GB2261524A - Optical fibre connecting system - Google Patents
Optical fibre connecting system Download PDFInfo
- Publication number
- GB2261524A GB2261524A GB9123705A GB9123705A GB2261524A GB 2261524 A GB2261524 A GB 2261524A GB 9123705 A GB9123705 A GB 9123705A GB 9123705 A GB9123705 A GB 9123705A GB 2261524 A GB2261524 A GB 2261524A
- Authority
- GB
- United Kingdom
- Prior art keywords
- optical fibre
- fibre
- connector
- length
- optical
- 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- Withdrawn
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 62
- 239000000835 fiber Substances 0.000 claims abstract description 25
- 238000012360 testing method Methods 0.000 claims description 15
- 238000002310 reflectometry Methods 0.000 claims description 10
- 238000005253 cladding Methods 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 claims description 4
- 230000001902 propagating effect Effects 0.000 claims 1
- 239000000499 gel Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 2
- 238000001579 optical reflectometry Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 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
- G02B6/36—Mechanical coupling means
- G02B6/38—Mechanical coupling means having fibre to fibre mating means
- G02B6/3807—Dismountable connectors, i.e. comprising plugs
- G02B6/381—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres
- G02B6/3818—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres of a low-reflection-loss type
- G02B6/3822—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres of a low-reflection-loss type with beveled fibre ends
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
-
- 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
- G02B6/241—Light guide terminations
- G02B6/243—Light guide terminations as light absorbers
-
- 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
- G02B6/36—Mechanical coupling means
- G02B6/38—Mechanical coupling means having fibre to fibre mating means
- G02B6/3807—Dismountable connectors, i.e. comprising plugs
- G02B6/3833—Details of mounting fibres in ferrules; Assembly methods; Manufacture
- G02B6/3845—Details of mounting fibres in ferrules; Assembly methods; Manufacture ferrules comprising functional elements, e.g. filters
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Mechanical Coupling Of Light Guides (AREA)
Abstract
An optical fibre connector terminating device comprises a body part connectible to one part of a separate optical fibre connector (PC connector) whereby a ferrule-terminated optical fibre of the device becomes mated with an opposed end of the optical fibre of the separate connector. A length of clad optical fibre (14) which is located within the body part (11) and which is fully optically compatible with the optical fibre of the separate connector is retroverted at least once (16, 17) between the ferrule terminated end (14) and the free end of the length of fibre (15) in order to at least substantially attenuate light entering the terminated end of the length of fibre and thereby prevent back reflections from the device.
Description
IMPROVEMENTS RELATING TO OPTICAL FIBRE CONNECTING SYSTEMS
This invention relates to optical fibre connecting systems and relates more specifically to an optical fibre connector terminating device for reducing back reflections therefrom.
One specific application for the device of the present invention resides in providing an optically matched thermally stable terminating device for use in test apparatus for determining the reflectivity of optical fibre connectors. Such test apparatus has hitherto comprised a laser light source from which light is transmitted through a directional coupler via an optical fibre to one side of a test coupler connector adapted for receiving an optical fibre connector to be tested for reflectivity. The connector under test may be connected by a length of optical fibre to another connector which is optically matched. In order to measure the reflectivity of the aforesaid connector under test the light reflected back to the directional coupler is fed into a detector.As will be appreciated, the actual reflectivity of the connector under test can only be accurately determined if the connectorised far end of the length of optical fibre is properly index matched by placing the fibre end into a gel or liquid having a matching refractive index. However, changes in temperature produce inaccuracies in such reflectivity measurements since the temperature stability of these matching gels or liquids is not good and, moreover, such gels may be difficult to remove from the fibre end.
According to the present invention there is provided an optical fibre connector terminating device comprising a body part connectible to one part of a separate optical fibre connector (PC connector) whereby a ferrule-terminated optical fibre of the device becomes mated with an opposed end of the optical fibre of the separate connector, and a length of clad optical fibre located within the body part which is fully optically compatible with the optical fibre of the separate connector and which is retroverted at least once between the ferrule terminated end and the free end of the length of fibre in order to at least substantially attenuate light entering the terminated end of the length of fibre and thereby prevent back reflections from the device.
The bend (s) in the retroverted portion (s) of the optical fibre serve to attenuate the light being transmitted through the terminating device by refraction of light through the fibre cladding before such light reaches the free end of the fibre.
However, the free end of the length of optical fibre of the device is preferably provided with an angled polished surface (e.g. 150 relative to the normal to the axis of the optical fibre) so that any light which does reach the end of the fibre will be reflected therefrom and refracted into and absorbed by the cladding of the fibre.
The terminating device of the invention may advantageously be used, for example, in the previously mentioned application of connector reflectivity testing, as by connecting the device to the connector which is itself connected by optical fibre to the connector under test.
The quality of spherical surface at the ferrule terminated end of the fibre should be of at least as high as that of the corresponding surface of the connector to which it is connected.
By way of example the present invention will now be described with reference to the accompany drawing in which:
Figure 1 shows an optical fibre system for measuring the reflectivity of an optical connector; and,
Figure 2 shows a diagrammatic representation of an optical fibre connector terminating device according to the invention.
Referring to Figure 1 of the drawing, the optical reflectivity measuring system illustrated comprises a laser 1 the light output from which is fed to a directional coupler 2 through a clad optical fibre 3. The output from the coupler 2 is then fed via a further optical fibre 4 to a connector/coupler 5 which is adapted to receive a socalled PC (physical contact) optical fibre connector 6 to be tested for optical reflectivity. Any light reflected from the characteristic spherical end surface of the PC connector 6 is arranged to be measured by a detector 7 after passing back through the optical fibre 4 and then through the coupler 2 and an optical fibre 7 to an optical detector 8.
One of the problems with such a measuring system is that light entering the optical connector 6 and an output clad optical fibre 9 and a further separate connector 10 can be reflected to varying degrees back along the clad fibre 9 to the connector 6 under test unless the end of the optical fibre is properly indexed matched. Hitherto, such refractive index matching has been achieved by locating the free end of the optical fibre 9 in a gel or liquid having a matching refractive index but nevertheless changes in temperature affecting the thermal compatibility and refractive indexes of the optical fibre/gel produce inaccuracies in the connector reflectivity measurements taken.
Referring now to Figure 2 of the drawing, this shows an optical fibre connector terminating device effective for providing a thermally compatible and matched load in the testing application illustrated in Figure 1. The device which may, for example, be connected to the connector 10 in
Figure 1 comprises a cylindrical metal body part 11 having a serrated outer slidable sleeve 12. Projecting from the right hand end of the device is a ferrule 13 of ceramic or other suitable material in which is terminated, by bonding, the end of a length of clad optical fibre 14 having a refractive index matched to that of the optical fibre 9 in the Figure 1 testing system. The terminated end of the optical fibre 14 has the characteristic spherical surface of a so-called PC connector.Between the ferrule terminated end of the optical fibre and the far end of the length of optical fibre 15 the fibre is retroverted, as shown in dotted outline, to provide two 1800 bends 16 and 17 the radius of which is such as to provide maximum attenuation of light travelling along the fibre from the ferrule terminated end thereof. However, in order to remove by refraction into the fibre cladding any light which may possibly reach the free end of the fibre 15, the fibre is provided with a polished angle end surface 16 the angle of which may be upwards of 5 , but preferably about 150, relative to the normal to the optical fibre axis.
As will be appreciated from the foregoing, when the terminated device of the invention is connected to the connector 10 in Figure 1, any light which is received by the device over the optical fibre 9 will be absorbed by the device so that no light will be reflected back along the optical fibre 9 to the connector 6 under test, irrespective of any temperature changes that may occur during testing.
Hence, the true reflectivity of the connector 9 can be measured by the detector 8.
Although the device especially suitable for optical fibre connecting testing applications as described above, it will be understood that the terminating device of the invention could also be used to prevent back reflections from connectors in operational optical fibre systems.
Claims (6)
1. An optical fibre connector terminating device comprising a body part connectible to one part of a separate optical fibre connector (e.g. PC connector) whereby a ferrule-terminated optical fibre of the device becomes mated with an opposed end of the optical fibre of the separate connector, and a length of clad optical fibre located within the body part which is fully compatible with the optical fibre of the separate connector and which is retroverted at least once between the ferrule-terminated end and the free end of the length of fibre in order to at least substantially attenuate light entering the terminated end of the length of fibre and thereby prevent back reflections along the fibre of the device.
2. An optical fibre terminating device as claimed in claim 1, in which the length of optical fibre is provided with two bends of 1800.
3. An optical fibre terminating device as claimed in claim 1 or claim 2, in which the end of the length of optical fibre remote from the ferrule terminated end is provided with an angled polished surface from which light propagating along the fibre will be reflected at such an angle as to cause reflection thereof and refraction into the fibre cladding.
4. An optical fibre terminating device as claimed in claim 3, in which the angle of the angled polished surface relative to the normal to the fibre axis is 150.
5. An optical fibre terminating device as claimed in any preceding claim for use in terminating an optical fibre
PC connector being tested for reflectivity, in which the refractive index of the length of fibre is matched to that of the optical connector and in which the spherical surface of the ferrule-terminated end of the length of fibre is at least as high a quality as that of the corresponding surface of the optical fibre terminating in the connector to which the connector under test is connected.
6. An optical fibre terminating device substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9123705A GB2261524A (en) | 1991-11-07 | 1991-11-07 | Optical fibre connecting system |
| PCT/GB1992/001840 WO1993009452A1 (en) | 1991-11-07 | 1992-10-09 | Improvements relating to optical fibre connecting systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9123705A GB2261524A (en) | 1991-11-07 | 1991-11-07 | Optical fibre connecting system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9123705D0 GB9123705D0 (en) | 1992-01-02 |
| GB2261524A true GB2261524A (en) | 1993-05-19 |
Family
ID=10704272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9123705A Withdrawn GB2261524A (en) | 1991-11-07 | 1991-11-07 | Optical fibre connecting system |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2261524A (en) |
| WO (1) | WO1993009452A1 (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4124364A (en) * | 1976-12-02 | 1978-11-07 | International Standard Electric Corporation | Method for making glass sleeve fiber splice |
| GB2025650A (en) * | 1978-07-18 | 1980-01-23 | Standard Telephones Cables Ltd | Fibre-optic cable joints |
| US4264127A (en) * | 1979-04-04 | 1981-04-28 | Amp Incorporated | Optical detector assembly and method |
| EP0032466A1 (en) * | 1980-01-11 | 1981-07-22 | COMMISSARIAT A L'ENERGIE ATOMIQUE Etablissement de Caractère Scientifique Technique et Industriel | Connector for optical fibres |
| GB2098354A (en) * | 1981-05-12 | 1982-11-17 | Philips Nv | Connector for coupling at least one optical fibre to a further optical element |
| GB2154333A (en) * | 1984-01-25 | 1985-09-04 | Int Standard Electric Corp | Connector coupling for optical waveguides |
| EP0258964A2 (en) * | 1986-07-21 | 1988-03-09 | AT&T Corp. | Connector for optical fiber cable |
| US4978193A (en) * | 1989-08-24 | 1990-12-18 | Raychem Corporation | Optical fiber connector which provides a high signal return loss |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8328575D0 (en) * | 1983-10-26 | 1983-11-30 | Plessey Co Plc | Optical fibre attenuator |
| US4998795A (en) * | 1989-05-12 | 1991-03-12 | Amp Incorporated | Reflection-less terminator |
| US5058983A (en) * | 1990-07-06 | 1991-10-22 | Aster Corporation | Fiber optic connector terminator |
-
1991
- 1991-11-07 GB GB9123705A patent/GB2261524A/en not_active Withdrawn
-
1992
- 1992-10-09 WO PCT/GB1992/001840 patent/WO1993009452A1/en active Application Filing
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4124364A (en) * | 1976-12-02 | 1978-11-07 | International Standard Electric Corporation | Method for making glass sleeve fiber splice |
| GB2025650A (en) * | 1978-07-18 | 1980-01-23 | Standard Telephones Cables Ltd | Fibre-optic cable joints |
| US4264127A (en) * | 1979-04-04 | 1981-04-28 | Amp Incorporated | Optical detector assembly and method |
| EP0032466A1 (en) * | 1980-01-11 | 1981-07-22 | COMMISSARIAT A L'ENERGIE ATOMIQUE Etablissement de Caractère Scientifique Technique et Industriel | Connector for optical fibres |
| GB2098354A (en) * | 1981-05-12 | 1982-11-17 | Philips Nv | Connector for coupling at least one optical fibre to a further optical element |
| GB2154333A (en) * | 1984-01-25 | 1985-09-04 | Int Standard Electric Corp | Connector coupling for optical waveguides |
| EP0258964A2 (en) * | 1986-07-21 | 1988-03-09 | AT&T Corp. | Connector for optical fiber cable |
| US4978193A (en) * | 1989-08-24 | 1990-12-18 | Raychem Corporation | Optical fiber connector which provides a high signal return loss |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9123705D0 (en) | 1992-01-02 |
| WO1993009452A1 (en) | 1993-05-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |