a core / clad structure using the material according to the invention is the occurrence of cracks. The cracks are generated by the stress generated in the polymer thin film, and the higher the film thickness, the higher the probability of occurrence. However, when manufacturing the optical waveguide, it is necessary to form a thin film having a certain thickness or more. For example, when a single-mode optical waveguide whose core portion is a square of 8 μm square is formed on a silicon substrate, a film thickness of about 15 μm or more is required for the lower cladding in order to avoid the influence of metal cladding. Here, the metal cladding means that when the thickness of the lower cladding is small, the light guided in the core portion is drawn into the silicon substrate, and the waveguide loss becomes significantly large. Also,
Also for the upper clad, in order to prevent the influence of dust or dirt on the surface, the stress from the outside, etc. on the light guided in the core part, the upper clad needs to have a film thickness of about 8 μm or more from the upper surface of the core. Become. In the above-mentioned polysilsesquioxane-based polymer optical material, as the molecular weight became higher, the thin film formed using the same tended to become stronger. In fact, when the material had a weight average molecular weight of 100,000 or more, no crack was generated in a thin film having a thickness of about 15 μm produced using the material.

[0003]

However, the above-mentioned optical materials have a drawback that their solvent resistance is relatively low. For this reason, there has been a surface having insufficient solvent resistance in optical parts and the like manufactured using the material. In addition, there are processing problems as described below. That is, when an optical waveguide having a core / clad structure is produced using the material, it is necessary to apply a solution of the core or clad material by spin coating or dipping as described above. At that time, there is a problem that intermixing occurs between the laminated polymer layers. Here, intermixing means that when another polymer solution is applied onto a polymer thin film to form a film, the surface of the lower layer is dissolved in the coating solution for forming the upper layer and the interface becomes nonuniform. Say. For example, when applying a core layer on the lower clad layer, if such intermixing occurs, the waveguide shape becomes smaller than the design dimension, or the refractive index difference between the core and the clad that requires precise control changes. Occurs, which makes it difficult to achieve a desired function as an optical waveguide. In order to avoid such intermixing, it is necessary to take measures such as forming a layer that is insoluble in a solvent and has a thickness of a fraction of a wavelength or less. It had the drawback of being complicated. Furthermore,
The optical material according to the invention has another drawback that the birefringence is large. Here, the birefringence means the difference between the refractive index for light whose polarization direction is perpendicular to the substrate (TM mode) and the refractive index for light whose polarization direction is parallel to the substrate (TE mode). In fact, in the case of a polysilsesquioxane-based polymer material in which all the side chains are deuterated phenyl groups, the thin film produced using it has a large birefringence of about 10 ^-2 . For this reason, optical components manufactured using this material have polarization dependence, and even if the intensity of incident light is constant, their output characteristics fluctuate due to fluctuations in the polarization plane. In addition, it was a problem when actually used. In order to eliminate such polarization dependence, it is necessary to use it in combination with a polarizer or the like, but in reality, there is a drawback that the configuration of the optical component becomes considerably complicated. The present invention has been made in view of such a current situation, the object thereof is excellent in solvent resistance, small birefringence, and low loss, a polymer optical material excellent in heat resistance and moisture resistance, and An object is to provide an optical waveguide using the same and a manufacturing method thereof.

[0004]

The present invention will be described in brief. The first invention of the present invention relates to a polymeric optical material, wherein each unit of formula (I) and formula (II) is a constituent component. The following general formula (Formula 1):

[0005]

[Chemical 1]

[Wherein R ₁ is a deuterated phenyl group or halogenated phenyl group represented by C ₆ X ₅ (X represents deuterium or halogen), Z is a hydroxyl group or OC _m H
A repeating unit represented by _{2m + 1} (m is an alkoxy group represented by 3 or less), and formula (III) and formula (IV)
The following general formula (Chemical formula 2) in which each unit of

[0007]

[Chemical 2]

