MXPA00007340A - Optical fiber connector using photocurable adhesive - Google Patents

Abstract

A fiber optic connector including a holder for one or more optical cables, each optical cable having an optical fiber surrounded by strengthening fibers, both of which are surrounded by at least one polymeric coating layer. The cable is stripped in a layerwise manner such that an area of exposed fiber is succeeded by an area of exposed strengthening fibers, succeeded by an area of coated cable. A visible light curable adhesive is injected into the holder and cured by exposure to visible light for up to 30 seconds, bonding the optical fiber layers and the holder into a unified structure.

Description

OPTICAL FIBER CONNECTOR USING PHOTOCURABLE ADHESIVE BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The invention relates to a fiber optic connector and the use of radiation in the visible portion of the spectrum to cure a photocurable adhesive in a fiber optic connector to join the optical fiber, the reinforcing fibers and the optical carrier in a unified structure, in order to provide an improved connection between two optical fibers or an optical fiber of an optoelectronic component.

DESCRIPTION OF THE PREVIOUS TECHNIQUE Optical fibers have replaced copper wire as the preferred means of transporting telecommunication signals. As with copper wire, it is necessary to provide the interconnection of optical fibers during the installation, repair or replacement of the fibers, and to terminate the fibers in the active optical devices. In general, there are two kinds of interconnection devices, the splices and REF .: 12170 the connectors. The term "splice" usually refers to a device, which provides a permanent connection between a pair of optical fibers. The term "connector", in contrast, usually refers to a device, which can be coupled and uncoupled repeatedly, often with a different plug or receptacle. A connector may also refer to the plug portion of a fiber termination, which is attached to an optical device. Optical devices include, for example, optical sensors (photoelectric diodes) and light sources (LED, laser diodes). The termination of an optical fiber can be indirect, that is, the fiber can be connected to some other optical device (passive) such as a beam splitter or polarizer, before the light beam is directed to the active optical device. The present invention is generally directed to a connector, although this term should not be considered in the limiting sense since the present invention can inherently provide a permanent, as well as temporary, connection or termination. In the fiber optic connector described in U.S. Patent No. 5,381,498, - "-" "" • * - the connector has a plug of a receptacle, the plug having a V-shaped slot, receiving the fiber for each fiber to be interconnected, with the end of the fiber ending at the midpoint of the slot. The receptacle has a plate that retracts as the plug is inserted, whereby the other fiber is lowered into the V-groove of the plug. Upon complete insertion of the plug, the two fiber ends are in contact, and the fiber secured to the receptacle is elastically deformed to maintain a compressive, continuous load between the terminal ends of the fibers. The connector provides a rapid disconnection and reconnection of a plurality of pairs of optical fibers, without the use of clamps or other alignment members. High strength fibers can be used to resist the repeated insertions and bends of the fibers. The exact lengths of the fibers (ie, the relative locations of their terminal ends in the plug and receptacle) are not critical since a tolerance is provided for the assumed clearance in the fiber of the bent receptacle (the terminal portion of the fiber secured). the plug does not bend, but always remains straight). The ends of the fibers can be prepared simply by cutting and beveling; the end surfaces can optionally be cut at an angle (ie, not orthogonal to the fiber axis) to reduce reflections of the signal. Many fiber optic splices employ plate elements having fiber reception slots, with mechanisms for holding the terminal ends of the fibers in a common slot. Some of these devices are designed to interconnect a plurality of fiber pairs, such as the splice shown in U.S. Patent No. 5.151,964. In U.S. Patent No. 4,028,162, the fibers approach the aligning grooves at an oblique angle and are temporarily held while a connecting plate is adhered to the interconnected fibers. For other examples of techniques comprising curved fibers entering the alignment slots, see U.S. Patent Nos. 4,077,702, 4, 148, -559, 4,322,127 and 5,080,461, and French Patent Application No. 2,660,442. Some of the connector designs that use the principle of bending a fiber in a slot Fiber alignment are rather complex and require many parts, such as the designs seen in U.S. Patent Nos. 4,045,121, 4,218,113 and 4,767,180. In order to provide a termination or interconnection with the required strength without damaging the system, the fibers must be secured to the body of the connector to inhibit or at least reduce the relative movement between the optical fiber and its outer sleeve. This joining system can be mechanical, such as a clamp or a set of clamps or it can be a type of adhesive. Also a mechanical system may include resistance members such as layers of braided steel wire, as described in U.S. Patent No. 5,539,849. The adhesives useful for the termination may be capable of bonding to the outer surface of the fiber, which may be formed from materials such as glass, epoxy silicones and the like. It must also be able to join other materials used in fiber optic cables and their terminations, such as polymeric coating layers, and reinforcing fibers used for surround the optical fibers, and plastics from which the cutter is formed. The reinforcing fibers are typically aromatic polyamide fibers derived from p-phenylenediamine and terephthaloyl chloride, commercially available as Nomex® or Kevlar®. U.S. Patent No. 4,699,462 describes a method for forming a termination between an optical fiber cable having a centrally placed optical fiber, a plurality of surrounding reinforcements, and a component housing. An adhesive, preferably a heat-activated adhesive, is applied within the termination and applied to a thermal shrink tubing in order to force the reinforcing fibers into adhesive bond with the adhesive layer. The bonded formation occurs mainly at the interface between the coating in the optical fiber core, and the reinforcing strands. The adhesive does not provide a connection to the thermal shrink tubing; is present to provide reinforcement to the termination. U.S. Patent No. 5,058,984 describes a fiber cable connector Optics comprising an outer plastic sleeve that is optically coupled to another fiber optic cable, carrying at one end, connection means for coupling, a tubular fastening member that adheres the fiber to the outer sleeve or carrier, which It is deformed by the application of forces to hold the end portion of the outer plastic sleeve and a bushing mounted within the other end of the connector body that supports an exposed terminal or end portion of an optical fiber. The optical fiber is adhered to the bushing with adhesive material. The bushing is made of ceramic material and the exposed end of the fiber is fixed with a curable resin with light, in general blue light where the bushing is formed of zirconium. This allows the setting or hardening time to be reduced to approximately 60 seconds. Specifically, it is disclosed that a curable adhesive with irradiation can not adhere sufficiently strongly to the outer plastic sleeve; therefore the adhesive material is used to secure the end portion or terminal inside the bushing, and need not provide any adhesive to the outer plastic sleeve.

As can be seen, even with the use of adhesives, conventional assemblies of fiber optic connectors have required the use of an additional means of placement or joining in order to withstand the destructive force. It will be very desirable to remove these media and be able to provide a unified system where the bond is formed solely from an adhesive that adheres the optical fiber to the outer carrier of the connector, and adheres to the optical fiber as well as the coating and the fibers. reinforcing fibers without requiring an additional positioning means such as a thermal shrinkage pipe, fastening members and the like. United States Patent No. ,525,648 discloses a treatment method for the application for application to dentine and cervical enamel or adhesion to hard fabric in a high humidity environment. The sizing compositions described bind strongly to dentin, and exhibit high tear strength, and include an acid and a film former, which are applied and then hardened. A wide variety of acids are useful, including organic, inorganic, solid and liquid acids. The trainers of Useful films are water dispersible and can be selected from many polymers, monomers and mixtures. After the standing time to achieve the sizing, the sizing, optionally with an additional layer of film former then hardens by the use of a polymerization catalyst. U.S. Patent No. 5,545,676 discloses a ternary or three component photoinitiator system for use in the further polymerization. A variety of acrylic monomers are described. The system is described to provide a combination of curing speed, curing depth and shelf life and is described as being useful in color profiling systems, curable inks, printing plates, photoresist gums, coated abrasives, photocurable adhesives and compound products, for example, for dentistry or self-repair of the body. The present invention provides a fiber optic connector that uses a photocurable adhesive composition of visible light to bond the optical fiber (s), the reinforcing fibers surrounding the fiber and a coating layer. on it in a unified structure. The system provides a quick cure, good depth of cure, and a safe low energy means to provide the joint, which can be easily achieved by a merchant.

BRIEF DESCRIPTION OF THE INVENTION The invention provides a fiber optic connector comprising an optical fiber, and a termination or interconnection joined in place only by means of a photocurable adhesive with visible light. Specifically, the invention provides an optical fiber connector including: a) at least one fiber optic cable comprising at least one optical fiber surrounded by a plurality of reinforcing fibers, both of which are surrounded by at least one polymeric coating layer, a portion of the cable that is stripped in layers such that an area of the exposed fiber is produced "by an area of exposed reinforcing fibers, succeeded by a coated cable area, b) a carrier for the optical cable; and J c) a curable adhesive with visible light injected into the carrier, the optical fiber, the reinforcing fibers and the carrier which are joined in a structure unified by means of exposure to visible light for a period of up to 30 seconds. Preferably, the adhesive comprises at least one acrylate monomer. The adhesive can be cured by visible radiation having a wavelength between 400 and 700 nanometers; preferably from 400 to about 600 nanometers, a portion of the blue and green area of the spectrum is injected, preferably between 500 and 600 nanometers. The healing time is less than 30 seconds, preferably less than 25 seconds. The adhesive binds strongly to the fiber, the coating and the carrier to form a unified structure, such that the structure does not break easily when force is applied to the connector, or to the reinforcing fibers. In an alternative embodiment, the adhesive is a photocurable adhesive that can be cured by exposure to radiation having wavelengths from 700 nm to 1100 nm, in the near infrared region.

Preferred fiber connector assemblies of the invention comprise an adhesive having a ternary photoinitiator system comprising an electron donor, a sensitizer and a diaryliodonium salt. The invention also provides a method for joining interconnections or terminations in fiber optic connectors and cables where the termination or interconnection is attached in place only by means of a photocurable adhesive with visible light. As used in this, these terms have the following meanings. 1. The term "visible light" means electromagnetic radiation having wavelengths between 400 nm and 700 nm. 2. The term "near infrared" abbreviated "nIR" means electromagnetic radiation having wavelengths between 700 nm and 1000 nm. 3. The term "plug" means an article, which is present in a connector, for selectively retaining and aligning the first optical fiber in a connector. The plugs can be inserted into the receptacle to form a connection or termination. 4. The term "receptacle" means an article present in a connector, for selectively retaining and aligning the second optical fiber in a connection. 5. The term "carrier" means that portion of the plug that holds or carries the first optical fiber in place. 6. The term "connector" means an article for forcing the end of a first optical fiber toward one end of a second optical fiber in contact at the end of the first optical fiber. A connector includes a plug and receptacle. 7. The term "unified structure" as used herein refers to the condition wherein the components, including the optical fiber, the plurality of reinforcing fibers and the carrier are joined in a fixed, joined relationship held together by adhesive photocurable that has been exposed to actinic radiation of wavelength suitable for the polymerization of the adhesive. 8. The terms "termination" and "connection" mean the point at which a first optical fiber is forced into contact with either a second Optical fiber or a rote optical device oelect. 9. The term "(meth) acrylate" includes both acrylate and methacrylate. 10. The term "GGP" fiber refers to a glass fiber on a roof concentrically with successive layers of glass coating and polymeric layers, often epoxy silicone coating. As used herein, all parts, by hundreds, and ratios are by weight, unless otherwise stated in a specific manner.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood with reference to the accompanying drawings, wherein: Figure 1 is a side view of a longitudinal section of an embodiment of the present invention, depicting a fiber optic connector that includes a plug and a receptacle. Figure 2 is a perspective view of the plug and receptacle of Figure 1, with a partial section revealing the curved fibers inside the plug.

