JPH08304637A - Optical transmission body - Google Patents

Abstract

PURPOSE: To directly connect optical transmission bodies without using a device for signal conversion by using a noncrystalline fluorine-contg. polymer matrix having no C-H bonds to obtain an optical transmission body such as an refractive index distribution type optical fiber and then directly connecting the obtd. body to another optical transmission body. CONSTITUTION: A refractive index distribution type optical transmission body having a noncrystalline fluorine-contg. polymer (fluorine-contg. polymer (a)) matrix which does not substantially contain C-H bonds is directly connected to another optical transmission body through no device. This refractive index distribution type optical transmission body is produced by distributing a material (b) which gives the distribution of refractive index in the fluorine-contg. polymer (a) matrix. The material (b) is such a material that its refractive index is different by >=0.001 from that of the fluorine-contg. polymer (a), and it may have a higher or lower refractive index. Usually, a material having a higher refractive index is used for an optical fiber. The other optical transmission body except for the first optical transmission body is, for example, a quartz optical fiber such as a quartz single mode optical fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for optical / electrical signal conversion and electrical / optical signal conversion of a gradient index optical transmission medium and other optical transmission mediums such as a quartz single mode optical fiber. The present invention relates to an optical transmission body that is directly connected without intervening and without losing low transmission loss and high transmission bandwidth.

[0002]

2. Description of the Related Art In recent years, data communication using optical fibers has been actively proposed. A quartz single mode optical fiber is used for a long-distance trunk line system because of its low transmission loss and high transmission bandwidth. On the other hand, FTTH (Fiber T
For short distances (such as o The Home), the optical signal from the quartz single-mode optical fiber is once converted into an optical / electrical signal, and then the electrical / optical signal is converted again, and then a plastic optical fiber such as polymethylmethacrylate is used. It is proposed to transmit.

On the other hand, as a conventionally known plastic optical fiber, an optical resin represented by polymethylmethacrylate is proposed. As a graded-index plastic optical fiber consisting of a core and a clad as an optical fiber, many proposals have been made to use an optical resin such as polymethylmethacrylate, polystyrene, polycarbonate, polynorbornene for the core and a fluorine-containing polymer for the clad. . In addition, Japanese Patent Laid-Open No. 2-24
Japanese Patent No. 4007 also proposes using a fluorine-containing resin for the core and the clad.

Also known are graded index (GI) type optical fibers as well as graded index optical fibers. The refractive index distribution of a gradient index optical fiber is one in which the refractive index decreases from the center in the radial direction in a curve close to a parabola, for example, “Chemicals and Industry” Vol. 45, No. 7 (1992) 1261. -1264, JP-A-5-1730
26, WO94 / 04949, WO94 / 150
05 etc.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a heat resistance required for automobiles, OA (office automation), home electric appliances, etc., which cannot be reached by polymethylmethacrylate-based, polystyrene-based, polycarbonate-based optical transmission materials. Of visible light (500-500), which has properties such as resistance, humidity resistance, chemical resistance, and incombustibility, and which cannot be achieved by acrylic, polycarbonate, norbornene-based optical transmission materials.
700 nm) and near-infrared light (700-1600 nm) can be used, and further has low optical transmission loss and high transmission band in a wide transmission region band, and as a result, 1300 nm, 1550 used in quartz single mode optical fiber.
The wavelength such as nm is directly converted to optical / electrical signal, electricity /
It is an object of the present invention to provide an optical transmission body using a plastic optical transmission body which can be directly connected to another optical transmission body without the need for optical signal conversion.

[0006]

Means for Solving the Problems As a result of intensive studies based on the recognition of the above problems, the present inventor has imparted heat resistance, moisture resistance, chemical resistance and nonflammability, and has a near infrared light. In order to eliminate the C—H bond (that is, carbon-hydrogen bond) in which light absorption occurs, a fluoropolymer in which the C—H bond is converted to a C—F bond (that is, carbon-fluorine bond) is optimal. I got the knowledge that there is.

Further, in the case of the graded index type optical fiber, multimode light propagates while being reflected at the interface between the core and the clad, so that mode dispersion occurs and the transmission band is lowered. However, in the graded index optical fiber, mode dispersion hardly occurs and the transmission band increases. Therefore, by using a matrix of a non-crystalline fluorine-containing polymer having substantially no C-H bond as an optical transmission medium such as a refractive index distribution type optical fiber, and directly connecting these to another optical transmission medium. Have found that the above problems can be solved.

That is, the present invention is the following (1) to (7).

(1) A gradient index optical transmission medium having a matrix of a non-crystalline fluorine-containing polymer having substantially no C—H bond and another optical transmission medium are connected without a device. Optical transmitter.

(2) The optical transmission member according to (1), wherein the other optical transmission member is a quartz optical fiber or a quartz optical component.

(3) The optical transmission body according to (1), wherein the other optical transmission body is one or more selected from an optical branching / coupling device, an optical demultiplexer, an optical multiplexer, and an optical switch.

(4) The optical transmission article according to (1) above, wherein the non-crystalline fluoropolymer is a fluoropolymer having a ring structure in its main chain.

(5) The optical transmission article according to the above (2), wherein the fluoropolymer having a ring structure in the main chain has a repeating unit selected from the following (I) to (IV).

[0014]

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[In the above formulas (I) to (IV), 1 is 0 to 5, m is 0 to 4, n is 0 to 1, and l + m + n is 1 to 1.
6, o, p and q are 0 to 5, respectively, and o + p + q is 1 to
6, R ³ and R ⁴ are F or CF ₃ , R ⁵ is F or CF ₃ ,
R ⁶ is F or CF ₃ , X ¹ is F or Cl, and X ² is F or Cl. (6) The wavelength range of the transmitted optical signal is 200 to 1600
The optical transmission body according to (1), which has an arbitrary wavelength selected from nm.

(7) The optical transmission article according to (1), wherein the gradient index plastic optical fiber and the quartz single mode optical fiber are directly connected via a connector.

The optical transmission body referred to in the present invention is mainly composed of an optical fiber or a bundle fiber for transmitting an optical signal, or a combination of these with an optical signal, demultiplexing, multiplexing, switching, modulation, optical- Electric conversion, electricity-
A device that is connected to a device that performs optical conversion. Specifically, quartz single mode optical fiber strands, optical fiber cords, quartz optical fibers such as bundle fibers, or plastic optical fiber strands, optical fiber cords, bundle fibers, optical fiber cables, plastic fibers such as multi-core tape core wires, optical waveguides. And so on. Examples of the equipment include optical branching devices, couplers, optical multiplexers, optical branching devices such as optical demultiplexers, optical switches, optical attenuators, optical isolators, polarizers, optical integrated circuits, optical transmitter modules, and optical receiver modules. And so on.

Further, the device in the present invention means that, when an optical signal is transmitted from one optical transmission body to the other optical transmission body, the optical signal output from one side is once converted into an electric signal and then again. A device that converts light. If such a device is used, the circuit becomes complicated,
In addition to the transmission loss, it takes a lot of time and effort to make a connection, resulting in a high cost.

The gradient index optical transmitter according to the present invention comprises:
Since the matrix is an amorphous resin, it does not scatter light and has high transparency in a wide wavelength band from visible light to near-infrared light, so that it can be effectively used for optical transmitters of various wavelengths. 1300n, which is the wavelength used for trunk quartz single-mode optical fiber especially in the communication field
An optical transmission medium having low loss at m and 1550 nm is provided.
Therefore, in this optical transmission body, the fibers can be connected to each other directly or through a connector without the need for a quartz single mode optical fiber and a device for optical / electrical signal conversion and electric / optical signal conversion. Furthermore, since it is possible to prevent light leakage during bending and suppress loss, it can be used for optical transmission in fine parts such as wiring in OA equipment, or in automobiles and aircraft.

An optical transmission medium other than the refractive index distribution type optical transmission medium connected to this refractive index distribution type optical transmission medium without a device requires a conventional device among the above-mentioned optical transmission mediums. It was what I had. In particular, it is a quartz optical fiber such as a quartz single mode optical fiber.

The gradient index optical transmitter according to the present invention comprises:
A substance giving a distribution of refractive index to a non-crystalline fluoropolymer (hereinafter referred to as fluoropolymer (a)) matrix having substantially no C—H bond (hereinafter referred to as substance (b))
Is obtained by distributing.

The fluoropolymer (a) in the present invention is not particularly limited as long as it is a non-crystalline fluoropolymer having no C--H bond, but it is a fluoropolymer having a ring structure in the main chain. Is preferred. As the fluorine-containing polymer having a ring structure in the main chain, a fluorine-containing polymer having a fluorine-containing aliphatic ring structure, a fluorine-containing imide ring structure, a fluorine-containing triazine ring structure or a fluorine-containing aromatic ring structure is preferable. Among the fluoropolymers having a fluorinated aliphatic ring structure, those having a fluorinated aliphatic ether ring structure are more preferable.
As the fluorinated polymer (a), a fluorinated polymer having a fluorinated polyimide ring structure and a fluorinated polymer having a fluorinated alicyclic structure are preferable, and the latter is particularly preferable.

The fluorine-containing polymer having a fluorine-containing alicyclic structure is compared with the fluorine-containing polymer having a fluorine-containing imide ring structure, a fluorine-containing triazine ring structure or a fluorine-containing aromatic ring structure, which will be described later in the heat drawing or melting. It is a more preferable polymer because it is difficult for the polymer molecules to be oriented even when it is made into fibers by spinning, and as a result, light is not scattered.

The viscosity of the fluorinated polymer (a) in the molten state is 10 ³ to 200 at a melting temperature of 200 ° C. to 300 ° C.
10 ⁵ poise is preferred. If the melt viscosity is too high, not only melt spinning is difficult, but also necessary for forming the refractive index distribution,
Diffusion of the substance (b) is less likely to occur, making it difficult to form a refractive index distribution. In addition, if the melt viscosity is too low, there will be a practical problem. That is, when it is used as an optical transmitter in electronic devices, automobiles, etc., it is exposed to high temperatures and softens, and the optical transmission performance deteriorates.

The number average molecular weight of the fluoropolymer (a) is
It is preferably 10,000 to 5,000,000, more preferably 50,000 to 1,000,000. If the molecular weight is too small, heat resistance may be impaired, and if it is too large, it becomes difficult to form an optical transmission medium having a refractive index distribution, which is not preferable.

The polymer having a fluorinated alicyclic structure is obtained by polymerizing a monomer having a fluorinated ring structure, or a fluorinated monomer having at least two polymerizable double bonds is subjected to cyclopolymerization. A polymer having a fluorinated alicyclic structure in the main chain obtained as described above is suitable.

A polymer having a fluorinated alicyclic structure in its main chain, which is obtained by polymerizing a monomer having a fluorinated alicyclic structure, is known from Japanese Patent Publication No. 63-18964. That is, perfluoro (2,2-dimethyl-
1,3-dioxole) and other monomers having a fluorine-containing alicyclic structure are homopolymerized, and this monomer is also radical-polymerizable monomer such as tetrafluoroethylene, chlorotrifluoroethylene, and perfluoro (methyl vinyl ether). A polymer having a fluorinated alicyclic structure in its main chain can be obtained by copolymerizing with. Examples of repeating units of such a polymer are shown in (IV) above.

Further, a polymer having a fluorinated alicyclic structure in its main chain obtained by cyclopolymerization of a fluorinated monomer having at least two polymerizable double bonds is disclosed in JP-A-63-
It is known from JP-A-238111 and JP-A-63-238115. That is, perfluoro (allyl vinyl ether), perfluoro (butenyl vinyl _{ether), CF 2 = CF-CF} 2 -CFCl-CF 2 -CF =
By cyclopolymerizing a monomer such as CF ₂ or by copolymerizing such a monomer with a radical polymerizable monomer such as tetrafluoroethylene, chlorotrifluoroethylene, perfluoro (methyl vinyl ether), the main chain is formed. A polymer having a fluorinated alicyclic structure is obtained. Examples of repeating units of such a polymer are shown in the above (I) to (III).

Further, perfluoro (2,2-dimethyl-
Monomers having a fluorinated alicyclic structure such as 1,3-dioxole) and perfluoro (allyl vinyl ether)
A polymer having a fluorinated alicyclic structure in its main chain can also be obtained by copolymerizing a fluorinated monomer having at least two polymerizable double bonds such as or perfluoro (butenyl vinyl ether).

The polymer having a fluorinated alicyclic structure is
A polymer having a ring structure in the main chain is suitable, but a polymer containing 20 mol% or more, preferably 40 mol% or more of polymerized units having a ring structure is preferable in terms of transparency, mechanical properties and the like.

The method for producing the fluorine-containing polyimide is not particularly limited. For example, perfluoropyromellitic anhydride, an aromatic tetracarboxylic anhydride in which all hydrogen atoms are replaced by fluorine atoms, and perfluoro p, p '. A polyamic acid is produced by a reaction of an aromatic diamine in which all hydrogen atoms such as diaminodiphenyl ether are substituted with fluorine atoms, and this is further heated to give a fluorine-containing polyimide.

Specific examples of the fluorine-containing polyimide include those having a repeating unit selected from the following formula (V). The fluorine atoms in these fluoropolymers (a) may be partially substituted with chlorine atoms in order to increase the refractive index.

[0033]

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[In the above formula (V), R ¹ is

[0035]

[Chemical 4]

R ² is selected from

[0037]

Embedded image

Selected from: Here, R _f is selected from a fluorine atom, a perfluoroalkyl group, a perfluoroaryl group, a perfluoroalkoxy group, and a perfluorophenoxy group, and these may be the same or different. Y is

[0039]

[Chemical 6]

Selected from: Here, _R'f is selected from a perfluoroalkylene group and a perfluoroarylene group, and these may be the same or different.
r is 1-10. Further, Y and two R _f's may sandwich a carbon to form a ring, in which case the ring may be a saturated ring or an unsaturated ring. The polymer having a fluorinated alicyclic structure is preferably a polymer having a ring structure in its main chain, but a polymer containing 20 mol% or more, preferably 40 mol% or more of polymer units having a ring structure is preferable. It is preferable in terms of transparency and mechanical properties.

The substance (b) is at least one substance having a difference in refractive index of 0.001 or more in comparison with the fluoropolymer (a), and has a higher refractive index than the fluoropolymer (a). It may have a refractive index or a low refractive index. In optical fibers and the like, a substance having a higher refractive index than the fluoropolymer (a) is usually used.

The substance (b) is preferably a low molecular weight compound, an oligomer or a polymer containing an aromatic ring such as a benzene ring, a halogen atom such as chlorine, bromine or iodine, and a bonding group such as an ether bond. Further, the substance (b) is preferably a substance which does not substantially have a C—H bond for the same reason as the fluoropolymer (a). The difference in refractive index with the fluoropolymer (a) is preferably 0.005 or more.

The substance (b), which is an oligomer or a polymer, is a polymer of a monomer forming the above-mentioned fluoropolymer (a), and has a refractive index in comparison with the fluoropolymer (a). It may be an oligomer or a polymer having a difference of 0.001 or more. As a monomer,
It is selected from those which form a polymer having a difference in refractive index of 0.001 or more in comparison with the fluoropolymer (a). For example, two kinds of fluoropolymers (a) having different refractive indexes can be used, and one polymer (a) can be distributed as the substance (b) in the other polymer (a).

These substances (b) have a solubility parameter difference of 7 (cal) in comparison with the above matrix.
/ Cm ³ ) ^1/2 is preferable. Here, the solubility parameter is a characteristic value that is a measure of the mixing property between substances, and the solubility parameter is δ, the molecular cohesive energy of the substance is E, and the molecular volume is V. The equation δ = (E / V) ¹ Expressed as ^{/ 2} .

Examples of the low molecular weight compound include halogenated aromatic hydrocarbons containing no hydrogen atoms bonded to carbon atoms, particularly halogenated aromatic hydrocarbons containing only fluorine atoms as halogen atoms, fluorine atoms and others. The halogenated aromatic hydrocarbon containing a halogen atom is preferable in terms of compatibility with the fluoropolymer (a). It is more preferable that these halogenated aromatic hydrocarbons do not have a functional group such as a carbonyl group or a cyano group.

Examples of such a halogenated aromatic hydrocarbon include those represented by the formula Φ _r -Z _b [Φ _r is a b-valent fluorinated aromatic ring residue in which all hydrogen atoms are replaced by fluorine atoms, and Z is fluorine. Or a halogen atom other than fluorine, -Rf, -CO
-Rf, -O-Rf, or -CN. However, Rf is a perfluoroalkyl group, a polyfluoroperhaloalkyl group, or a monovalent Φ _r . b is 0 or an integer of 1 or more. ] There is a compound represented by. The aromatic ring includes a benzene ring and a naphthalene ring. The perfluoroalkyl group or polyfluoroperhaloalkyl group which is Rf preferably has 5 or less carbon atoms. As a halogen atom other than fluorine, a chlorine atom or a bromine atom is preferable.

Specific compounds include, for example, 1,3-
Dibromotetrafluorobenzene, 1,4-dibromotetrafluorobenzene, 2-bromotetrafluorobenzotrifluoride, chloropentafluorobenzene,
Examples include bromopentafluorobenzene, iodopentafluorobenzene, decafluorobenzophenone, perfluoroacetophenone, perfluorobiphenyl, chloroheptafluoronaphthalene, and bromoheptafluoronaphthalene.

As the substance (b) which is a polymer or an oligomer, among the substances having the repeating units (I) to (V), a fluorine-containing polymer having a refractive index different from that of the fluoropolymer (a) to be combined is used. Combined (for example, a combination of a fluoropolymer containing only fluorine atoms as halogen atoms and a fluoropolymer containing fluorine atoms and chlorine atoms, obtained by polymerizing two or more monomers of different types and different ratios) Combinations of different fluoropolymers) are preferred.

In addition to the fluorine-containing polymers having a ring structure in the main chain as described above, hydrogen atoms such as tetrafluoroethylene, chlorotrifluoroethylene, dichlorodifluoroethylene, hexafluoropropylene and perfluoroalkyl vinyl ether are not contained. Oligomers composed of monomers, copolymerized oligomers of two or more of those monomers, and the like can also be used as the substance (b). Also, -CF
₂ CF (CF ₃₎ O- or _{- (CF 2) n O- (} n is an integer of 1 to 3) such as perfluoropolyether having structural units of can be used. The molecular weight of these oligomers is selected from the range of molecular weight that makes them amorphous, and the number average molecular weight is 300 to
10,000 is preferred. Considering the ease of diffusion, a number average molecular weight of 300 to 5000 is more preferable.

The particularly preferred substance (b) is a chlorotrifluoroethylene oligomer because of its good compatibility with the fluoropolymer (a), especially the fluoropolymer having a ring structure in its main chain. Since the compatibility is good, the fluoropolymer (a), particularly the fluoropolymer having a ring structure in the main chain, and the chlorotrifluoroethylene oligomer are easily mixed by heating and melting at 200 to 300 ° C. be able to. Well, both can be mixed uniformly by dissolving in a fluorine-containing solvent and mixing and then removing the solvent. A preferred molecular weight of the chlorotrifluoroethylene oligomer is a number average molecular weight of 500 to 1
500.

The optical transmission medium of the present invention is most preferably a gradient index optical fiber.

In this optical fiber, the substance (b) is distributed in the fluoropolymer (a) with a concentration gradient from the center to the peripheral direction. Preferably substance (b)
Is a substance having a higher refractive index than the fluoropolymer (a),
The substance (b) is a core material in which the concentration is gradually reduced from the center of the optical fiber along the peripheral direction. In some cases, the substance (b) is a substance having a lower refractive index than the fluoropolymer (a), and this substance is distributed with a concentration gradient in which the concentration decreases from the periphery of the optical fiber toward the center. Fiber optics are also useful.
The former optical transmission body such as an optical fiber can be manufactured by arranging the substance (b) at the center and diffusing it toward the peripheral direction. The latter optical transmission body such as an optical fiber can be manufactured by diffusing the substance (b) from the periphery toward the center.

The optical transmission medium of the present invention has wavelengths of 700 to 1,6.
The transmission loss of 100 m at 00 nm can be 100 db or less. Particularly, in a fluoropolymer having an alicyclic structure in its main chain, the transmission loss at 100 m is 50 at the same wavelength.
It can be less than or equal to db. Wavelength 700-1,600
At relatively long wavelengths of nm, such low level transmission loss is extremely advantageous. That is,
Since the same wavelength as that of quartz optical fiber can be used, connection with quartz optical fiber is easy and the wavelength of 700 ~
Compared with the conventional plastic optical fiber that has to use a wavelength shorter than 1,600 nm, there is an advantage that an inexpensive light source can be used.

In the optical transmission article of the present invention, molding of the resin and formation of the refractive index distribution may be performed simultaneously or separately. For example, the optical transmission medium of the present invention can be manufactured by forming the refractive index distribution at the same time as forming the refractive index distribution by spinning or extrusion molding. Further, the refractive index distribution can be formed after molding the resin by spinning or extrusion molding.
Further, a preform (base material) having a refractive index distribution can be manufactured, and this preform can be molded (for example, spun) to manufacture an optical transmission body such as an optical fiber.

The optical fiber manufacturing method of the present invention includes, for example, the following methods (1) to (7). However, the method (1) is not limited to these and a particularly preferable method is (1).

(1) The fluoropolymer (a) is melted, and the fluoropolymer (a) containing the substance (b) or the substance (b) in the center of the melt of the fluoropolymer (a). And molding the compound (b) while diffusing the substance (b) or after diffusing the substance (b).

In this case, in order to inject the substance (b), not only the case of injecting the substance (b) in only one layer in the central portion,
The substance (b) may be injected in multiple layers in the central portion. The molding includes extrusion melt molding suitable for molding a rod-shaped base material such as an optical fiber preform, and melt spinning molding suitable for molding an optical fiber. (2) Fluorine-containing polymer (a) obtained by melt spinning or drawing
A method of repeatedly dip-coating a substance (b) or a fluoropolymer (a) containing the substance (b) on a core material made of

(3) A hollow glass tube made of a fluoropolymer (a) is formed by using a rotating glass tube or the like, and the substance (b) or the substance (b) is contained inside the polymer tube. A method in which the monomer phase forming the fluoropolymer (a) is sealed and polymerized while rotating at a low speed.

In the case of this interfacial gel copolymerization, in the polymerization process, the tube made of the fluoropolymer (a) swells in the monomer phase to form a gel phase, and the monomer molecules selectively diffuse into the gel phase. While being polymerized.

(4) By using two kinds of monomers which are a monomer forming the fluoropolymer (a) and a monomer forming the substance (b) and the reactivity of the monomers is different,
A method of advancing the polymerization reaction so that the composition ratio of the resulting fluoropolymer (a) and the substance (b) continuously changes from the peripheral portion toward the center.

(5) Fluorine-containing polymer (a) and substance (b)
Is mixed uniformly or in a solvent, and then the mixture obtained by volatilizing and removing only the solvent is made into a fiber by hot drawing or melt extrusion, and then (or immediately after being made into a fiber) in a heated state. A method of forming a refractive index profile by contacting with an active gas to volatilize the substance (b) from the surface. Alternatively, after forming the fiber, the fiber is immersed in a solvent that dissolves only the substance (b) without dissolving the fluoropolymer (a), and the substance (b) is eluted from the surface of the fiber to obtain a refractive index. How to form a distribution.

(6) The rod or fiber made of the fluoropolymer (a) is coated with only the substance (b) having a smaller refractive index than the fluoropolymer (a), or the fluoropolymer (a) ) And the substance (b) are coated, and then the substance (b) is diffused by heating to form a refractive index profile.

(7) The high-refractive-index polymer and the low-refractive-index polymer are melted by heating or mixed in a solution containing a solvent, and while multi-layer extrusion is performed (or after extrusion) under different mixing ratios. A method in which both are diffused to obtain a fiber with a final refractive index distribution. In this case, the high refractive index polymer may be the fluoropolymer (a) and the low refractive index polymer may be the substance (b), the high refractive index polymer may be the substance (b) and the low refractive index polymer may be the substance (b). ) Is okay.

The optical transmission medium of the present invention may be provided with a protective coating layer. The polymer constituting the coating layer is composed of a polymer other than the fluoropolymer (a) of the matrix. The type of polymer constituting this coating layer is not particularly limited, and at least one selected from those used for coating conventional inorganic or plastic optical fiber strands, or at least one of the fluoropolymers listed below can be used. Can be used. For example, as the non-fluorine-based polymer, low-density polyethylene, ethylene-vinyl acetate copolymer, (water) crosslinked polyolefin, polyolefin-based polymer such as polyolefin elastomer, polyester-based polymer such as polyethylene terephthalate, soft vinyl chloride resin Such as vinyl-based resin, polyvinyl-based or other vinyl-based polymer, dimethylpolysiloxane polymer, polyfluoroalkylmethylpolysiloxane polymer or other silicone-based polymer,
Polyamide, (foamed) polystyrene, polycarbonate, polyetherimide, polyphenylene oxide,
Examples thereof include polysulfone, poly-4-methylpentene-1, polyamideimide and the like. As the fluoropolymer,
Fluorine-containing rubber, trifluoroethylene polymer, chlorotrifluoroethylene polymer, tetrafluoroethylene polymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-ethylene- (perfluoroalkyl) ethylene copolymer, tetrafluoro The following (VI) of ethylene-perfluoro (alkyl vinyl ether) copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride polymer, vinylidene fluoride-hexafluoropropylene copolymer, etc.
Examples thereof include a fluoropolymer having a repeating unit selected from (X).

[0065]

[Chemical 7]

In addition to the above polymer coating, a curable resin such as an ultraviolet curable resin, an electron beam curable resin or a thermosetting resin may be coated on the optical fiber and cured to form a coating layer. it can. When an ultraviolet curable resin or an electron beam curable resin is used, there is an advantage that the optical fiber element wire is less damaged because the coating can be performed at a relatively low temperature. Examples of ultraviolet curable resins and electron beam curable resins include curable resins such as urethane acrylate-based, epoxy acrylate-based, silicon acrylate-based, polyester acrylate-based, polybutadiene acrylate-based, and polyfluoroalkyl acrylate-based resins. When these curable resins are used, a method of applying a liquid resin having an appropriate viscosity to the surface of the gradient index optical fiber and then curing the resin is applied. On the other hand, when polyamide or polyimide resin is used, the tensile strength of the fiber cord is increased and the mechanical durability is dramatically improved.

