EP0233242A1 - Preforme avec indice de refraction a gradient et son procede de fabrication - Google Patents

Preforme avec indice de refraction a gradient et son procede de fabrication

Info

Publication number
EP0233242A1
EP0233242A1 EP86904958A EP86904958A EP0233242A1 EP 0233242 A1 EP0233242 A1 EP 0233242A1 EP 86904958 A EP86904958 A EP 86904958A EP 86904958 A EP86904958 A EP 86904958A EP 0233242 A1 EP0233242 A1 EP 0233242A1
Authority
EP
European Patent Office
Prior art keywords
preform
refractive index
tube
polymerization
monomers
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Withdrawn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
EP86904958A
Other languages
German (de)
English (en)
Inventor
Ivar M. Dahl
Gunnar Fonne
Niels Peter Thorshaug
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.)
Norsk Hydro ASA
Original Assignee
Norsk Hydro ASA
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
Application filed by Norsk Hydro ASA filed Critical Norsk Hydro ASA
Publication of EP0233242A1 publication Critical patent/EP0233242A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00663—Production of light guides
    • B29D11/00721—Production of light guides involving preforms for the manufacture of light guides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/05—Filamentary, e.g. strands
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00663—Production of light guides
    • B29D11/00682—Production of light guides with a refractive index gradient
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • 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

Definitions

  • the present invention concerns a preform with a graded refractive index and a method for the construction of preform materials for drawing or extruding optical fibres.
  • the transmission speed will depend on the refractive index of that material. If we apply electro ⁇ magnetic waves with the same speed as visible light, we may, to make it simple, say that the electromagnetic wave is transmitted through the material with the speed of light. If we then imagine that the light is to be transmitted in a material with a larger refractive index than for instance air, then the speed of light will be slower in this material than in air. This is in accordance with Snell's law.
  • Light that does not follow the fibre axis but is transmitted outside the axis will either be refracted from the outer limit of the fibre, i.e. the area between the fibre material and the cladding, or it may escape from the fibre. This means that the light that travels through the fibre, will lose some intensity on its way from the place of origin to its destination. We say that the light is attenuated. Moreover, the refracted light will arrive with a certain phase displacement in relation to the light which follows the fibre axis because of the long distance the reflected light must travel.
  • stepped index fibres i.e. fibres where the material has a uniform refractive index from the axis to the next alteration of the refractive index, which is usually between the inner core of the fibre and the cladding.
  • optical fibres which are optically non-homogenous (graded index profile) i.e. the refractive index changes continually from a higher refractive index in the fibre axis to a lower refractive index peripheral fibre, the light which is transmitted through the fibre will not be refracted as in stepped index fibres, but will be continually bent toward the axis.
  • U.S. patents 4.138.194 and 4.161.500 describe a method for the construction of preforms where the material is optically homogenous.
  • a copolymer is used based on a methyl meth- acrylate and a small amount of additive consisting of other acrylates and methacrylates.
  • the finished preform is in turn used for extruding optical fibres.
  • DE patent application No. 14 97 545 also describes con ⁇ struction of stepped index fibres where the fibre core is based on polystyrene, and where the fibre cladding is based on polymethyl methacrylate.
  • the construction consists of filling the core material in a tube of polymethyl meth ⁇ acrylate, so as to produce a preform with a polystyrene core and a polymethyl methacrylate cladding. The preform is then heated until it becomes pliable, whereafter the optical fibre is extruded.
  • Optical fibres produced from preforms of the above-mentioned type will be optically homogenous, and thus be less suited for transmission of information over long distances.
  • optical fibres from synthetics with a graded index where the refractive index is continually reduced from the fibre axis out toward the peripheral fibre.
  • this is done by bringing together monomers with almost identical reaction parameters and solubility parameters, but with different refractive indices while con ⁇ tinually changing the mole ratio of the monomers.
  • the monomers are thereafter deposited on a rotating wall of glass, quartz and/or another suitable material, for instance a tube-shaped polymer material suitable for the cladding.
  • the monomers are then polymerized according to an accepted method, for instance by using initiators based on peroxide either by radiation, e.g. by applying UV radiation or by applying IR radiation for heating or a combination of one or two of the above-mentioned methods of polymerization.
  • initiators based on peroxide either by radiation, e.g. by applying UV radiation or by applying IR radiation for heating or a combination of one or two of the above-mentioned methods of polymerization.
  • UV radiation should have a fre ⁇ quence which coincides with the lowest UV absorption in the glass.
  • Fig. 1 shows a sideview of an apparatus for the construction of preforms.
  • the apparatus shown in Fig. 1 consists of an outer tube (1) of glass, quartz or plastics.
  • Glass here means all qualities of glass.
  • Plastics will include both water soluble and non-soluble materials, both natural and synthetic.
  • the tube (1) is plugged with the end pieces (2' and 2 " ) which have several functions. First of all the end pieces (2 1 and 2") will act as a supporting member for the tube (1), and secondly function as pivoting point for the tube (1).
  • the device for the rotation of the tube (1) may be of a traditional kind, where the pieces (2* and 2") are equipped with shaft ends, or rotation can take place directly over the end pieces when these are fastened to a rotating bearing.
  • the device for the rotation of the tube is not part of the invention and is therefore not shown in Fig. 1.
  • the end pieces (2' and 2") are fastened to the tube (1) in a traditional way, for instance by screws, by tightening with O-ring ⁇ of an inert material or by another form of friction coupling between the end pieces and the tube.
  • the end pieces may be made of metal and/or plastics. It would be an advantage if the material in the end pieces is resistent to corrosion by the monomers and that they are heat resistant, i.e. that they do not lose their shape through exposure to heat.
  • the end pieces (2 M ) are shown as a bushing (3) and as a cannula (4) which can be moved backwards and forwards in the tube (1) through the end piece (2"). Such movement is controlled by means of a motor (5), and is indi ⁇ cated by a double arrow over the cannula (4).
  • the tube (1) between the end pieces (2' an 2" one may for example feed nitrogen as inert gas (I) into the tube (1) along the bushing (3).
  • the reagents in this case consisting of the monomers M. and/or M 2 or of pure monomers or a mixture of them, are led through the cannula. It is not imparative to use only one or two monomers, as it is possible to visualize monomer combinations consisting of both two and more monomers. Therefore, the invention does not set a limit as to how many monomers are to be used or which will be utilized.
  • the deciding factor for the choice of monomers is the optical characteristics and other physical data for the finished product.
  • the cannula (4) is coupled to the tube for feeding monomer (M, and M,), UV-initiator, chain transfer and, if appli ⁇ cable, other auxiliary material (H) suitable for the purpose.
  • the apparatus described above has two movements. In the first place the tube (1) with the end pieces (2* and 2") will rotate. Secondly, the cannula (4) will move backwards and forwards inside the tube (1) so that after a while the inner surface of the tube will be coated with material from the cannula (4).
  • the preform apparatus rotates at such a high speed that the materials will be evenly distributed.
  • rotation speeds between 500 and 2 000 rpm, preferably around 1 000 rpm.
  • the cannula (4) will receive separate supplies of the monomers M, and , but it may also be an advantage to have a third supply, for instance chain transfer and/or UV initiator.
  • the preform con ⁇ structed is as optically clean as possible, i.e that it con ⁇ tains a minimum of materials that may distort the optical signals and attenuate them. It is therefore an advantage to initiate the polymerization and to carry this out by means of UV radiation.
  • Fig. 1 shows a device (7) for radiation with UV beams. Since the tube (1) rotates at a comparatively high speed, the radiation must be considered as being even over the entire inner surface of the tube (1).
  • the purpose of the above-mentioned apparatus is to construct a preform with an attenuating refractive index from the rotation axis of the preform out toward the periphery.
  • stepped index fibres any type of optical fibre according to the stepped index fibre principle if the refrac ⁇ tive index profile is evenly or parabolically attenuating or diminishing in another way. It is also possible to produce stepped index fibres according to the method mentioned in that the polymer layers inside the tube (1) are built up by polymers, layer after layer, with an increasing refractive index from the tube (1) and toward the axis of the preform.
  • UV radiation of monomers may take place at all temperatures, but we choose a temperature which does not lead to temperature increases in the preform.
  • room temperature approximately 20 C
  • UV radiation is very suitable if polymerization is carried out with UV radiation.
  • Monomer M 2 Low refractive index 100 to 0 mole % UV-initiator 0.01 to 1 mole %
  • solubility parameters e , and cf ⁇ of monomers M, and M 2 ought not to have a larger difference than •A-cT-s 1.0, but this is not of vital importance since there are monomer systems where the difference mentioned is larger but where the monomers nevertheless still are soluble.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)

Abstract

Préforme possédant un indice de réfraction à gradient et constituée d'un matériau synthétique, c'est-à-dire de composés polymères optiquement propres fabriqués à l'aide d'une technique dans laquelle un tube en rotation (1) présentant des parties terminales (2' et 2'') reçoit des monomères comportant des additifs via une canule (4) dans un flux continu de sorte que la composition monomère évolue progressivement d'un indice de réfraction inférieur vers un indice de réfraction supérieur en partant de la périphérie de la préforme pour aller vers son axe de rotation. La polymérisation du matériau monomère déposé lors de la rotation du tube (1) est provoquée au moyen d'un rayonnement aux UV et/ou d'une polymérisation du radical.
EP86904958A 1985-08-22 1986-08-20 Preforme avec indice de refraction a gradient et son procede de fabrication Withdrawn EP0233242A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO853303 1985-08-22
NO853303A NO853303L (no) 1985-08-22 1985-08-22 Preform med gradert brytningsindeks og fremgangsmaate for fremstilling av samme.

Publications (1)

Publication Number Publication Date
EP0233242A1 true EP0233242A1 (fr) 1987-08-26

Family

ID=19888437

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86904958A Withdrawn EP0233242A1 (fr) 1985-08-22 1986-08-20 Preforme avec indice de refraction a gradient et son procede de fabrication

Country Status (4)

Country Link
EP (1) EP0233242A1 (fr)
JP (1) JPS63500685A (fr)
NO (1) NO853303L (fr)
WO (1) WO1987001071A1 (fr)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2682969B1 (fr) * 1991-10-25 1993-12-03 Verre Fluore Sa Procede de fabrication en continu de fibres en materiau polymerisable, notamment de fibres optiques polymeres.
WO1994004949A1 (fr) * 1992-08-17 1994-03-03 Yasuhiro Koike Procede de production de transmetteurs de lumiere en plastique
EP0664463A4 (fr) * 1993-06-16 1997-08-20 Sumitomo Electric Industries Materiau de base pour fibre optique plastique, sa production, et procede et appareil pour sa production.
WO1995000868A1 (fr) * 1993-06-18 1995-01-05 Sumitomo Electric Industries, Ltd. Procede et appareil de production de matiere plastique de base pour fibres optiques
US5846456A (en) * 1996-01-17 1998-12-08 National Science Council Method of making gradient index optical element
NL1002317C2 (nl) * 1996-02-13 1997-08-14 Univ Eindhoven Tech Werkwijze voor het vervaardigen van optische staafvormige polymere vormdelen met een gradiënt voor de brekingsindex, vormdelen verkregen volgens deze werkwijze en optische lens en optische vezel onder toepassing hiervan.
WO1998010916A1 (fr) * 1996-09-12 1998-03-19 University Of Florida Nouveau procede de fabrication pour objets dont les proprietes connaissent des variations radiales
DE19822684A1 (de) * 1998-05-20 1999-12-09 Deutsche Telekom Ag Verfahren zur Erzeugung von Gradientenindex-Brechzahlprofilen in polymeren optischen Fasern
KR100359907B1 (ko) * 2000-01-11 2002-11-07 삼성전자 주식회사 플라스틱 광섬유용 모재의 제조방법 및 그 플라스틱광섬유용 모재
KR100368692B1 (ko) * 2000-03-21 2003-01-24 옵티미디아(주) 반경 방향으로 변화하는 물성을 지니는 봉형 고분자 모재,그의 제조방법 및 이에 사용되는 장치
AU2001253412A1 (en) 2000-04-12 2001-10-30 Nanoptics, Inc. Method and apparatus for manufacturing plastic optical transmission medium
JP2002189103A (ja) * 2000-12-20 2002-07-05 Asahi Optical Co Ltd 屈折率分布型光学素子及びその製造方法
ATE341434T1 (de) 2001-07-18 2006-10-15 Samsung Electronics Co Ltd Höhlungvermeidender reaktor und verfahren zur herstellung eines halbzeuges für optische fasern in einem solchen reaktor

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS525857B2 (fr) * 1972-10-23 1977-02-17
US3999834A (en) * 1973-08-14 1976-12-28 Kanebo, Ltd. Method for producing optical fibers and resulting fibers
US4022855A (en) * 1975-03-17 1977-05-10 Eastman Kodak Company Method for making a plastic optical element having a gradient index of refraction
US4521351A (en) * 1983-01-27 1985-06-04 Nippon Sheet Glass Co., Ltd. Process for producing light-transmitting element of synthetic resin
EP0144712B1 (fr) * 1983-11-02 1988-03-30 Sumitomo Chemical Company, Limited Fibre optique
US4582655A (en) * 1983-11-25 1986-04-15 Eastman Kodak Company Production of optical element with a varying refractive index

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8701071A1 *

Also Published As

Publication number Publication date
NO853303L (no) 1987-02-23
JPS63500685A (ja) 1988-03-10
WO1987001071A1 (fr) 1987-02-26

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Inventor name: FONNE, GUNNAR

Inventor name: THORSHAUG, NIELS, PETER