DETAILED DESCRIPTION OF THE INVENTION The optical fiber assemblies of the invention comprise at least one optical fiber in a carrier, adhered to the carrier by means of a photocurable adhesive. While prior systems using adhesives have required other positioning devices such as the thermally shrinkable tubing "clamping members" and the like, the assemblies of the invention develop a strong bond between the adhesive and the various portions of the connector such as the carrier, the coating of the fiber optic cable, the reinforcing members and the optical fiber, forming a unified structure. The adhesive systems useful in the assemblies of the invention are photocurable in the visible area of the spectrum, and can be applied as one or two part adhesives. The adhesives may be provided already in the fiber assembly, or may be provided separately, in syringe-type applicators, to allow application in the field. A wide variety of monomers can be photopolymerized to form the connection or termination in the connector of the invention. Suitable monomers contain at least one ethically unsaturated double bond, and are capable of undergoing further polymerization. The molecular weight may vary, and the monomers discussed may include oligomers. A preferred monomer is formed by combining a dimethacrylate derived from the reaction of methacrylic acid and diglycidyl ether of bisphenol a (BISGMA) with a hydrophilic monomer such as hydroxypropyl methacrylate, hydroxyethyl metacrylate, (HEMA), or methacrylic acid. These monomers include mono-, di-, or poly (meth) -acrylates such as methyl (meth) acrylic acid, (meth) acrylic or ethyl, (meth) acrylic acid, (meth) acrylic acid hexyl, (meth) stearate acrylate, (meth) acrylic acid, glycerol di (meth) acrylate, tri- (meth) glycerol acrylate, di (meth) acrylate, and i-glycol, d? - (met) dielectrolylic acid acrylate, di (meth) acrylate of trile glycolol, di (meth) acrylate of diet i liclicol, trimetacycloate of glycerol glycol, di (meth) acrylate of 1,3-propanediol, t ri ( methacrylamide, tri-methylolpropane acrylate, tri (meth) acrylate, 1,2,4-butane-poly, 1,4-cyclohexanediol diacrylate, tet pentaerythritol ramethacrylate, sorbitol hexa (meth) acrylate, bis-1- (2-acryloxy)] -p-et oxy phenyldimethyl-methane, bis [1- (3-acryloxy-2-hydrox?)] - p -propoxyphenyl? -dimethylmethane, trihydroxyethyl-isocyanurate tri (meth) acrylate, bis-acrylates and bis-methacrylates of polyethylene glycols having molecular weights between 200 and 500; copolymerizable mixtures of acrylate monomers such as those described in U.S. Patent No. 4,652,274 and acrylated oligomers such as those described in U.S. Patent No. 4,642,126, unsaturated amides such as methylen-bis-acrylamide , methylene-bismetacrylamide, 1,6-hexamethyl-bis-acrylamide, diethylenetriamine, t-acrylamide and methacrylate of beta-methacrylate, and vinyl compounds, such as styrene, diallyl phthalate, divinyl succinate. , divinyl adipate and dívinyl phthalate. The adhesive may contain only one type of monomer or mixtures of two or more monomers may be used. The photoinitiator system is one, which is capable of absorbing light in the visible range, ie, between 400 nm and 700 nm, or in the region near IR of 700 to 1100 nm. In the Preferred mutants of the invention, the photoinitiator absorbs light between 400 nm and 600 nm, more preferably between 500 nm and 600 nm, in the green and a portion of the blue portion of the spectrum. The components in the photoinitiator system include at least one initiator and at least one sensitizer. Useful sensitizers must be soluble in the monomer and be capable of absorbing light at the appropriate wavelengths. The sensitizer is also preferentially capable of sensitizing 2-methyl-4,5-bis (t-ricloromet-il) -s-triazine, according to the test procedure described in U.S. Patent No. 3,729,313. Preferably, the sensitizer is also stable on the shelf for reasonable periods of time. Suitable sensitizers are believed to include compounds in the following categories: ketones, coumarin dyes (e.g., keto-coumarins), xanthene dyes, acridine dyes, thiazole dyes, thiazine dyes, oxazine dyes, azine dyes , Aminoketone dyes, Forforins, Polycyclic aromatic hydrocarbons, Amines tiryl-ketone p-Substuuides compounds, J aminot ri aryl-methanes, merocyanines, escuiarilium dyes and pyridinium dyes. Ketones (for example, monoketones and alpha-diketones), ketocoumarins, aminoaryl ketones and p-substituted aminostyryl ketone compounds are the preferred sensitizers. For applications requiring high sensitivity it is preferred to employ a sensitizer containing a portion of j-ulolidinyl. For applications that require deep cure (eg, where the coating or reinforcing fibers attenuate radiation of similar wavelengths), it is preferred to employ sensitizers having an extinction coefficient below 1000, preferably below 100, at the desired wavelengths of irradiation for photopolymerization. By way of example, a preferred class of ketone sensitizers has the formula: ACO (X) bE where X is CO or CRZR2, where R1 and R2 may be the same or different, and may be hydrogen, alkyl, alkaryl or aralkyl, b is one or zero, and A and B may be the same or different and may be substituted (having one or more non-interfering substituents) or unsubstituted aryl, alkyl, alkaryl or aralkyl groups, or together A and B may form a cyclic structure which may be a fused aromatic ring or heteroaromatic, aromatic, cycloaliphatic, substituted or insubstated. Suitable ketones of the above formula include monoketones (b = 0) such as 2,2-, 4,4- or 2,4-dihydroxybenzophenone, di-2-pyridyl ketone, di-2-furanyl ketone, di-2-thiophenyl ketone, benzoin, fluoros, quinones, for example, chloroquinone, 2-aza-3-carboxy-9-fluorone, and the like, chalcone, Michler's ketone, 2-fluoro-9-fluorone, 2-chlorothioxanthone, acetophenone, benzophenone, 1- or 2-acetonaphthone, 9-acetylanthraceum, 2-, 3- or 9-acetyl-phenanthrene, 4-acetyl-biphenyl, propiophenone, n-butyrophenone, valerophenone, 2-, 3-or 4-acetyl-pyridine, 3-acet-ilcoumarin and the like. Suitable diketones include aralkyldicyketones such as ant raquinone, fenant renoquinone, o-, m- and p-diacetyl benzene, 1,3-, 1,4-, 1,5-, 1,6-, 1,7- and 1 , 8-, diacetylnaphthalene, 1,5-, 1,8- and 9,10-diacetylanthracene and the like. The a-diketones suitable (b = 1 and X = CO) include 2,3-butanedione, 2,3-pentanedione, 2,3-hexanedione, 3,4-hexanedione, 2,3-heptanedione, 3,4-heptanedione, 2, 3 -octanedione, 4, 5-octanedione, benzyl, 2,2'-, 3,3'- and 4,4'-dihydroxybenzyl, furyl, di-3, 3'-indolylenedione, 2,3-nanedonione (camphorquinone), 1,2-cyclohexanedione, 1,2-naphthaquinone, acenaphthaquinone and the like. Other preferred sensitizers include Rose Bengal, fluorescein, eosin yellow, eosin Y, ethyl eosin, bluish eosin, yellowish mixture of erythrosin, 4 ', 5'-dibromofluorescein. The photoinitiator system also includes an electron donor. A wide variety of donors can be used; The donor must be soluble in the monomer, and has good shelf or shelf stability. Suitable donors are capable of increasing the cure rate or depth of cure of a composition upon exposure to light of the desired wavelength. The donor has an oxidation potential greater than zero, and less than or equal to the oxidation potential of p-dimethoxybenzene. Preferably, the oxidation potential is between approximately 0. 5 and 1 volts against a saturated calomel electrode (S.C.E.). The values can be measured experimentally or obtained from references such as N.L. einburg, Ed., Tech in i of The Ectroorgani c Syn thes i s Pa rt II Techni ques of Chemi s try, Vol. V (1975) and the like. Preferred donors include amines (including aminoaldehydes and aminosilanes), amides (including phosphoramides), ethers (including thioethers), ureas (including thioureas), ferrocene, sulfinic acids and their salts, ferrocyanide salts, ascorbic acid and its salts, acid iocarbamic dith and its salts, salts of xanthates, salts of ethylene diamine tetraacetic acid, and salts of tetraphenylboronic acid. The donor may be unsubstituted or substituted with one or more non-interfering substituents. Particularly preferred donors contain an electron donating atom such as a nitrogen, oxygen, phosphorus or sulfur atom, and a removable hydrogen atom attached to a carbon or silicon atom to the electron donating atom. Preferred amine donor compounds include alkyl-, aryl-, alkaryl- and aralkyl-amines such as methylamine, ethylamine, propylamine, butylamine, tpetanolamia, amylamine, hexylamine, 2,4-dimethylanilm, 2,3-d-methylanilm, o-, m- and p-toluidine, benzylamine, aminopyridine, N, N'-imethylethylenediamma, N, N'-d? et? let? lend? am? na, N, N '-dibencylethylenediamine, N, N' -dietll- 1,3-propanediamma, N, N'-d? et? l-2-butene-l, 4-d ? am? na, N, N '-d? met? l-1, 6-hexanod? amma, piperazm, 4,4'-tpmethylenedipipepdine, 4,4' -ethylenedipiperidm, pN, N-dimethyl-ammofenetanol and pN- dimethylaminobenzonit rile; aminoaldehydes such as pN, N-dimethylammobenzaldehyde, pN, N-diethylamino-benzaldehyde, 9-j ulolidine-carboxaldehyde and 4-morpholinobenzaldehyde, and aminosilanes such as trimethylsilylmorpholine, tpmethylsilylpiperidine, bis (dimethylamino) diphenylsilane, tris- (dimethylamino) methylsilane , N, Nd? Et? Lma? No-tpmethylsilane, tris (dimethylamino) -phenyls, tris (methylsilyl) amine, tris- (dimethylsilyl) amine, bis (dimethylsilyl) amine, N, Nb? S (d? met? ls? l) -aniline, N-phenyl-N-dimethyllsilyl-aniline and N, N-dimethyl-N-dimesylsilylamine. Tertiary aromatic alkylamines, particularly those having at least one electron withdrawing group in the aromatic ring, have been found to provide shelf stability especially good Good shelf stability has also been obtained using amines that are solid at room temperature. Preferred amide donor compounds include N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-N-phenylacetamide, hexamethylphosphoramide, hexaethylphosphoramide, hexapropylphosphoramide, trimorpholinophosphine oxide and tripendinophosphide oxide. Suitable ether donor compounds include 4, 4'-dimethoxybiphenyl, 1,2,4-t-p-methoxybenzene and 1, 2, 4, 5-tetramethoxybenzene. Suitable urea donor compounds include N, N'-dimethylurea, N, N-dimethylurea, N, N'-diphenylurea, tetramethylthiurea, tet rathyltyurea, tetra-n-butyl thiourea, N, N-di-n- but ilt iourea, N, N'-di-n-butylthiourea, N, N-diphenylthiourea and N, N'-diphenyl- N, N'-diet ilt iourea. In one embodiment of the invention, the photoinitiator system is a ternary system, in accordance with U.S. Patent No. 5,545,676. In this three-component system, the additional component is a diaryl-iodonium or sulfonium salt. The salt must also be soluble in the monomer and be stable on shelf or shelf when dissolves therein in the presence of the sensitizer and donor. Accordingly, an election of a particular iodonium or sulfonium salt may depend to some degree on the selected monomers, and the other portions of the photoinitiator system. This ternary system must contain these three parts; however, it may contain more than one sensitizer or electron donor, if desired. Useful salts are those described in U.S. Patent Nos. 3,729,313, 3,741,769, 3,808,006, 4,250,053 and 4,394,403. Preferred preferred iodonium salts include di-phenyliodonium chloride, di-phenyliodonium hexafluorophosphate and diphenyliodonium tetrafluoroborate. The useful complex sulfonium salts are substituted with at least one, preferably three aromatic groups. Representative groups are aromatic groups having from 4 to 20 carbon atoms and are selected from phenyl, thienyl and furanyl groups. These aromatic groups may optionally have one or more benzo fused rings (for example, naphthyl and the like: benzothienyl, dibenzothienyl, I benzofuranyl, dibenzofuranyl, etc.). These aromatic groups may also be substituted, if desired, by one or more of the following groups, or by other groups which are essentially unreactive with other components present in the particular composition in which the complex salt is to be used: halogen , nitro, aryl, ester groups, sulphoester groups, amido groups, carbamyl groups, sulfamyl groups, alkoxy groups, aryl groups, alkyl groups, aryloxy groups, alkylsulfonyl groups, α-sulfonyl groups, perfluoroalkyl, and perfluoroalkylsulfonyl groups. Examples of suitable photoinitiators of the sulfonium aromatic complex salt include: triphenylsulfonium tetrafluoroborate, methyldiphenylsulfonium tetrafluoroborate, dimethylphenylsulfonium hexafluoroborate, dimethylsulfonium dimethyl hexafluorophosphate, hexafluoroantimonat or tpfei 1 sulphonium, tetrafluoroborate 4 -butoxyphenyl phenylsulfonium, 4-chlorophenyldiphenylsulfonium hexafluoroantimonate, t-ris (4-phenoxypheni-1) sulfonium hexafluorophosphate, di (4-ethoxyphenyl) methylsulfonium hexafluoroarsenate, tetrafluoroborate 4-Acetam? Dofen? Ld? Fe? Lsulfon? O, dimethylnaphthylsulfonium hexafluorophosphate, trifluoromethyldiphenylsulfonium tetraflaoroborate, methyl hexafluoroantimonate (N-met? Lfenot? Az? An? L) sulfonium, phenylmethylbenzylsulphonium hexafluorophosphate, 10-methyl hexafluorophosphate i 1 phenoxatinium, 5-methyl 1-tantrenium hexafluorophosphate, 10-phenyl-9,9-hexafluorophosphate, 10-phenyl-9-oxo-oxantenium tetrafluoroborate, 5-methyl hexafluorophosphate ? l-10-10-? oxot? antren? o. Preferred salts are the salts substituted with triaplo such as tri phenylsulfonium hexafluorophosphate. The substituted salts with tparyl are preferred because they are more technically stable than the dibust salts of mono- and di-diaryl and can therefore be used in curable systems of a part where a long shelf life is desired. Complex salts substituted with triaplo are also more treatable for dye sensitization according to this invention. The adhesive of the present invention can be used with a variety of different connector designs. Figures 1 and 2 illustrate a mode of an optical fiber connector according to the present invention. The connector 10 is comprised of an elongated plug 12 and a socket or receptacle 14. Figure 1 is a longitudinal section of the connector 10 showing the plug 12 fully inserted in the receptacle 14, the receptacle 14 mounted on a support surface or screen 16. Figure 2 is a perspective view with the screen 16 omitted, also with a longitudinal, partial section to illustrate the interior of the connector. The embodiment shown provides the interconnection of the two fiber pairs, but those skilled in the art will appreciate that the inventive concepts described herein extend to the interconnection of an individual pair as well as interconnections of a multiplicity of pairs. The plug 12 includes a fiber carrier 18 that can be constructed of two fastening elements or blocks 20 and 22 and a body or cover "24 plug that attaches to fiber carrier 18.

The optical fibers "30 and 32 to be interconnected or terminated, pass through the carrier 18 and into the hollow interior of the cover 24. The terminal portions of the fibers are bare, that is, they are not fixed to any alignment member such as a bushing. The cover 24 thus serves not only to assist in the physical location of the plug 12 in the receptacle 14, but also to provide protection for the end portions of the fibers otherwise exposed (the cover could be made retractable to fully expose the tips of the fibers if required). The carrier 18 has fiber receiving slots 34 formed on the adjacent surfaces of the blocks 20 and 22; These two components can be identical parts. The optical fibers are secured to the carrier 18 by the use of the adhesive described hitherto. The adhesive is injected through holes in the connector for that purpose, and cured. The adhesive will be added to the cable coating, which is typically epoxy silicone, polyolefin or polyvinylchloride, where it is still present as well as the reinforcing fibers, for example, KEVLARE, in those areas where the outer coating has been removed, towards a layer inner polymer, which is typically equal to epoxy silicone, polyolefin or polyvinylchloride, and finally to the fiber itself to retain the fiber in its position. The carrier 18 may have an extension 36 surrounding the fibers for tension release and additional restraint. A cover 38 can be provided for the release of additional tension and capture of the reinforcing fibers in the fiber cable (Kevlar strands "), and to assist in the management of the plug 12. The reinforcing fibers do not need to be trimmed, but they can be adhered to the unified structure of the average carrier of the same adhesive as used to secure the fiber to the carrier, as described above.The relief or release of tension of the reinforcing members is achieved by a force adjustment of the section. Straight wall of the fiber optic carrier within the cover 38. This is dependent on the choice of the materials used for the boot 38 and the fiber optic carrier 18, and produces a design that does not require a ripple ring and assists in the ease of manufacture and reduces the number of necessary components The "unidirectional" barbels on the surface of the fiber optic carrier help in attaching the cover 38 to the carrier 18 Optical bra, which also helps in the connection of the cable to the plug 12.

A latch 40 is integrally molded on one side of the cover 24 to releasably secure the plug 12 to the receptacle 14. The latch 40 can also impart mechanical polarization to the plug, i.e., it can be inserted into the receptacle 14 only in an orientation. The plug 12 can be deflected in the interconnected position, for example, by a trampoline (a flexible cantilever) formed within the receptacle 14, which is to be pushed against the latch 40 to minimize the effect of manufacturing tolerances. The receptacle 14 includes a body or housing 70 and another fiber carrier 72. The housing 70 may also have appropriate features (such as lock arms 76) that allow it to be removably mounted to the bulkhead 16 which may be, for example, a patch panel or an output from the workstation (plate the wall box). The lock mechanism can provide mounting from the front of the panel, to allow all preparatory work to be done on the front side of the panel, can provide mounting from the back of the panel, to allow all the preparatory work is done on the back side of the panel. Additional mechanisms, such as fastening the fiber, can be provided to retain the fibers firmly in the grooves. The fibers do not extend to most fingertips 82 and 84 but rather terminate at a sufficient distance from the tips to allow proper support of the portion of the optical fibers in the plug when the connector is in use. If fiber-to-fiber contact is present very close to the tips of the V-grooves (or if the plug is inserted too far), the portion of fiber in the plug can bend beyond the slot and rise from the apex, breaking the connection. The receptacle 14 can have both of these fingers with fiber alignment slots as there are fibers in the plug 12. The fingers 82 and 84 are formed to protrude towards the slots 54 and 56, respectively, of the cover 24 when the plug 12 insert completely into the receptacle 14. The fingers 82 and 84 enter the cover 24 at an oblique angle (not zero) with respect to the axis of the plug, i.e. the axis defined by any of the optical fibers 30 or 32 when they extend straight into the cover 24. This angle is preferably close to 42 °, which offsets the interests with respect to the contact pressure at the end surface of the fiber, the forces of the fibers directed in the V-groove , the friction effects, and the desired tolerance window (a greater angle increases the tolerances). Since the fibers of the receptacle are not directed towards the opening 74, there is no danger of leakage of light injuring the user's eyes. The receptacle fiber carrier 72 is pivotally attached to the housing 70 by providing posts at the first end of the carrier 72 that snaps into cuts or hooks 88 formed at one end of the receptacle housing 70. The holder 72 more releasably secures in place using dents or buttons formed on the carrier side, the holes 89 are engaged in the housing 70 of the receptacle. An alternative design for the receptacle fiber carrier can be used in which the carrier is molded as a single part with a cover plate or break top that can be adjusted on its base, the base having the fiber placement slots .

