EP1472080A1 - Fibre optique a base de polymere a gradient d'indice, et son procede de production - Google Patents

Fibre optique a base de polymere a gradient d'indice, et son procede de production

Info

Publication number
EP1472080A1
EP1472080A1 EP02806247A EP02806247A EP1472080A1 EP 1472080 A1 EP1472080 A1 EP 1472080A1 EP 02806247 A EP02806247 A EP 02806247A EP 02806247 A EP02806247 A EP 02806247A EP 1472080 A1 EP1472080 A1 EP 1472080A1
Authority
EP
European Patent Office
Prior art keywords
methacrylate
optical fiber
nozzle
fluoroacrylate
dopant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02806247A
Other languages
German (de)
English (en)
Other versions
EP1472080A4 (fr
Inventor
Zhen Zhen
Xinhou Liu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Components Inc
Original Assignee
General Components Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/038,964 external-priority patent/US20030132536A1/en
Priority claimed from US10/039,046 external-priority patent/US20030134119A1/en
Application filed by General Components Inc filed Critical General Components Inc
Publication of EP1472080A1 publication Critical patent/EP1472080A1/fr
Publication of EP1472080A4 publication Critical patent/EP1472080A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02033—Core or cladding made from organic material, e.g. polymeric material
    • G02B6/02038—Core or cladding made from organic material, e.g. polymeric material with core or cladding having graded refractive index
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
    • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
    • D01F8/10—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one other macromolecular compound obtained by reactions only involving carbon-to-carbon unsaturated bonds as constituent

Definitions

  • the instant invention generally relates to polymer based optical fiber which is suitable for use in telecommunications.
  • the present invention relates to an improved graded index (GI) polymer optical fiber (POF) and the methods of making the improved GI POF.
  • GI graded index
  • POF polymer optical fiber
  • Typical, 10/100 Ethernet line area networks are connected using twisted pair Category (“Cat”) 3/5 cabling.
  • Cat 3/5 cabling is effective for LAN connections it is far from a perfect solution. For Ethernet 10/100 speeds, Cat 3/5 cabling is sufficient.
  • network managers will need to replace Cat 5 cabling with optical fiber.
  • all twisted pair cabling is susceptible to RF interference, which limits its applicability in noisy RF environments.
  • One transmission layer solution to the bandwidth and RF limitations of twisted pair cable is to replace twisted pair cable with either glass optical fiber (GOF) or plastic optical fiber (POF).
  • GAF glass optical fiber
  • POF plastic optical fiber
  • GOF although offering far superior optical transmission properties than POF, is not commercially practicable for most LANs ( ⁇ 150m) with a large numbers of connections because of the high connectivity costs associated with terminating glass optical fiber. Cutting and terminating GOF is expensive for a number or reasons.
  • Typical GOF such as 50/125 multimode fiber or 10/125 single mode fiber, has a very small diameter and it is brittle. The relatively small diameter of GOF, requires that the angle of the incident light be tightly controlled. In order to tightly control the angle of the incident light into a fiber, the fiber must be carefully cut and inserted into a precision connector. Accordingly, special tools, trained technicians and expensive, precision connectors are required to terminate GOF.
  • POF offers many of the benefits of GOF, namely supporting much higher data rates than twisted pair copper cable and immunity to RF interference, but without the high connectivity costs associated with GOF.
  • POF typically has a much larger diameter - approximately 1mm - relative to the diameter of GOF. This larger diameter permits lower connector tolerances without a loss of optical coupling efficiency and does not require the expensive polishing step required for terminating GOF.
  • POF can be terminated by an untrained worker using a hot plate. Additionally, POF links may employ low cost 500-800nm LEDs.
  • POF may be characterized by its radial index of refraction.
  • the radial index of refraction is essentially a step function, in graded index (GI)
  • GI POF graded index
  • One GI POF comprises multiple annular layers of copolymers. See U.S. Patent No. 6,307 ,992B (the'992 Patent).
  • a layer of a GI POF refers to either the core or the annular layers surrounding the core in a GI POF .
  • Each polymer of the copolymer pair is characterized by a different index of refraction. Accordingly, by varying the copolymer composition of each layer the index of refraction may be graded as a function of the fiber radius.
  • the GI POF according the '992 Patent contains a number of important limitations. First, because the polymers comprising each layer are large molecules, the polymers cannot readily diffuse between layers. Thusly, as indicated by Figure 1 in the '992 Patent, the index of refraction of the POF as a whole, is not a smooth radial function, but a series of step functions for each layer. Secondly, in order to avoid inter-layer and intra-layer phase separation, the composition of each layer is limited and thus the range of refractive indices is limited.
  • Two closely related GI POFs are comprised of multiple annular layers in which each layer comprises multiple polymers.
  • the GI POF according to these inventions contain the same deficiencies as the '992 application for the same reasons.
  • the polymer mixtures comprising each layer tend to produce heterogeneous structures due to microscopic or macroscopic phase separation and hence have large scattering losses.
  • one object of the present invention is a GI POF which is formed from multiple, annular layers of substantially of one polymer.
  • Another object of the present invention is an improved GI POF where the radial index of refraction may be varied without compromising the thermodynamic stability of the POF.
  • Another object of the present invention is an improved GI POF where the index of refraction more closely approximates a smooth, continuous function of the POF radius.
  • a still further object of the present invention is a POF with increased maximum bandwidth.
  • a still further object of the invention is a method of making an improved GI POF with the foregoing improvements over the art.
  • One embodiment of the invention is a multi layer GI POF where each layer comprises essentially one polymer and one or more dopants.
  • Each layer may comprise the same or different polymers although it is preferred that each layer comprise the same homopolymer.
  • Suitable polymer may be formed from polymerization of monomers or prepolymers of methacrylate, styrene, or their halogenated derivatives.
  • Useful dopants include cyclic or acyclic organic compounds of less than about 20 carbons, alkyl metal oxides or rare earth alkyl oxides.
  • Another embodiment of the invention is a method of making the GI POF according to the invention comprising the steps of preparing at least three spinning materials having different refractive indices, each of the spinning materials being made of at least one polymer and at least one dopant, feeding the spinning materials to a concentric nozzle so that the refractive index decreases toward the outer periphery, and thereby extruding the spinning materials through the nozzle and allowing the dopant or dopants to diffuse between adjacent layers of the fiber within the nozzle, after extrusion from the nozzle or within the nozzle and after extrusion from the nozzle.
  • Figures la-b illustrate a GI POF according to the invention.
  • Figure 2 shows a representative radial index of refraction of the GI POF fabricated according to Example 1.
  • Figure 3 shows a representative index of refraction of the GI POF fabricated according to Example 2.
  • Figure 4 shows a representative index of refraction of the GI POF fabricated according to Example 3.
  • Figures la-b illustrate a GI POF according to the invention.
  • Figure la is a cross- sectional view and
  • Figure lb is a longitudinal section.
  • the GI POF according to the invention comprises multiple layers and each layer may be characterized by its polymer/dopant concentrations and by its radial index of refraction.
  • Figure 1 only shows 3 layers, there in no inherent limitation on the number of layers, the fiber diameter, or the fiber length of the GI POF according to the invention. In general as the number of layers in a GI POF is increased, the bandwidth and loss characteristics of the GI POF may be improved.
  • GI-POF may range from about 0.5mm to about 2mm, with about 1mm preferable.
  • a given optical fiber may comprise from 3 and 30 layers. For most optical transmission applications, including 10/100 Ethernet cabling, 5-10 layers are sufficient.
  • a preferred embodiment of the invention comprises five layers, the diameter of the central layer is approximately 0.25mm, the thickness of next three layers (the second, third, and fourth layers) is approximately 0.075mm and the outer layer (the fifth layer) is approximately 0.15mm.
  • the GI POF may have numerical apertures of approximately 0.1 to approximately 0.5. Lower numerical apertures cause bending losses and coupling losses. Higher numerical apertures limit the maximum bandwidth. Accordingly, preferred numerical apertures are between approximately 0.2 and approximately 0.3
  • a preferred protective layer comprises a copolymer of approximately 65-95% by weight vinylidene fluouride and approximately 5-35% by weight of Teflon AF.
  • Each layer in the GI POF according to the invention is preferably formed from principally one polymer and one or more dopants.
  • a polymer is any compound formed by polymerizing constituent monomers or prepolymers.
  • each layer is chemically similar at much smaller length scale than is the current GI POFs because it is essentially a homopolymer composition.
  • each layer of the GI POF according to the invention is like a solid state version of a solvated solute.
  • the polymers form a "solvation shell" around uniformly distributed dopant molecules. Accordingly, phase separation effects and interfacial scattering effects are mitigated.
  • the dopant is a small molecule relative to the polymer chains, and because each layer is comprised of essentially the same polymer, the dopant can readily diffuse within a layer and between layers, thus permitting matching of the index of the refraction between the POF layers.
  • GI POF chemical properties of a copolymer system will approach a homopolymer system as the concentration of one polymer approaches unity or if the copolymers have nearly identical chemical properties. It thus follows that GI POF according to the invention may also be formed: 1) from a copolymer system if one polymer is in great excess (>80% by molar stoichiometry) or 2) if each polymer has very similar chemical properties, from a mixture of polymers.
  • the relevant chemical properties are the bulk density of each copolymer, the speed of polymerization of each copolymer and the bulk index of refraction of each copolymer.
  • GI POF In general the bulk density of each copolymer, the speed of polymerization of each copolymer and index of refraction of each copolymer should not vary by more than 3% and even more preferably, should not vary by more than 1.5%. It thus also follows, that GI POF according to the invention may be formed from multiple copolymer layers each containing one or more dopants subject to the above limitations. Polymers for constructing POF are well known in the art. Many of the polymer systems which may be used for constructing POFs employ polymerization reactions of methacrylates, styrenes or their respective derivatives. Since there are cost structure advantages for employing 500-800nm LEDs, it is important to minimize optical absorption between 500-800nm.
  • a significant source of optical absorption in these frequencies is caused by vibrations of the OH, CH, and NH bonds, all of which are common to methacrylate and styrene based polymers.
  • hydrogen atoms may be replaced by heavier substituents, such as halogen atoms.
  • halogen substitution also permits adjusting the bulk index of refraction of the halogenated polymers relative to the index of refraction of the unsubstituted polymers. For example, substitution of hydrogen atoms in methacrylate and styrene polymers with fluorine atoms tends to decrease the index of refraction. By contrast, substitution of chlorine atoms tends to increase the index of refraction in the same polymer systems.
  • a dopant refers to any compound which is mixed with a polymer to adjust the index of refraction of the resulting polymer/dopant combination above or below the index of refraction of the pure polymer.
  • dopants should be non-polymerizing, low molecular weight compounds which will easily diffuse through a polymer matrix and be thermally stable at polymer curing temperatures.
  • dopants which may readily diffuse through a polymer matrix the refractive index of a given layer and the refractive index across two layers may be closely matched.
  • the refractive index of a particular polymer/dopant system is a function of the concentration and particular polymer(s) and dopant(s) employed.
  • the refractive index of the pure polymer may in general be increased by adding dopants which are larger than the organic groups comprising the polymer framework. Conversely, the refractive index of the pure polymer may be in general be decreased by adding dopants which are smaller than the organic groups comprising the polymer framework. Additionally, dopants which have an index of refraction varying as a function of applied electric, magnetic, or electromagnetic fields may be used to create a GI POF where the index of refraction may be adjusted as a function of an applied field or an optical pumping source. Suitable dopants include linear or branched, saturated or unsaturated, cyclic or acyclic organic compounds with less than about 20 carbons.
  • Dopants are only limited by the requirements that they must modify the index of refraction of a pure polymer when mixed with the polymer and they must be sufficiently small to effectively diffuse throughout the polymer matrix during the GI POF formation process.
  • Some dopants which may be employed to form the GI POF according to the invention include diphenyl phthalate, phenyl benzoate, benzylbutylphthalate, benzyl benzoate, diphenyl sulfide, 3- phenyl-1-propanol, benzyl methacrylate, halogenated cyclic compounds, such as bromobenzene, 1,4 dibromobenzene, bromonapthalene, 1, 2, 4-trichloro benzene, o- dichlorobenzene, m-dichlorobenzene, 1,2-dibromethane, phthalic acids, benzoic acids, naphthalenes, cyclic ethers such as dibenzyl ether, phenoxy
  • Dopant concentrations in each layer may range from about 0% to about 30% by weight of each layer. At the high end of the dopant concentration range, consideration of the particular dopant and polymers may be required in order to mitigate phase separation, however, because of the relatively small size of the dopant molecules relative to the polymer chains, the phase separations concerns would be less than in a copolymer systems with comparable copolymer concentrations.
  • Another embodiment of the invention is a method for fabricating the GI POF according to the invention.
  • a first step for each layer of the GI POF according to the invention, essentially one kind of monomer and one or more dopants are mixed to form a polymer/dopant material suitable for spinning.
  • the spinning materials produced in step one are extruded to form a multi-layered GI POF.
  • the fiber of step two is drawn to produce a GI POF of a given diameter.
  • each layer preferably comprises essentially a homopolymer, as was discussed in the foregoing, each layer may also comprise a copolymer.
  • one or more monomers may also mixed with one or more dopants to form a copolymer/dopant spinning material.
  • the radial index of refraction of each layer is controlled by the particular polymers, dopants and their respective concentrations used to form each layer.
  • the index of refraction of each layer is controlled by the bulk index of refraction of the pure polymer.
  • the bulk index is then adjusted up or down in proportion to the concentration of the dopants in each layer.
  • the polymerization step may be achieved in a batch or continuous process.
  • the temperature, heating time and heating profile required to polymerize each polymer/dopant combination is specific to each polymer/dopant combination and is either within knowledge of one ordinarily skilled in art or may be determined by one ordinarily skilled in the art without undue experimentation.
  • each spinning material is extruded through a concentric nozzle to produce a multi layer GI POF fiber.
  • the extrusion process occurs preferably between
  • a diffusion tube is a post extrusion cylindrical chamber that is maintained at a temperature such that when the extruded multi layer fiber passes through the tube, the dopants may diffuse between adjacent layers.
  • the extruded multi-layer fiber is then drawn from the exit die of the concentric nozzle and/or diffusion tube to a desired diameter using drawing processes well known in the art. The present invention is further illustrated by the following examples. Example 1
  • Example 1 discloses a 5 layer GI POF in which each layer comprises a poly methyl methacrylate (“PMMA”) homopolymer doped with bromobenzene and a method of making the same.
  • PMMA poly methyl methacrylate
  • step one five spinning materials are produced having varying refractive indices.
  • bromobenzene is mixed with methyl methacrylate (hereinafter “MMA”), a polymerization initiator, benzoyl peroxide (hereinafter “BPO”), and a chain transfer agent, normal butyl mercaptan (hereinafter “nBM”) according to the following:
  • MMA methyl methacrylate
  • BPO benzoyl peroxide
  • nBM normal butyl mercaptan
  • the spinning materials are polymerized at 75° C for approximately 24 hours by methods commonly known in the art.
  • each spinning material is extruded at 210° C through a concentric circular nozzle.
  • Spinning material No. 1 forms the fiber core and spinning material Nos. 2-5 form each consecutive layer with spinning material No. 5 forming the outermost layer.
  • the multi-layered fiber produced by the extrusion process is 10 millimeters in diameter and 5 to 1000 millimeters in length.
  • step three the multi-layer fiber is then drawn from the die head at one meter per second at the temperature of the die head to the desired diameter of 1 millimeter by methods commonly known in the art.
  • Figure 2 shows a representative radial index of refraction of the GI POF fabricated according to Example 1.
  • Example 2 discloses another 5 layer GI POF in which each layer comprises a PMMA homopolymer doped with bromobenzene and a method of making the same. The same method described in Example 1 is used to produce the fiber of Example 1 except as noted below.
  • the spinning materials for Example 2 are as follows: Spinning Material #1
  • Example 3 shows a representative radial index of refraction of the GI POF fabricated according to Example 2.
  • Example 3 discloses another 5 layer GI POF in which each layer comprises a PMMA homopolymer doped with bromobenzene and a method of making the same. The same method described in Example 1 is used to produce the fiber of Example 3 except as noted below.
  • the spinning materials for Example 3 are as follows:

