GB2030318A - Optical Fibre Couplers - Google Patents

Optical Fibre Couplers Download PDF

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Publication number
GB2030318A
GB2030318A GB7930466A GB7930466A GB2030318A GB 2030318 A GB2030318 A GB 2030318A GB 7930466 A GB7930466 A GB 7930466A GB 7930466 A GB7930466 A GB 7930466A GB 2030318 A GB2030318 A GB 2030318A
Authority
GB
United Kingdom
Prior art keywords
line
fibres
fibre
optical fibre
contact
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.)
Granted
Application number
GB7930466A
Other versions
GB2030318B (en
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.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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 Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of GB2030318A publication Critical patent/GB2030318A/en
Application granted granted Critical
Publication of GB2030318B publication Critical patent/GB2030318B/en
Expired legal-status Critical Current

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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
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B6/2821—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals
    • G02B6/2835—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals formed or shaped by thermal treatment, e.g. couplers
    • 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
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • 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
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B6/2856—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers formed or shaped by thermal heating means, e.g. splitting, branching and/or combining elements

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

A coupling device is disclosed for coupling energy from a first line to a second line. The device includes a first optical fibre (57) which is connected in series with the first line and a second optical fibre (59) which is in contact with the first fibre along a certain length and is connected to the second line. Each of the fibres has a core the refractive index for light and fusing point of which exceed the refractive index for light and fusing point respectively of a covering of the fibre. The fibres may be twisted, and contact between them established by heating to melt the covering. <IMAGE>

Description

SPECIFICATION A Coupling Device Including Optical Fibres The present invention relates to a coupling device for guiding energy from a first line to a second line, which device includes optical fibres.
In order to enable fibre optical systems in which a transmitter is to be connected to several receivers and vice versa, a kind of passive coupling device, a so called T-coupler, is required.
A number of different kinds of T-couplers are shown in the literature, the technical solutions of which are rather complicated and which couplers are unsuitably designed with regard to the possibility of providing various coupling factors and low internal attenuation. The coupling factor and the internal attenuation are in this case defined as
and
P,/P0 respectively where P0 represents the input power and P1 and P2 represent the output power at the two outputs of the T-coupler.
According to the present invention there is provided a coupling device for coupling energy from a first line to a second line, which device includes a first optical fibre for connection in series with the first line and a second optical fibre in contact with the first optical fibre along a certain length and having an end for connection to the second line, wherein each of the optical fibres has a fibre core with a covering, the material of the covering having a refractive index for light and a fusing point lower than the refractive index for light and the fusing point respectively of the material of the core.
The first and second fibres could be twisted around each other along at least part of the said certain length.
Preferably, material of the coverings of each of the fibres has been fused so that the cores are in contact with each other.
The invention will now be described by way of example with reference to the accompanying drawing, in which: Figure 1 shows schematically a system with connected T-couplers, Figure 2 shows two twisted optical fibres, Figure 3 shows, greatly enlarged, a section through the fibres in Figure 2, Figure 4 shows a coupling device with four ports and Figure 5 shows a practical embodiment of a coupling device according to the invention.
The system according to Figure 1 includes a transmitter/receiver 10, a first T-coupler 11, a second T-coupler 12, a first receiver/transmitter 13 and a second receiver/transmitter 14. Optical fibres for conducting energy are connected between the units 10-11, 11-12, 11-13, and 1 2-14. It can be cause that the T-coupler 11 is connected to a first line for conducting energy from this first line to a second line 1 5 connected to the receiver/transmitter 13.
The coupling device 11 includes an optical fibre 1 7 intended to be connected in series with the first line from the transmitter/receiver 10, an optical fibre 1 9 intended to be in contact with the fibre 1 7 along a certain length at one end be connected to the second line 1 5.
Each of the optical fibres 1 7 and 1 9 has a fibre core of material (quartz) with a certain refractive index for light and a certain fusing point and a covering of a material (optical plastics material) with a lower refractive index for light and a lower fusing point than the refractive index for light and fusing point respectively of the core material.
By putting two fibres of the above kind close to each other, for example by twisting, see Figure 2, and at the same time increasing the temperature within the area of twisting (the coupling area) to a value which causes the material of the covers but not the core material to fuse, a contact between the two fibre cores can be provided. Energy (light) can then be coupled from one fibre to the other in which case the coupling factor is determined by the length along which the fibre cores are in contact with each other.
From the section shown in Figure 3, it can be seen how contact is established between the two fibres 1 7, 1 9 by fusing away material of the covers between the fibre cores 1 71 and 191.
The internal attenuatidn of the coupling device becomes low as the original fibre structure will hardly be effected at all. A device according to the invention can also be shaped as a 4-port coupler.
This is schematically shown in Figure 4 where a fibre 49 along a part of its length is twisted around a fibre 47 the fibres ending at the terminals 41, 42, 43 and 44. Energy can be transmitted from 41 to 42, 41 to 44, 43 to 42, 42 to41,42 to 43 and 44to 41.
To get a compact design and good temperature stability, fibres in a device according to the invention can be put in loops, for example, which are moulded between two glass plates, see Figure 5. A fibre 57 leads from a terminal 51 in a loop between two glass plates 55 and 56 to a terminal 52, and a fibre 59 leads from a point 571 on the loop of the fibre 57 to a terminal 53. The fibre 59 is twisted around the fibre 57 between the glass plates 55 and 56 and by the heating, previously mentioned, a great number of coupling points arise each having the cross section shown in Figure 3.
Coupling devices of the above kinds have been produced, in which the length where the two fibres contact each other is between 4 and 10 cm, which gives a coupling factor between 6 and 10 dB, an internal attenuation < 1 dB and good temperature stability.