All the components of the connector 10 (except the cover 38 of the plug) can be formed of any durable, infrared or visible light transmission material, preferably an injection-moldable polymer such as polycarbonate, VALOX (a polyester sold by General Electric), or RADEL (a polyarylsulphone sold by Amoco). The material may include conductive fillers to return to the semiconductor components in order to minimize the riboelectric charge that may induce contamination of the fiber end, while these fillers do not unduly attenuate the radiation during the healing. The cover or boot 38 is preferably formed of a bath copolymer elastomer or module, such as that available from RTP of Winona, Minnesota, under the material number 1559X67420B. The assembly and installation of the connector 10 is direct. The plug 12 is typically mounted at the factory, although it can be "easily mounted in the field." To attach the mounting adhesive, simply place the adhesive on a syringe-type applicator (if desired, the adhesive can be provided in an applicator), over the opening in the carrier and inject the adhesive into the carrier 18. The adhesive is then cured by placing a light having a required wavelength radiation above the connector for a period of 25 seconds at A few minutes. Using lights that include the XL3000 model, available from 3M, which uses a 75 Watt tungsten source, either unfiltered or filtered to pass blue light. It is understood that also the plug 12 or receptacle 14 can be mounted on a patch cord or patch cord with any kind of optical connector at the other end of the fibers. It is recommended that the fibers used have a longer life than when they are exposed to indoor environments, such as the high strength fibers available from Minnesona Mining and Manufacturing Co. These fibers have a conventional core and coating that is surrounded by a new three layer construction, as discussed in U.S. Patent No. 5,381,504 described herein by reference. Those skilled in the art will also appreciate that the connector of the present invention can adjust discrete optical fibers or ribbons of various fibers, as well as fibers in an individual way and several modes. The fibers that are to be pre-terminated to either plug 12 or receptacle 14 must be removed, cut and cleaned. If the fibers are in the form of a ribbon that is part of a group of bundles of ribbons on a cord, then a portion of the cord liner must be cut first to reveal the ribbons. Most cables have several protective layers, and each of these layers must be removed to provide access to the fiber ribbons. Similar steps should be taken to remove the protective layers of a cable that has a discrete, individual fiber. After the fibers of the cable sheath have been removed, they are stripped. The bare fibers are then ready for cutting or splitting which can be achieved using any one of several commercially available fiber cutters, such as that shown in U.S. Patent No. 5,024,363. The cutting length for joining the fibers in the plug 12 is the distance from the fiber carrier 18 which, in the preferred embodiment, is approximately 23 mm.

For joining the fibers to the receptacle 14, the cutting length is the distance from the fiber carrier 72 which, in the preferred embodiment, is approximately 15 mm. Once the specialist is satisfied since each of the fibers has an acceptable end surface, the fibers can be removed from the cutter. The fibers may additionally be optionally provided by an asymmetric, cut-type treatment to impart an angled end surface, as taught in U.S. Patent No. 5,048,908. For the plug, the preparation of the fibers can be done after the fiber cable has been threaded through the cover or boot 38. The final assembly of the plug 12 comprises the simple steps of placing the fibers in the V-grooves. of the carrier 18 and fastening or adjusting the cover 24 on the carrier 18. A mounting accessory can be used to guide the cover 24 over the fiber carrier to prevent damage to the fibers as they are inserted into the cover. The ends of the fibers should end in the socket about 0.5 mm from the end of the cover. It is also simple to terminate the receptacle 14. The fiber carrier 72 is attached in the housing 70, first by plugging the pivot posts into the cutouts 88, and then by buckling or snapping the buttons in the holes 89. Care must be taken during placement of the fibers in the V-grooves and the union of the carrier to receptacle so as not to contaminate the tips of the fibers. The installation of the connector 10 is equally direct. The receptacle 14 is optionally mounted to any desired surface by convenient means, such as lock arms 76 (other constructions could be molded into the housing 70 from the usual molding). Multiple receptacles can also be mounted on a single module, and can be designed for the front or rear face, or sliding from the side. After the receptacle 14 is mounted, the connection is terminated by simply inserting the plug 12 into the opening 74. The plug 12 is released from the receptacle 14 by the latch 40. The dimensions of the various components of the connector 10 can vary considerably depending on of the desired application. The following approximate dimensions are considered to be example. The plug 12 has a total length of 57 mm, a width of 12 mm and a thickness of 8 mm, and the fiber carrier 18 provides clamping grooves that are 13 mm long. The plug cover 24 extends 25 mm below the carrier 18, providing an interior space that is 24 mm long, 10 mm wide and 6 mm high. The opening 74 of the receptacle 14 is 12 mm x 10 mm. Its total height and depth are 38 mm and 36 mm. The receptacle fiber carrier 72 is 20 mm long (from the end where the fibers are undulated to the fingertips 82 and 84), 12 mm wide and 1.5 mm thick. The fiber alignment slots in the fingers 82 and 84 are 12 mm long and have a maximum depth of 12 mm which adequately fits most conventional optical fibers. The inner angle of the V-groove should not be narrow as it could result in excessive friction with the fibers, but would also not be too wide since it would not keep the fibers properly guided. An interior angle of 90 ° is believed to be a good arrangement. Although the invention has been described with reference to specific embodiments, this description does not mean that it is considered in a limiting sense. The various modifications of the described embodiment, as well as alternative embodiments of the invention, will become apparent to one skilled in the art with reference to the description of the invention. Variations are possible in the plug, receptacle and carrier. For detailed discussion of the mechanical construction of a useful connector, see United States Patent No. 5, 381,498 and co-pending United States Patent Application Serial No. 08 / 577,740 and 08 / 801,058. For example, although only two pairs of fibers connected in the figures are shown, the connector 10 could adjust virtually any number of fibers (or only an individual pair). Therefore, it is contemplated that these modifications can be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Test Methods Keylar Traction Test "Cables were inserted into the plug with a non-Kevlar divergence". The liner was placed approximately 0.010 cm below the rear injection holes. The adhesive was injected manually using a 3 cubic centimeter syringe, making sure that the cavity was completely filled. Each plug was then cured with two exposures of 5 seconds, one at the top and one at the bottom with the appropriate light sources (Dymax UV adhesive, or visible light with blue filter, the adhesive of the invention with white light). Each cable was cut in half and divided until two separate cables protruded from the plug. For the Kevlar tractions, the plug was placed in an attachment that joins a Chatillon DFM100 balance.At one point, the cables consisting of the liner, Kevlar® and GGP fiber, were wrapped around a 6.25 cm diameter mandrel and they were held in place, pulled at a speed of 1.25 cm per minute to failure.

Fiber Pull Test For three fiber pulls, after the plug was placed in the fitting as described for the Kevlar pull test, "the liner was stripped by approximately four inches from the plug, exposing the Kevlar" and the GGP fiber. The GGP fiber was wrapped around the 6.25 cm mandrel and held in place. They were pulled at a speed of 1.25 cm per minute until failure. Then, the Kevlar "wound around the 6.25 cm mandrel and pulled at the same speed until the failure, the entire tensile test was accurate to 0.5 pounds or 2.2 kilograms.

Glossary CPQ Canforquinone EDMAB Ethyl-p-dimethylaminobenzoate DDPIPF6 Diphenyliodonium hexafluorophosphate Bis GMA Reaction product of diglycidyl ether of bisphenol A and 2 equivalents of methacrylic acid TEGDMA Dimetacrilate of triethylene glycol DHEPT Dihydroxyethyl-paratoluidine.

EXAMPLES Example 1 Samples of the fiber optic assemblies were made by stripping the outer sheath of the cable, trimming the Kevlar® fibers and inserting the optical fiber into a dual terminator connector.

Before bonding, the fibers were cleaned with a lint-free pad that has been wetted with isopropyl alcohol, then the fibers were inserted into the fitting. Two drops of adhesive were then added to each fiber channel in the dual termination fitting, and the connector was attached by exposing it for 25 seconds in a model 3M XL 3000 healing light that has a 75 watt tungsten source filtered to Pass blue light. In Examples Cl and C2, the adhesives used were UV curable adhesives and commercially available from Dymax Corp, Torrington CT, as Dymax 3072 and Dymax 3095, respectively. The recommended curing light, model 3000 EC was also purchased from Dymax Corp. The adhesive of the invention has the following composition (Example 1).

INGREDIENT PERCENT HEMA p / 10 ppm MEHQ 37.08% Resin BISGMA 61.79% EDMAB 0.50% CPQ 0.25% DHEPT 0.38% The tensile force needed to remove the fiber from the connector is shown in Table 1.

Table 1 Examples 2-X and Comparative Examples The samples were made according to Example 1 and tested for the strength of the unified structure. In Examples 2 and 3, an adhesive of the invention having the formulation as described below was used. These connectors then joined by exposing it for 25 seconds to a 3M XL 3000 model healing light that has a 75 watt tungsten source. For Comparative Examples C4 and C5, commercially available adhesives were used; C6 was used as purchased, C4 was modified by the addition of the tertiary photoinitiator system used in Examples 2 and 3, ie, CPQ, EDMAB and DDPIPF6 in the same amounts. Example C5 included this modification, and additionally contained 0.1 5 bengal rose.

Example 2 Example 3 Table 2 As can be seen, the commercially available adhesive does not produce the same type of unified structure as the adhesives of the invention, even when a ternary photoinitiator and additional sensitizers are added. This is true if ultraviolet light is used to cure adhesives, visible light through a broad spectrum, or filtered visible light to pass only the blue area of the spectrum.

It is noted that in relation to this date, the best method known by the applicant to carry out the present invention is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property:

Claims (10)

1. CLAIMS 1. A fiber optic connector that includes a unified structure, the structure comprising - at least one fiber optic cable comprising at least one optical fiber surrounded by a plurality of reinforcing fibers, both of which are surrounded by less a polymeric coating layer, a portion of the cable that is stripped in layers such that a terminal end of the exposed fiber is passed through an area of exposed reinforcing fibers, succeeded by a coated cable, and - a carrier for the optical cable characterized by a curable adhesive with visible light comprising a photoinitic system injected into the carrier, whereby the optical fiber, the reinforcing fibers and the carrier are joined in the unified structure by means of exposure to visible light for a period of time. of up to 30 seconds.
2. 2. A fiber optic connector that includes a unified structure, the structure comprising: - at least one fiber optic cable that it comprises at least one optical fiber surrounded by a plurality of reinforcing fibers, both of which are surrounded by at least one layer of polymeric coating, a portion of the cable that is stripped in a layer form such that a terminal end of the fibers exposed is true for an area of reinforcing fibers exposed, succeeded by an area covered cable, and - a carrier for the optical cable characterized by a curable adhesive with radiation near infrared and comprising a photoinitiator system injected into the carrier, whereby the optical fiber, the reinforcing fibers and the carrier that joins in the unified structure by means of radiation exposure near the infrared for a period of up to 30 seconds.
3. 3. An optical fiber connector according to claim 1, characterized in that the adhesive can be cured by radiation having a wavelength between 400 and 600 nanometers.
4. 4. An optical fiber connector according to claim 1 or rei indication 2, characterized in that the adhesive comprises at least one acrylate monomer.
5. 5. An optical fiber connector according to claim 4, wherein the adhesive contains at least one selected from the group consisting of hydroxypropyl methacrylate, hydroxyethyl methacrylate (HEMA) and methacrylic acid msnómero.
6. 6. An optical fiber connector according to claim 1 or claim 2, characterized in that the photoinitiator system contains an electron donor and at least one sensitizer.
7. 7. An optical fiber connector according to claim 6, characterized in that the photoinitiator system comprises a diaryliodonium salt or a sulfonium salt.
8. 8. An optical fiber connector according to claim 1 or claim 2, characterized in that the adhesive cures from 5 seconds to 30 seconds.
9. 9. An optical fiber connector according to claim 1 or claim 2, comprising a plurality of fiber optic cables.
10. 10. A method to form a structure unified in a fiber optic connector comprising at least one fiber optic cable, and a carrier therefor, each cable contains at least one optical fiber thereon, surrounded by a plurality of reinforcing fibers, both optical fibers as the reinforcing fibers that are surrounded by at least one layer of polymeric coating, the method characterized in that it comprises the steps of a) detaching a portion of the cable in layers such that a terminal end of the exposed fiber is passed through an area of fibers of reinforcement exposed, b) placing the cable on the carrier, c) injecting the curable adhesive according to the indication 1 to claim 2, on the carrier, d) exposing the adhesive to the radiation of the appropriate wavelength.