[In the formula, R ₂ is an alkyl group represented by C _n Y _{2n + 1} (Y is hydrogen, deuterium or halogen, and n is a positive integer), a deuterated alkyl group or an alkyl halide. And Z is a hydroxyl group or an alkoxy group represented by OC _m H _{2m + 1} (m is an integer of 3 or less)] and has a weight average molecular weight of 1,000.
It is characterized in that it is a copolymer of 0 or less. Also,
A second invention of the present invention is an invention relating to an optical waveguide, comprising: a core portion made of a polymer material; and a cladding portion surrounding the core portion and made of a polymer material having a lower refractive index than the core portion. The core part and the clad part are polymer optical materials obtained by thermally crosslinking the polymer optical material of the first invention. The third invention of the present invention is
The invention relates to a method for manufacturing an optical waveguide, wherein an optical waveguide having a core portion made of a polymer material and a clad portion surrounding the core portion and made of a polymer material having a refractive index lower than that of the core portion is used as a polymer material. In the method for producing an optical waveguide produced by stacking the above, the method includes the step of forming a core layer and a clad layer by applying the polymeric optical material of the first invention and then thermally crosslinking it.

The present inventors have used a conventional polysilsesquioxane-based polymeric optical material as a high molecular weight polymer, whereas a low molecular weight oligomer or prepolymer is used after being cured by thermal crosslinking. By improving the material of the mold, the solvent resistance, which has been a problem in the past, can be greatly improved, and by setting the weight average molecular weight of the oligomer or prepolymer to 10,000 or less, polysilsesquis obtained by thermal crosslinking can be obtained. We have found that the birefringence of oxane-based polymeric optical materials can be significantly reduced, and that optical waveguides made from these materials have excellent solvent resistance, low polarization dependence, and low waveguide loss. The inventors have found that they have high heat resistance and high humidity resistance, and have completed the present invention. That is, in the present invention, the conventional polysilsesquioxane-based polymeric optical material is a high molecular weight polymer, and when forming a thin film, it is dissolved in an organic solvent and applied, and then the solvent is dried and used. On the other hand, by improving the type material used by curing a low molecular weight oligomer or prepolymer by thermal crosslinking, the solvent resistance, which has been a problem in the past, is greatly improved, and when producing an optical waveguide. This makes it possible to avoid intermixing of. In addition, since the present invention is a conventional polysilsesquioxane-based polymeric optical material, which is a polymer having a high molecular weight and a long molecular length, the molecular chains are oriented during the formation of a thin film, resulting in optical anisotropy. While exhibiting the property and having a large birefringence,
By applying a low molecular weight oligomer or prepolymer having a weight average molecular weight of 10,000 or less and then curing it by thermal crosslinking to improve the type of material used, the orientation of the molecular chains during the formation of a thin film is suppressed. , Birefringence 1 × 10
^-3 or less, and it becomes possible to eliminate the polarization dependence of the optical waveguide manufactured using the material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The contents of the present invention will be specifically described below. When the optical material in the first invention of the present invention is used, a solvent can be contained as a component other than the copolymer represented by the general formulas (Formula 1) and (Formula 2). By containing the solvent, the polymeric optical material becomes a fluid having an appropriate viscosity corresponding to the thin film forming step. Examples of the solvent used at this time include aromatics such as toluene and anisole, alcohols such as ethanol and i-propyl alcohol, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and butyl acetate, 2-
Cellosolves such as ethoxyethanol and 2-butoxyethanol; cellosolve acetates such as 2-ethoxyethyl acetate and 2-butoxyethyl acetate; ethers such as dibutyl ether and ethylene glycol dimethyl ether; heterocycles such as tetrahydrofuran and N-methylpyrrolidone. And the like. The polymeric optical material can obtain an appropriate viscosity corresponding to the thin film forming step by selecting the type of solvent and adjusting the solution concentration.

