GB2057160A - Processes for producing light-conducting glass fibres - Google Patents
Processes for producing light-conducting glass fibres Download PDFInfo
- Publication number
- GB2057160A GB2057160A GB8029150A GB8029150A GB2057160A GB 2057160 A GB2057160 A GB 2057160A GB 8029150 A GB8029150 A GB 8029150A GB 8029150 A GB8029150 A GB 8029150A GB 2057160 A GB2057160 A GB 2057160A
- Authority
- GB
- United Kingdom
- Prior art keywords
- casing
- fibre
- glass
- blank
- core
- 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
Links
- 239000003365 glass fiber Substances 0.000 title claims abstract description 13
- 238000000034 method Methods 0.000 title claims description 23
- 239000011521 glass Substances 0.000 claims abstract description 37
- 239000000835 fiber Substances 0.000 claims abstract description 32
- 230000008878 coupling Effects 0.000 claims abstract description 22
- 238000010168 coupling process Methods 0.000 claims abstract description 22
- 238000005859 coupling reaction Methods 0.000 claims abstract description 22
- 239000000463 material Substances 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 230000001419 dependent effect Effects 0.000 claims 1
- 239000011162 core material Substances 0.000 description 16
- 229910003460 diamond Inorganic materials 0.000 description 3
- 239000010432 diamond Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000005355 lead glass Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4246—Bidirectionally operating package structures
-
- 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
-
- 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
- G02B6/2821—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
-
- 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
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4287—Optical modules with tapping or launching means through the surface of the waveguide
- G02B6/429—Optical modules with tapping or launching means through the surface of the waveguide by surface irregularities on the light guide, e.g. by mechanical modification of the surface of the light guide on its exterior
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Couplings Of Light Guides (AREA)
Abstract
Light-conducting glass fibres having a glass core of higher refractive index and a glass casing of lower refractive index and provided with one or more longitudinal side coupling zones in the form of an aperture or apertures in the fibre casing, are prepared in a simple manner by drawing a fibre blank consiting of a rod of core glass surrounded by a casing of casing glass in which one or more apertures have been formed in the casing. The apertures may first be formed in a tube of casing glass and a rod of core glass then inserted into the tube to form the blank, or the blank can first be prepared by providing a rod of core glass with a casing layer and forming the required apertures in this before drawing. <IMAGE>
Description
SPECIFICATION
Improvements in or relating to processes for pro- ducing light-conducting glass fibres
The present invention relates to processes for producing light-conducting glass fibres having at least one longitudinal side coupling zone which is intended for lateral input coupling or output coupling of light into or out of the fibre, and having an inner glass core of higher refractive index surrounded by a glass layer of lower refractive index which forms a casing, the refractive index of the material of the fibre changing abruptly from a higherto a lower value at the boundary of the core with the casing, and the or each coupling zone being constituted by an aperture in said casing.
Light can be input coupled into or output coupled from the core of the fibre through the aperture in the casing. The strength of the input or output coupling will be determined by the area of the aperture.
Advantageously, the aperture is in the form of a longitudinal slot in the casing, in which case the degree of the input or output coupling is determined solely by the length of the fibre and of the longitudinal slot.
Two or more apertures may be distributed peripherally round the fibre or along its length, each aperture forming an independent coupling zone.
It is an object of the invention to provide a simple process for the manufacture of glass fibres having such light coupling apertures.
According to the invention, there is provided a process for the production of a light-conducting glass fibre having at least one longitudinallyextending side coupling zone intended for lateral input or output coupling of light into or out of the fibre, said fibre comprising an inner glass core of higher refractive index surrounded by a glass layer of lower refractive index which forms a casing, the refractive index changing abruptly at the core-casing boundary, and the or each said coupling zone being constituted by an aperture in the casing of the glass fibre, said process comprising the steps of forming one or more longitudinally-extending apertures in the casing part of a fibre blank comprising a core part of said higher refractive index core part material surrounded by a casing part of said lower refractive index casing glass material and thereafter drawing said blank to form said fibre.
By the term "aperture" as used herein, is meant an opening of limited width in the casing glass layer of the fibre, or the casing part of the blank, as the case may be, forming a window therein extending to the glass core of the fibre or the core part of the blank, which window may either be empty or filled with a light-transmissive material having a refractive index greater than that of the casing glass, e.g. core glass.
In one advantageous process according to the invention, into a tube made of the casing glass material and provided with at least one opening for each coupling zone required, a rod made of a core glass material is inserted and the tube and the rod are fused together at least at one end, the rod and the tube then being drawn to form the fibre.
In another advantageous process according to the invention, for each coupling zone required, an aperture is produced in the casing of a fibre blank comprising a rod of core glass material surrounded by casing glass, and this blank is then drawn to form the fibre.
The invention will now be further described making reference to the drawing which is a schematic end-sectional view of a fibre blank for use in drawing a glass fibre by a process according to the invention.
In one form of process according to the invention using a rod/tube method, at least one aperture, for example, a longitudinal slot, is produced, using, for example, a diamond saw, in a commercially available tube made of casing glass material and is subsequently cleansed with dilute hydrofluoric acid and distilled water. The width of the slot may be set, for example, by the thickness of the sawing blade of the diamond saw and can easily be varied by varying this thickness. A cleansed glass rod made of core glass material is now inserted into the glass tube and is fused at, for example, one end to the glass tube.