Claims (6)

Claims
1. A coupling device for coupling energy from a first line to a second line, which device includes a first optical fibre for connection in series with the first line and a second optical fibre in contact with the first optical fibre along a certain length and having an end for connection to the second line, wherein each of the optical fibres has a fibre core with a covering, the material of the covering having a refractive index for light and a fusing point lower than the refractive index for light and the fusing point respectively of the material of the core.
2. A device according to claim 1, wherein the first and second optical fibres are twisted around each other along at least part of the said certain length.
3. A device according to claim 1 or 2, wherein material of the coverings of each of the fibres has been fused so that the cores are in contact with each other.
4. A device according to any preceding claim, wherein the fibres are in contact along at least part of a loop in the fibres.
5. A device according to claim 4, wherein the loop is sandwiched between transparent plates.
6. A coupling device, substantially in accordance with any example herein described with reference to Figures 2 to 5 of the accompanying drawing.
GB7930466A 1978-09-15 1979-09-03 Optical fibre couplers Expired GB2030318B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE7809741A SE7809741L (en) 1978-09-15 1978-09-15 CONNECTORS INCLUDING OPTICAL FIBERS

Publications (2)

Publication Number Publication Date
GB2030318A true GB2030318A (en) 1980-04-02
GB2030318B GB2030318B (en) 1982-06-30

Family

ID=20335843

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7930466A Expired GB2030318B (en) 1978-09-15 1979-09-03 Optical fibre couplers

Country Status (2)

Country Link
GB (1) GB2030318B (en)
SE (1) SE7809741L (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0093460A1 (en) * 1982-03-22 1983-11-09 Koninklijke Philips Electronics N.V. Method of manufacturing a fibre-optical coupling element
JPS60217312A (en) * 1984-04-13 1985-10-30 Nippon Telegr & Teleph Corp <Ntt> Optical cable transmission line
JPS60217313A (en) * 1984-04-13 1985-10-30 Nippon Telegr & Teleph Corp <Ntt> Distributing and coupling circuit of optical fiber
GB2165661A (en) * 1984-10-15 1986-04-16 Telephone Cables Ltd Optical fibre junction box
EP0234665A2 (en) * 1986-02-21 1987-09-02 Plessey Overseas Limited Fibre-optic coupler
WO1988007690A1 (en) * 1987-04-02 1988-10-06 British Telecommunications Public Limited Company A method of forming an optical fibre junction

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0093460A1 (en) * 1982-03-22 1983-11-09 Koninklijke Philips Electronics N.V. Method of manufacturing a fibre-optical coupling element
US4490163A (en) * 1982-03-22 1984-12-25 U.S. Philips Corporation Method of manufacturing a fiber-optical coupling element
JPS60217312A (en) * 1984-04-13 1985-10-30 Nippon Telegr & Teleph Corp <Ntt> Optical cable transmission line
JPS60217313A (en) * 1984-04-13 1985-10-30 Nippon Telegr & Teleph Corp <Ntt> Distributing and coupling circuit of optical fiber
GB2165661A (en) * 1984-10-15 1986-04-16 Telephone Cables Ltd Optical fibre junction box
GB2191597A (en) * 1986-02-21 1987-12-16 Plessey Co Plc Intertwined monomode fibre-optic coupler
EP0234665A2 (en) * 1986-02-21 1987-09-02 Plessey Overseas Limited Fibre-optic coupler
US4775209A (en) * 1986-02-21 1988-10-04 Plessey Overseas Limited Fiber-optic coupler comprising intertwined monomode fibers of different diameter
EP0234665A3 (en) * 1986-02-21 1989-05-24 Plessey Overseas Limited Fibre-optic coupler
GB2191597B (en) * 1986-02-21 1989-11-15 Plessey Co Plc Interwined monomode fibre-optic coupler.
WO1988007690A1 (en) * 1987-04-02 1988-10-06 British Telecommunications Public Limited Company A method of forming an optical fibre junction
EP0287252A1 (en) * 1987-04-02 1988-10-19 BRITISH TELECOMMUNICATIONS public limited company A method of forming an optical fibre junction
US4896932A (en) * 1987-04-02 1990-01-30 British Telecommunications Public Limited Company Method of forming an optical fibre junction

Also Published As

Publication number Publication date
SE7809741L (en) 1980-03-16
GB2030318B (en) 1982-06-30

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