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)

Abstract

Dans un mode de réalisation, l'invention concerne une fibre optique à base de polymère à gradient d'indice multicouche dont chaque couche comprend sensiblement un polymère et au moins un dopant. Chaque couche peut comprendre un seul polymère ou différents polymères, bien qu'il soit préféré que chaque couche comprenne un seul homopolymère. Des dopants utiles ne peuvent être des composés organiques cycliques ou acycliques comprenant moins de 20 atomes de carbone environ, des oxydes métalliques d'alkyle des terres rares. Dans un autre mode de réalisation, l'invention concerne un procédé de production de ladite fibre optique à base de polymère à gradient d'indice.
EP02806247A 2001-12-31 2002-12-27 Fibre optique a base de polymere a gradient d'indice, et son procede de production Withdrawn EP1472080A4 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US10/038,964 US20030132536A1 (en) 2001-12-31 2001-12-31 Method of making a graded index polymer optical fiber
US10/039,046 US20030134119A1 (en) 2001-12-31 2001-12-31 Graded index polymer optical fiber and a method of making the same
US39046 2001-12-31
US38964 2001-12-31
PCT/US2002/041595 WO2003057473A1 (fr) 2001-12-31 2002-12-27 Fibre optique a base de polymere a gradient d'indice, et son procede de production

Publications (2)

Publication Number Publication Date
EP1472080A1 true EP1472080A1 (fr) 2004-11-03
EP1472080A4 EP1472080A4 (fr) 2005-10-12

Family

ID=26715685

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02806247A Withdrawn EP1472080A4 (fr) 2001-12-31 2002-12-27 Fibre optique a base de polymere a gradient d'indice, et son procede de production

Country Status (5)

Country Link
EP (1) EP1472080A4 (fr)
JP (1) JP2005517204A (fr)
AU (1) AU2002367297A1 (fr)
TW (1) TW200306250A (fr)
WO (1) WO2003057473A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7590324B1 (en) * 2008-07-24 2009-09-15 Corning Incorporated Double-clad optical fibers and devices with double-clad optical fibers
EP3994297A1 (fr) * 2019-07-02 2022-05-11 Essilor International Impression 3d fdm de lentille optique avec une clarté et une résistance mécanique élevées

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0942301A1 (fr) * 1996-03-28 1999-09-15 Mitsubishi Rayon Co., Ltd. Fibre optique a indice de refraction reparti et procede de fabrication

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6106745A (en) * 1995-11-30 2000-08-22 Akzo Nobel Nv Method of making graded index polymeric optical fibers

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0942301A1 (fr) * 1996-03-28 1999-09-15 Mitsubishi Rayon Co., Ltd. Fibre optique a indice de refraction reparti et procede de fabrication

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
See also references of WO03057473A1 *
ZHANG F ET AL: "Refractive index distribution of graded poly(methyl methacrylate) preform described by self-diffusion approaches of free-volume theory in a ternary system" POLYMER, ELSEVIER SCIENCE PUBLISHERS B.V, GB, vol. 41, no. 26, 15 December 2000 (2000-12-15), pages 9155-9161, XP004208368 ISSN: 0032-3861 *

Also Published As

Publication number Publication date
AU2002367297A1 (en) 2003-07-24
JP2005517204A (ja) 2005-06-09
EP1472080A4 (fr) 2005-10-12
WO2003057473A1 (fr) 2003-07-17
TW200306250A (en) 2003-11-16

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