If desired, a plasticizer, a pigment, a cross-linking agent, an adhesive or the like can be added to the above-mentioned polymer constituting the coating material.

The production of the optical fiber cord having the coating layer is not particularly limited. For example, the intended optical fiber cord can be obtained by forming a coating material on the outside of the optical fiber manufactured by the above-mentioned method by extrusion coating or solvent coating method. Further, in the present invention, after coating each optical fiber to form a cord, a plurality of bundles can be bundled into a bundle fiber. The bundle fiber includes a multi-core tape core wire formed by arranging cords in parallel. It is also possible to make a cable by coating the optical fiber with a plastic or metal reinforced with aromatic polyamide, glass or carbon fiber. The gap inside the cable may be filled with thread, string, paper, plastic, various cushioning materials, grooved spacers, or the like.

The optical transmission medium of the present invention is a subscriber line communication line,
LAN in public facilities such as LAN in factories, LAN in hospitals, LAN in schools, floor cables, power line monitoring communication lines, automotive applications, monitor image transmission of train operating conditions, communication in large vessels on the open sea route, Data transmission in the aircraft,
High-speed, high-bandwidth video transmission, high-quality video, such as amusement machines such as arcade game machines,
It can be used in various fields such as transmission of stereoscopic images, wiring in devices such as computers and automatic exchanges, general indoor communication networks, various sensor fields, lighting, illumination fields, energy transfer and the like.

[0070]

EXAMPLES Next, examples of the present invention will be described more specifically, but it goes without saying that the description does not limit the present invention.

Synthesis Example 1 30 g of perfluoro (butenyl vinyl ether), 120 g of ion-exchanged water, 4.8 g of methanol and 76 mg of ((CH ₃ ) ₂ CHOCOO) ₂ as a polymerization initiator were used, and the internal volume was 200 ml.
It was placed in a pressure-resistant glass autoclave. After purging the system with nitrogen three times, suspension polymerization was carried out at 40 ° C. for 22 hours.
After the obtained polymer was isolated, it was heat-treated at 300 ° C. and washed with water.
As a result, a colorless and transparent polymer (hereinafter referred to as polymer A)
Was obtained. The intrinsic viscosity [η] of this polymer A was 0.34 at 30 ° C. in perfluoro (2-butyltetrahydrofuran). The glass transition point of the polymer was 108 ° C., and the refractive index was 1.34.

Synthesis Example 2 Perfluoro (butenyl vinyl ether) 2 g, perfluoro (2,2-dimethyl-1,3-dioxole) 8
g, perfluoro (2-butyltetrahydrofuran) 1
0 g, 20 mg of ((CH ₃ ) ₂ CHOCOO) ₂ as a polymerization initiator
Was placed in a pressure-resistant glass ampoule having an internal volume of 50 ml.
After purging the system with nitrogen three times, polymerization was carried out at 30 ° C. for 20 hours. As a result, 7 g of a transparent polymer (hereinafter referred to as polymer B) was obtained. The glass transition temperature of this polymer B is 21.
The refractive index was 0.degree. C. and 1.29.

Example 1 The polymer A obtained in Synthesis Example 1 above was dissolved in a solvent of perfluoro (2-butyltetrahydrofuran), and a chlorotrifluoroethylene oligomer (Difloyl # 20) having a refractive index of 1.42 was dissolved in this. (Manufactured by Daikin) was added in an amount of 15% by weight to obtain a mixed solution. This solution was desolvated to obtain a transparent mixed polymer (hereinafter referred to as mixed polymer C) C. The polymer A was melted and melt-spun by two-color extrusion at 300 ° C. while pouring the mixed polymer C of the melt into the center, whereby the refractive index at the center was 1.36 and 1.
An optical fiber was obtained that had a parabolic gradual drop to a refractive index of 34. Immediately after melt spinning, an optical fiber D (hereinafter referred to as an optical fiber D) was obtained by coating a silicone resin and further coating a vinyl chloride resin on the outside. The diameter of the core of the obtained optical fiber D is 125 μm, and the diameter of the silicone resin part is 4 μm.
The outer diameter of the vinyl chloride resin was 00 μm and 1 μm. Furthermore, the connector obtained by injection molding was attached. The optical transmission loss of the obtained optical fiber code D was 300 dB / km at 780 nm and 130 dB / km at 1550 nm, and it was confirmed that the optical fiber can well transmit light up to near infrared light.

Example 2 An optical fiber cord D having a length of 100 m and a quartz single mode optical fiber having a length of 1 km were connected by a connector, and then a transmission experiment of light from the quartz single mode optical fiber side to the optical fiber was conducted. Optical transmission loss is 1550
It was 15 dB / 100 m in nm, and as a result of measuring the baseband frequency characteristic, the transmission band was calculated to be 2.5 GHz.

Comparative Example 1 A commercially available polymethylmethacrylate-based plastic optical fiber E having a length of 100 m and a length of 1 k manufactured by Nippon Petrochemical Co., Ltd.
m quartz single-mode optical fiber was connected, and the same light transmission experiment as in Example 2 was performed. Due to the absorption loss of polymethylmethacrylate, the emitted light from the optical fiber could not be observed at 1550 nm.

Example 3 These two polymers were mixed in such a manner that a polymer A having a refractive index of 1.34 to be a core is on the inside and a polymer B having a refractive index of 1.29 to be a clad is on the outside. Melt spinning by color extrusion was performed. Immediately after spinning, coating was performed in the same manner as in Example 1, a connector was attached, and an optical fiber F (hereinafter,
Optical fiber F) was obtained. The optical transmission loss of the obtained optical fiber F is 300 dB / km at 780 nm, 1
It was 130 dB / km at 550 nm, and it was confirmed to be an optical fiber capable of favorably transmitting light up to near infrared light.

Comparative Example 2 A 100 m long optical fiber F and a 1 km long quartz single mode optical fiber were connected, and the same optical transmission experiment as in Example 2 was conducted. Optical transmission loss is 15 at 1550 nm
Although it was as good as 0 dB / km, as a result of measuring the baseband frequency characteristic, it was confirmed that the transmission band was calculated to be 25 MHz, which was 1/100 of that of the first embodiment.

[0078]

EFFECTS OF THE INVENTION By using a gradient index optical transmission medium, it is possible to directly connect with a quartz single mode optical fiber or the like without a device for optical / electrical signal conversion and electrical / optical signal conversion. It has become possible to transmit light from light to near infrared light with extremely low loss and high bandwidth. In particular, the optical transmission part made up of this gradient index optical fiber is ideal for short-distance optical communication because it is flexible and easy to branch and connect despite its large fiber diameter, and it causes optical transmission loss due to bending. Since it is small, it has heat resistance, chemical resistance, moisture resistance, and nonflammability that can be used for wiring of OA equipment and the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 29/10 LGZ C08L 29/10 LGZ C09D 127/12 PFG C09D 127/12 PFG G02B 6/18 G02B 6/18 // C08F 16/32 MKZ C08F 16/32 MKZ MLA MLA (72) Inventor Haruhisa Miyake 1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa Asahi Glass Co., Ltd. Central Research Laboratory

Claims (6)

[Claims] 1. A gradient index optical transmission medium having a matrix of a non-crystalline fluorine-containing polymer having substantially no C—H bond and another optical transmission medium connected to each other without interposing a device. Optical transmitter. 2. The optical transmission medium according to claim 1, wherein the other optical transmission medium is a quartz optical fiber or a quartz optical component. 3. The optical transmission medium according to claim 1, wherein the non-crystalline fluoropolymer is a fluoropolymer having a ring structure in its main chain. 4. The optical transmission medium according to claim 2, wherein the fluoropolymer having a ring structure in the main chain has repeating units selected from the following (I) to (IV). Embedded image [In the above formulas (I) to (IV), 1 is 0 to 5, m is 0 to 4, n is 0 to 1, l + m + n is 1 to 6, o, p, q
Is 0 to 5, o + p + q is 1 to 6, R ³ and R ⁴ are F, respectively.
Or CF ₃ , R ⁵ is F or CF ₃ , and R ⁶ is F or CF
₃ , X ¹ is F or Cl, and X ² is F or Cl. ] 5. The wavelength range of the transmitted optical signal is from 200 to
An arbitrary wavelength selected from 1600 nm.
The optical transmission body described. 6. The optical transmission article according to claim 1, wherein the gradient index plastic optical fiber and the quartz single mode optical fiber are directly connected via a connector.