When the polymer optical material is obtained by thermally crosslinking the polymer optical material according to the first invention described above, the formula (II) in the formula (1) and the formula (II) A three-dimensional crosslinked structure is formed by the condensation reaction of the terminal of the hydroxyl group or alkoxy group contained in the component represented by the formula (IV) in the chemical formula 2). The temperature and time required for thermal crosslinking generally depend on the type of side chain, but are generally 150 ° C to 300 ° C.
The heating is performed in the electric furnace at the temperature of 1 hour to several hours. Since the polymeric optical material cured by thermal crosslinking has a three-dimensional crosslinked structure, it becomes insoluble in the solvent as described above. In addition, by forming a three-dimensional crosslinked structure, a thin film formed by using the material becomes tough and cracks can be prevented from occurring. Further, the above-mentioned polymeric optical material uses a low molecular weight oligomer or prepolymer when the polymeric optical material is applied in the step of forming a thin film, and since they have a short molecular length, the orientation of the molecular chain is Is suppressed, the birefringence of the polymer optical material obtained after thermal crosslinking becomes small. FIG. 2 shows a comparison of the birefringence between the conventional polysilsesquioxane-based optical material and the polymeric optical material according to the present invention (after thermal crosslinking). The horizontal axis of FIG. 2 represents the weight average molecular weight of the polysilsesquioxane-based optical material, and the vertical axis represents the birefringence at a wavelength of 1.3 μm.
Black squares in the figure represent conventional polysilsesquioxane-based optical materials, and white circles represent the polymeric optical material of the present invention (after thermal crosslinking). As shown in FIG. 2, the present inventors have found that the birefringence of a conventional polysilsesquioxane-based optical material decreases in proportion to the square root of the weight average molecular weight thereof, and it is low in the thin film forming process. It has been concluded that coating the optical material in the state of a molecular weight oligomer or prepolymer is effective in reducing birefringence. Further, by forming a three-dimensional crosslinked structure by thermal crosslinking, it becomes possible to improve the toughness of a thin film produced using the material and prevent the occurrence of cracks, and the birefringence is 1 × 10 5.
^-We have obtained optical materials of ^-3 or less. In the case of forming such a three-dimensional crosslinked structure, a method of forming a three-dimensional urethane bond by using a crosslinking agent that reacts with a hydroxyl group or an alkoxy group terminal, for example, polyisocyanate is also considered. However, the birefringence of a thin film formed using such an optical material is about 1 × 10 ⁻³ , whereas the method of the present invention which does not use a crosslinking agent has a birefringence of 1 × 10 ^−3.
It is possible to provide the following optical materials.

According to the second and third inventions of the present invention, when a polymer optical waveguide is manufactured using the optical material according to the first invention, the process can be performed as follows. First, the refractive index of the material is adjusted according to the waveguide mode condition required for the optical waveguide, and at least two materials having a precisely controlled refractive index difference are prepared as the core / clad material. The magnitude of the refractive index difference is determined depending on the mode of light to be guided and the size of the core, but is generally in the range of 0.1% to 5%. For example, when the mode diameters of the single mode optical fiber and the guided light are matched, it is desirable that the shape of the core portion is a square of 8 μm square and the refractive index difference is 0.3%. In the optical material, the component represented by the general formula (Formula 1) has a higher refractive index than the component represented by the general formula (Formula 2). The rate can be adjusted. Next, the clad material with the adjusted refractive index is applied onto the substrate by a spin coating method or the like, and this is thermally crosslinked using the above method to form a lower clad. Then, a core material having a controlled refractive index is applied thereon by a spin coating method or the like, and this is thermally crosslinked using the above method to form a core layer.
Here, since the lower clad layer is hardened, intermixing does not occur when the core material is applied. Then, a layer serving as an etching mask is formed on the core layer and processed into a waveguide pattern by photolithography or the like. As a material for the etching mask, organic photoresist, metal or the like is used. Further, the core layer is processed into a desired waveguide pattern by reactive ion etching to form a core portion. Finally, a clad material is applied on the core portion and then thermally crosslinked to form an upper clad layer. Here, since the lower clad layer and the core are hardened, intermixing does not occur when the upper clad material is applied. The optical waveguide manufactured in this manner has excellent solvent resistance, small polarization dependence due to the small birefringence of the material used, low waveguide loss, and excellent heat resistance and moisture resistance.

[0013]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Deuterated phenyltrichlorosilane (200 g) and methyltriethoxysilane (140 g) were dissolved in 1 liter of dehydrated tetrahydrofuran, and 3 equivalents of water were slowly added thereto so that the liquid temperature would not rise. Dropped. Then, while stirring the reaction solution, 3 equivalents of sodium hydrogen carbonate was added thereto. After the generation of carbon dioxide gas was completed, stirring was continued for another hour. Then, the reaction solution was filtered, and the tetrahydrofuran in the filtrate was distilled off with a rotary evaporator to obtain a colorless transparent viscous liquid. Further, this liquid was vacuum dried to obtain a polymer A. When the molecular weight of this material was measured by GPC, Mw = 140
0 and Mn = 1300. 100 g of the above polymer A
A composition B consisting of and 50 g of a solvent (methyl ethyl ketone) was prepared. This composition was cured by heating at 200 ° C. for 2 hours and became insoluble in the solvent. The refractive index of the cured composition at a wavelength of 1.3 μm was 1.4940 in TE mode and 1.4939 in TM mode. Further, deuterated phenyltrichlorosilane (200 g) and methyltriethoxysilane (180 g) were dissolved in 1 liter of dehydrated tetrahydrofuran, and 3 equivalents of water was slowly added dropwise thereto so that the liquid temperature did not rise. Then, while stirring the reaction solution, 3 equivalents of sodium hydrogen carbonate was added thereto. After the generation of carbon dioxide,
Stirring continued for another hour. Then, the reaction solution was filtered, and the tetrahydrofuran in the filtrate was distilled off with a rotary evaporator to obtain a colorless transparent viscous liquid. Further, this liquid was vacuum dried to obtain a polymer C. When the molecular weight of this material was measured by GPC, Mw =
The values were 1800 and Mn = 1600. The polymer C1
Composition D consisting of 00 g and 50 g of solvent (methyl ethyl ketone) was prepared. This composition was cured by heating at 200 ° C. for 2 hours and became insoluble in the solvent. The refractive index of the cured composition at a wavelength of 1.3 μm is TE
It was 1.4903 in the mode and 1.4904 in the TM mode.

An optical waveguide using the polymer A as a core and the polymer C as a clad was prepared as follows. First, the composition D was applied onto a silicon substrate by a spin coating method to form a film. At this time, the rotation speed of the spin coater was adjusted so that the film thickness was 15 μm. The formed thin film was cured by heating at 200 ° C. for 2 hours to form a lower clad layer. Next, a composition B was used thereon to form a core layer by spin coating. The rotation speed of the spin coater was adjusted so that the thickness of the core layer was 8 μm. At this time, no intermixing was observed between the lower clad layer and the core layer. The formed core layer was cured by heating at 200 ° C. for 2 hours. Then, deposit a copper thin film on this by sputtering,
A linear waveguide mask pattern was formed by photolithography and ion milling. Further, by reactive ion etching, the core layer other than the mask pattern was removed to form a rectangular core ridge having a width of 8 μm and a height of 8 μm. The composition D was applied onto this and cured in the same manner as in the case of forming the lower clad to prepare a buried channel optical waveguide having a core / clad structure. The thickness of the upper clad was set to 8 μm from the upper surface of the core. At this time, no intermixing was observed between the core ridge and the lower clad layer and the upper clad layer. When this optical waveguide was cut into a length of 5 cm and the insertion loss was measured, it was 1.0 dB or less at a wavelength of 1.3 μm and 3.0 dB or less at a wavelength of 1.55 μm. Also, the polarization dependence of the insertion loss is 1.55 μm even if the wavelength is 1.3 μm.
However, it was 0.1 dB or less. Furthermore, the loss of this optical waveguide did not fluctuate for more than 1 month even under the condition of 75 ° C./90% RH.

Example 2 Deuterated phenyltrichlorosilane (300 g) and (deuterated methyl) trichlorosilane (50 g) were dissolved in 1 liter of dehydrated tetrahydrofuran, and 3 parts thereof were added thereto.
An equivalent amount of water was slowly added dropwise so that the liquid temperature did not rise. Then, while stirring the reaction solution, 3 equivalents of sodium hydrogen carbonate was added thereto. After the generation of carbon dioxide gas was completed, stirring was continued for another hour. Then, the reaction solution was filtered, and the tetrahydrofuran in the filtrate was distilled off with a rotary evaporator to obtain a colorless transparent viscous liquid.
Furthermore, this liquid was vacuum dried to obtain a polymer E. When the molecular weight of this material was measured by GPC, Mw
= 1200 and Mn = 1000. Polymer E above
A composition F consisting of 100 g and a solvent (methyl ethyl ketone) 50 g was prepared. This composition was cured by heating at 200 ° C. for 2 hours and became insoluble in the solvent. The refractive index of the cured composition is 1.5230 in TE mode and 1.5235 in TM mode at a wavelength of 1.3 μm.
Met. Further, deuterated phenyltrichlorosilane (300 g) and (deuterated methyl) trichlorosilane (100 g) were dissolved in 1 liter of dehydrated tetrahydrofuran, and 3 equivalents of water were slowly added thereto so that the liquid temperature would not rise. Dropped. Then, while stirring the reaction solution, 3 equivalents of sodium hydrogen carbonate was added thereto.
After the generation of carbon dioxide was completed, stirring was continued for another hour. Then, the reaction solution was filtered, and the tetrahydrofuran in the filtrate was distilled off with a rotary evaporator to obtain a colorless transparent viscous liquid. Further, this liquid was vacuum dried to obtain a polymer G. The molecular weight of this material is GPC
Mw = 2500 and Mn = 2300. A composition H composed of 100 g of the polymer G and 50 g of the solvent (methyl ethyl ketone) was prepared. This composition is cured by heat treatment at 200 ° C. for 2 hours,
It became insoluble in the solvent. The cured composition has a refractive index of 1.5171 in the TE mode at a wavelength of 1.3 μm, T
It was 1.5174 in M mode. An optical waveguide using the polymer E as a core and the polymer G as a clad was produced according to Example 1. When this optical waveguide was cut into a length of 5 cm and the insertion loss was measured, the wavelength was 1.3 μm.
m was 0.8 dB or less, and a wavelength of 1.55 μm was 2.8 dB or less. Also, the polarization dependence of the insertion loss is 1.3
It was 0.1 dB or less at both μm and wavelength of 1.55 μm. Furthermore, the loss of this optical waveguide did not change for more than 1 month even under the condition of 120 ° C.

Example 3 A directional coupler was produced by using the polymer E described in Example 2 as a core and the polymer G as a clad. The method for producing the optical waveguide was performed according to Example 1, and the directional coupler pattern was produced using a directional coupler pattern having a core interval of 4 μm in the coupling portion instead of the linear waveguide pattern. When this directional coupler was cut out and its characteristics were measured, a good directional coupler operation was obtained, and the perfect coupling length at a wavelength of 1.3 μm was 5.5 mm in TE mode and 5.6 in TM mode.
It was mm. The characteristic of this directional coupler is 200
No change was observed even after the heat treatment at 1 ° C. for 1 hour.

Comparative Example 1 Poly (deuterated phenylsilsesquioxane) having a weight average molecular weight of 220,000 was used as a core, and the polymer E described in Example 2 was used as a clad. A directional coupler was produced according to Example 2. However, the core layer was coated with a 10% anisole solution, spin-coated and then heated at 150 ° C. for 1 hour to sufficiently dry the solvent. The refractive index of the core layer is 1.530 in TE mode at a wavelength of 1.3 μm.
3, 1.5390 in TM mode. When this directional coupler was cut out and its characteristics were measured, the operation as a directional coupler was confirmed, but the characteristics have polarization dependence, and the complete coupling length at a wavelength of 1.3 μm is TE mode. Was 6.5 mm and TM mode was 11.3 mm.

Example 4 Monofluorophenyltriethoxysilane-d ₄ (25
0 g) and (3,3,4,4,4-pentafluorobutyl) trichlorosilane (260 g) were dissolved in 1 liter of dehydrated tetrahydrofuran, and 3 equivalents of water were slowly added thereto so that the liquid temperature would not rise. Dropped. Then, while stirring the reaction solution, 3 equivalents of sodium hydrogen carbonate was added thereto. After the generation of carbon dioxide gas was completed, stirring was continued for another hour. Then, the reaction solution was filtered, and the tetrahydrofuran in the filtrate was distilled off with a rotary evaporator to obtain a colorless transparent viscous liquid. Further, the liquid I was vacuum dried to obtain a polymer I. When the molecular weight of this material was measured by GPC, Mw = 150
0 and Mn = 1300. 100 of Polymer I above
g and a solvent (methyl ethyl ketone) 50 g were prepared. This composition was cured by heating at 200 ° C. for 2 hours and became insoluble in the solvent. The refractive index of the cured composition was 1.4580 in TE mode and 1.4579 in TM mode at a wavelength of 1.3 μm. In addition, monofluorophenyltriethoxysilane-
d ₄ (200 g) and (3,3,4,4,4-pentafluorobutyl) trichlorosilane (250 g) were dissolved in 1 liter of dehydrated tetrahydrofuran, and 3 parts thereof were added thereto.
An equivalent amount of water was slowly added dropwise so that the liquid temperature did not rise. Then, while stirring the reaction solution, 3 equivalents of sodium hydrogen carbonate was added thereto. After the generation of carbon dioxide was completed, stirring was continued for another hour. Then, the reaction solution was filtered, and the tetrahydrofuran in the filtrate was distilled off with a rotary evaporator to obtain a colorless transparent viscous liquid. Further, this liquid was vacuum dried to obtain a polymer K. When the molecular weight of this material was measured by GPC,
Mw = 2000 and Mn = 1800. A composition L consisting of 100 g of the above polymer K and 50 g of the solvent (methyl ethyl ketone) was prepared. This composition was cured by heating at 200 ° C. for 2 hours and became insoluble in the solvent. The refractive index of the cured composition is 1.4543 in TE mode and 1.45 in TM mode at a wavelength of 1.3 μm.
It was 44. An optical waveguide using the polymer J as a core and the polymer K as a clad was produced according to Example 1. When this optical waveguide was cut into a length of 5 cm and the insertion loss was measured, it was 0.5 dB or less at a wavelength of 1.3 μm and 2.0 dB or less at a wavelength of 1.55 μm. The polarization dependence of the insertion loss was 0.1 dB or less at both the wavelength of 1.3 μm and the wavelength of 1.55 μm. Furthermore, the loss of this optical waveguide did not fluctuate for more than 1 month even under the condition of 90 ° C./75% RH.

[0020]

As described above, by using the optical material according to the present invention, a polysilsesquioxane system having excellent solvent resistance, small birefringence, low loss, high heat resistance and high humidity resistance can be obtained. Polymer optical materials can be realized. Also,
The optical component using the optical material according to the present invention is excellent in solvent resistance, has small polarization dependence, and has low loss, high heat resistance, and high moisture resistance. Therefore, it is particularly applicable to optical waveguide type components. It is advantageous. Therefore, the present invention is applicable to general optics, micro optics,
It can be applied to fields such as optical communication and optical information processing.

[Brief description of drawings]

FIG. 1 is a component diagram showing an example of a polymer optical waveguide.

FIG. 2 is a diagram showing the relationship between the weight average molecular weight and the birefringence of a polysilsesquioxane-based optical material.

[Explanation of symbols]

1: substrate, 2: lower clad, 3: core, 4: upper clad

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sugo Sugawara 1-3-3 Gotenyama, Musashino City, Tokyo NTT Advance Technology Co., Ltd. (72) Inventor Mitsuo Usui Nishi, Shinjuku-ku, Tokyo Shinjuku 3-chome 19-2 Nihon Telegraph and Telephone Corporation (72) Inventor Michiyuki Amano 3--19-3 Nishishinjuku Nishi-Shinjuku, Shinjuku-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) Reference JP-A-7 -278306 (JP, A) JP-A-9-324051 (JP, A) JP-A-9-208704 (JP, A) JP-A-9-124793 (JP, A) JP-A-4-272929 (JP, A) ) JP-A-9-59369 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 1/04 C08G 77/04 C08G 77/24 G02B 6/12 G02B 6/13

Claims (3)

(57) [Claims] 1. The following general formula (Chemical formula 1) having each unit of the formula (I) and the formula (II) as a constituent: [In the formula, R ₁ is a deuterated phenyl group or halogenated phenyl group represented by C ₆ X ₅ (X represents deuterium or halogen), Z is a hydroxyl group or OC _m H _{2m + 1} (m is 3
Is a alkoxy group represented by the following integer), and the following general formula (Formula 2) having each unit of the formula (III) and the formula (IV) as constituent components: [In the formula, R ₂ is an alkyl group represented by C _n Y _{2n + 1} (Y is hydrogen, deuterium or halogen, and n is a positive integer), a deuterated alkyl group or a halogenated alkyl group. , Z is a hydroxyl group or an alkoxy group represented by OC _m H _{2m + 1} (m is an integer of 3 or less), and is a copolymer having a weight average molecular weight of 10,000 or less. A polymeric optical material characterized in that 2. A core part made of a polymer material and a clad part made of a polymer material surrounding the core part and having a lower refractive index than the core part, wherein the core part and the clad part are
An optical waveguide, which is a polymer optical material obtained by thermally crosslinking the polymer optical material according to claim 1. 3. An optical waveguide in which an optical waveguide having a core part made of a polymer material and a clad part surrounding the core part and made of a polymer material having a refractive index lower than that of the core part is produced by laminating polymer materials. A method for producing an optical waveguide, which comprises a step of forming a core layer and a clad layer by applying the polymer optical material according to claim 1 and then thermally crosslinking the same.