This rod/tube combination is now clamped in a fibre-drawing device and conducted several times through the heating zone of the drawing furnace which is set at a temperature of about 500"C. This is to eliminate absorbed moisture from the rod/tube boundary area which would otherwise lead to the formation of bubbles during the drawing of the fibre and thus to high stray light losses. This process also requires all the precautionary measures generally taken in processes of this kind. After the drying stage, the temperature is increased to a value suitable for fibre drawing and the rod/tube combination is drawn to form a fibre in known manner.In a practical experiment, a glass tube of the AR-type marketed by the Schott Company having an internal diameter of 10 mm, an outer diameter of 12 mm and a refractive index of 1.516 was used and was slotted using a diamond saw having a length of 50 cm. The width of the slot was 1 mm. A lead glass of the type
F-7 also marketed by the Schott Company was used as the core material. After the cleansing of the tube and the glass rod (which had a diameter of 10 mm and a refractive index 1.62), the rod!tube combination was drawn at a temperature of about 700"C to form a glass fibre having a thickness of about 140 ttm with a slot in the casing.
The temperature and drawing-off speed can be so selected that the slot is entirely filled with core material. The drawing is a cross-section through a fibre blank produced in this way. This blank has a core part 1 and a casing part 2. With this type of fibre, a simpler input and output coupling of light signals can be achieved in certain applications.
Another production process according to the invention is based on the use of an already-produced fibre blank made of a rod of core glass material surrounded by casing glass in which an aperture is subsequently produced in the casing. This can be effected by sawing, etching or melting, for example, by means of a laser, parallel or at right-angles to the rod axis. It is essential that, in all cases, the casing glass is removed in a precisely defined manner at specific points so that during the subsequent fibre drawing process, light-conducting fibres having the desired coupling zones are obtained. This process has the special advantage that fibres which are provided only locally with longitudinal side coupling zones and which are not slotted over their entire length can be obtained in an extremely well defined manner. The fibre blank can be produced in known manner by the chemicai vapour deposition method.
Claims (7)
1. A process for the production of a light conducting glass fibre having at least one longitudinally-extending side coupling zone intended for lateral input or output coupling of light into or out of the fibre, said fibre comprising an inner glass core of higher refractive index surrounded by a glass layer of lower refractive index which forms a casing, the refractive index changing abruptly at the core-casing boundary, and the or each said coupling zone being constituted by an aperture in the casing of the glass fibre, said process comprising the steps of forming one or more longitudinally-extending apertures in the casing part of a fibre blank comprising a core part of said higher refractive index core part material surrounded by a casing part of said lower refractive index casing glass material, and thereafter drawing said blank to form said fibre.
2. A process as claimed in Claim 1, wherein said blank is produced by first forming one or more apertures in a tube made of casing glass material, introducing a rod made of core glass material into said tube, and fusing said rod and tube together at least at one end.
3. A process as claimed in Claim 1, wherein said blank is produced by forming one or more apertures in the casing part of a fibre blank already formed by surrounding a rod of core glass material with a continuous casing layer of casing glass material.
4. A process as claimed in any one of Claims 1 to 3, wherein the or each said aperture in the glass fibre and in said blank is in the form of a longitudinal slot.
5. A process as claimed in any one of the preceding Claims, wherein two or more said apertures in the blank casing part are distributed peripherally around said casing part to produce corresponding apertures in said fibre, each forming an independent coupling zone.
6. A process as claimed in any one of Claims 1 to 3 or Claim 5 as dependent thereon, wherein two or more apertures are distributed along the length of the blank to produce two or more corresponding apertures in the casing of said fibre, each forming an independent coupling zone.
7. A process according to Claim 1 for the production of a light-conducting glass fibre substantially as hereinbefore described with reference to the drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8029150A GB2057160B (en) | 1977-09-30 | 1978-09-26 | Processes for producing light-conducting glass fibres |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19772744129 DE2744129A1 (en) | 1977-09-30 | 1977-09-30 | CORE-COAT GLASS FIBER WITH LATERAL COUPLING AREA |
| GB8029150A GB2057160B (en) | 1977-09-30 | 1978-09-26 | Processes for producing light-conducting glass fibres |
| GB7838108A GB2005046B (en) | 1977-09-30 | 1978-09-26 | Light-conducting glass fibres |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2057160A true GB2057160A (en) | 1981-03-25 |
| GB2057160B GB2057160B (en) | 1982-09-02 |
Family
ID=27187338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8029150A Expired GB2057160B (en) | 1977-09-30 | 1978-09-26 | Processes for producing light-conducting glass fibres |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2057160B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2135473A (en) * | 1983-02-18 | 1984-08-30 | James Walter Rawson | Fibre optics element |
| GB2189900A (en) * | 1986-04-22 | 1987-11-04 | Plessey Co Plc | Optical fibre devices |
| AT397442B (en) * | 1989-02-21 | 1994-04-25 | Zehetner Johann | Processing method for optical waveguides designed with a capillary channel, and an optical component equipped with such an optical waveguide |
-
1978
- 1978-09-26 GB GB8029150A patent/GB2057160B/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2135473A (en) * | 1983-02-18 | 1984-08-30 | James Walter Rawson | Fibre optics element |
| GB2189900A (en) * | 1986-04-22 | 1987-11-04 | Plessey Co Plc | Optical fibre devices |
| GB2189900B (en) * | 1986-04-22 | 1989-11-29 | Plessey Co Plc | Optical fibre devices |
| AT397442B (en) * | 1989-02-21 | 1994-04-25 | Zehetner Johann | Processing method for optical waveguides designed with a capillary channel, and an optical component equipped with such an optical waveguide |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2057160B (en) | 1982-09-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |