CA1242889A - Method of manufacturing optical fibres - Google Patents
Method of manufacturing optical fibresInfo
- Publication number
- CA1242889A CA1242889A CA000458634A CA458634A CA1242889A CA 1242889 A CA1242889 A CA 1242889A CA 000458634 A CA000458634 A CA 000458634A CA 458634 A CA458634 A CA 458634A CA 1242889 A CA1242889 A CA 1242889A
- Authority
- CA
- Canada
- Prior art keywords
- glass tube
- glass
- plasma
- tube
- rotation
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
- C03B37/018—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
- C03B37/01807—Reactant delivery systems, e.g. reactant deposition burners
- C03B37/01815—Reactant deposition burners or deposition heating means
- C03B37/01823—Plasma deposition burners or heating means
- C03B37/0183—Plasma deposition burners or heating means for plasma within a tube substrate
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Plasma & Fusion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
ABSTRACT:
In the PCVD method, glass layers are deposited on the inner wall of a glass tube heated at a temperature between 1100 and 1300°C by passing a reactive gas mixture through the glass tube at a pressure between 1 and 30 mbar, while a plasma is reciprocated strokewise in the interior of the glass tube. The glass tube, after a sufficient number of glass layers has been deposited, is collapsed so as to form a solid preform from which optical fibres are drawn. In order to achieve cylindrically symmetrical refractive index profiles, the heated glass tube is con-tinuously rotated during the deposition of the glass layers.
The direction of rotation of the glass tube is reversed every time the direction of movement of the plasma is reversed.
In the PCVD method, glass layers are deposited on the inner wall of a glass tube heated at a temperature between 1100 and 1300°C by passing a reactive gas mixture through the glass tube at a pressure between 1 and 30 mbar, while a plasma is reciprocated strokewise in the interior of the glass tube. The glass tube, after a sufficient number of glass layers has been deposited, is collapsed so as to form a solid preform from which optical fibres are drawn. In order to achieve cylindrically symmetrical refractive index profiles, the heated glass tube is con-tinuously rotated during the deposition of the glass layers.
The direction of rotation of the glass tube is reversed every time the direction of movement of the plasma is reversed.
Description
3L~4~:8~9 PHD. 83.068 The invention relates to a method of manufact-uring optical fibres in which glass :layers are deposited on the inner wall of a glass tube heated.at a temperature between llO0 and 1300C by passing a reactive gas mixture through the glass tube a-t a pressure between l and 30 mbar while a plasma is reciprocated strokewise in the interior of the glass tube after which the glass tube, after a suf-ficient number of glass .layers has been deposited, is to col:lapse so as to form.a solid preform from which optical fibres are drawn.
"Glass tube" is to be understood to mean in this connection.a suhstrate tube or claddlng tube which consists of.amo.rphous silica wh:ich either is made synthetically or by melting quartz crys.tals (fused silica, fused quartz) which:amorphous silic.a may be doped, or which tube consists both.of synthetically made;amorphous silica:and of amor-phous silica made by melting quartz crystals (fused silica, fused quartz) which may.also be doped.
The manufacture of optical fibres, according to the.aho~e-described method is known from US Patent Speci-fications Re 30 635:and 43 14 833. This method of manufac-turing is:referred to in the.art.as "non-isothermal plasma CVD-method" (non-isothermal PCVD-method). In this method, glas.s layers.are deposited directly from the gas phase on the inner wall of the glass tube (heterogeneous reaction).
The formation of glass soot in the gas phase is avoided;
this is described in de.tail in particular in US Patent Specification 43 14 833.
Another method for -the manufacture of high-quality optical fibres is the so-called MCVD method.
The essential difference between the PCVD method .and the MCVD method.resides in the nature and-manner in which the chemical reactions necessary for the deposition PHD 83.068 -2- 14.6.1984 of the glass components are induced. Whereas the MCVD-method utilizes thermal excitations, the PCVD-method uses electron impact excitation. In the MCVD-method primarily fine dust particles (glass soot) are formed, the deposition of which in the temperature and gravity field can occur only uniformly in and on rotating substrate .In contrast herewith the formation of fine dust particles does not occur in the electron impact excitation of the PCVD-method;
the gaseous reaction products are rather present in a mole-cular form and can reach the inner wall of the normallyused SiO2-tube via a rapid diffusion and can condense there;
a sintering is not necessary afterwards. For this reason it is also possible in the PCVD-method to deposit glass in both directions of movement of the plasma. In contrast here-with in the MCVD-method only when the thermal energy source moves in the sarne direction as the reactive gases glass particles can be deposited.
It could be demonstrated ("Deposition of SiO2 with low Impurity Conten-t by oxidation of SiC14 in a non Iso-thermal Plasma" J. Koenings, D. Kippers, H.Lydtin, H. Wilson,Proceedings of the 5th Int. Conf. on CVD (1975) I. 270-280) that with -the PCVD-method in well controlled labora-tory experiments a uniform inner wall coating of a station-ary tube is possible, i.e. the extremely small influence of gravity In atomic and molecular speciesmay be neglected.
On transfer of the laboratory data to pilot and production equipments, however, certain -types of profile imperfections which in particular showed no cylinder symmetry occurred in the manufactured fibres. It is clear that the bandwidth value of such fibres should be far below the theroretically possible value. Although said profile imperfections accord-ing to the known PCVD methods with stationary cladding tube can principally be avoided this requires a comparatively high expenditure of apparatuses For example, the deposition behaviour of the index-varying doping material and hence the shape of the refractive index profile depend on the temperature (P.Bach-mann, P. Geittner, H. Wilson, Proc. of the 8th ECOC-Confe-..
., .
~2a~
PHD 83.068 -3- 14.6.1984 rence, Cannes, ~.516 (1982). Non-uniform temperature dis-tributions over the circumference of the tube during the deposition automatically lead to peripheral profile imper-fections. A non-uniform temperature distribution can be caused inter alia by convection currents and inhomogeneous heat dissipation over the circumference of the furnaces used for heating the tube. In order -to achieve a uniform temperature distribution, a high expenditure of apparatuses would generally be necessary.
The energy distribution in the plasma can in practice also be asymmetric - for example via a non-centric arrangement of the tube in the microwave resonator - which also produces deposition asymmetries. Furthermore in the known PCVD me-thod a hardly noticeable bending of the tube occurs, which involves difficulties upon collapsing.
Such non-centric arrangements and the bending could be avoided by positioning -the tube very exactly in the reso-nator and suppor-ting the tube during the whole deposition.
However, this would further complicate the technical invest-ment of apparatuses as well as the problems regarding tem-pera-ture distribution.
It is the object of -the inven-tion to avoid the formation of peripheral radial and axial profile imperfec-tions in PCVD optical fibres in a simple manner According to -the invention this object is achiev-ed in -that in a method of the type mentioned in the opening paragraph the heated glass tube is continuously rotated during the deposition of the glass layers and the direct-ion of rotation is reversed every time the direction of movemen-t of the plasma is reversed.
The glass tube at each reversal of the direction Y of movement of the plasma at the same time is rotated over ,, an ~6~e smaller than or equal to 180 around its longitu-dinal axis. The result thereof is that failures caused by an asymmetrical energy distribution in the plasma are com-pensated.
Advantageously, the rotation is carried out at at least 0.25 rotations per s-troke. At smaller rotation 8~
- PHD 83.068 -4- 14.6.1984 veloci-ties a compensation of a non-uniform temperature distribution would hardly occur. The upper limit of the rotation velocity is limited substantially only by the performance of the necessarily required vacuum-tight ro-tating lead-throughs.
The effect of the measures according to the in-vention used separately or in combination is substan-tially based on the fact that peripheral imperfections built in in radial and/or axial direction during the deposition of lD successive individual layers are varied as completely as possible in their relative position with respect to each o-ther and in such a manner that such imperfections over the deposition length compensate each other.
As already stated, rotation is carried out in the MCVD-method continuously so as to eliminate the effects of gravity. In the PCVD me-thod on the contrary, difficul-ties of a different nature are introduced with a continuous rotation in fact imperfections would not be compensated at certain points along the deposition length.
The disturbing effects of non-uniform tempera-ture distributions are removed in a simple manner by the way of rota-tion according -to -the invention, since herewith the temperature on the circumference of the tube can be uniformly adjusted to an average value due to the thermal inertia of the -tube.
All in all it could not be expected that all these manifold problems could be obviated by the comparatively simple way of rotation according to the invention.
As already mentioned hereinbefore, refractive index profiles which are subs-tantially free from peripheral radial and axial dis-turbances can also be achieved by means of the PCVD-method without rotation. However, higher order disturbing effects can be obviated in a simple manner by the method according to the invention, i.e. improvements in the miniature structure of the optical fibres are achiev-ed. These improvements are desirable in particular to achieve bandwidths over 1 GHz.km.
The invention will be described in greater detail
"Glass tube" is to be understood to mean in this connection.a suhstrate tube or claddlng tube which consists of.amo.rphous silica wh:ich either is made synthetically or by melting quartz crys.tals (fused silica, fused quartz) which:amorphous silic.a may be doped, or which tube consists both.of synthetically made;amorphous silica:and of amor-phous silica made by melting quartz crystals (fused silica, fused quartz) which may.also be doped.
The manufacture of optical fibres, according to the.aho~e-described method is known from US Patent Speci-fications Re 30 635:and 43 14 833. This method of manufac-turing is:referred to in the.art.as "non-isothermal plasma CVD-method" (non-isothermal PCVD-method). In this method, glas.s layers.are deposited directly from the gas phase on the inner wall of the glass tube (heterogeneous reaction).
The formation of glass soot in the gas phase is avoided;
this is described in de.tail in particular in US Patent Specification 43 14 833.
Another method for -the manufacture of high-quality optical fibres is the so-called MCVD method.
The essential difference between the PCVD method .and the MCVD method.resides in the nature and-manner in which the chemical reactions necessary for the deposition PHD 83.068 -2- 14.6.1984 of the glass components are induced. Whereas the MCVD-method utilizes thermal excitations, the PCVD-method uses electron impact excitation. In the MCVD-method primarily fine dust particles (glass soot) are formed, the deposition of which in the temperature and gravity field can occur only uniformly in and on rotating substrate .In contrast herewith the formation of fine dust particles does not occur in the electron impact excitation of the PCVD-method;
the gaseous reaction products are rather present in a mole-cular form and can reach the inner wall of the normallyused SiO2-tube via a rapid diffusion and can condense there;
a sintering is not necessary afterwards. For this reason it is also possible in the PCVD-method to deposit glass in both directions of movement of the plasma. In contrast here-with in the MCVD-method only when the thermal energy source moves in the sarne direction as the reactive gases glass particles can be deposited.
It could be demonstrated ("Deposition of SiO2 with low Impurity Conten-t by oxidation of SiC14 in a non Iso-thermal Plasma" J. Koenings, D. Kippers, H.Lydtin, H. Wilson,Proceedings of the 5th Int. Conf. on CVD (1975) I. 270-280) that with -the PCVD-method in well controlled labora-tory experiments a uniform inner wall coating of a station-ary tube is possible, i.e. the extremely small influence of gravity In atomic and molecular speciesmay be neglected.
On transfer of the laboratory data to pilot and production equipments, however, certain -types of profile imperfections which in particular showed no cylinder symmetry occurred in the manufactured fibres. It is clear that the bandwidth value of such fibres should be far below the theroretically possible value. Although said profile imperfections accord-ing to the known PCVD methods with stationary cladding tube can principally be avoided this requires a comparatively high expenditure of apparatuses For example, the deposition behaviour of the index-varying doping material and hence the shape of the refractive index profile depend on the temperature (P.Bach-mann, P. Geittner, H. Wilson, Proc. of the 8th ECOC-Confe-..
., .
~2a~
PHD 83.068 -3- 14.6.1984 rence, Cannes, ~.516 (1982). Non-uniform temperature dis-tributions over the circumference of the tube during the deposition automatically lead to peripheral profile imper-fections. A non-uniform temperature distribution can be caused inter alia by convection currents and inhomogeneous heat dissipation over the circumference of the furnaces used for heating the tube. In order -to achieve a uniform temperature distribution, a high expenditure of apparatuses would generally be necessary.
The energy distribution in the plasma can in practice also be asymmetric - for example via a non-centric arrangement of the tube in the microwave resonator - which also produces deposition asymmetries. Furthermore in the known PCVD me-thod a hardly noticeable bending of the tube occurs, which involves difficulties upon collapsing.
Such non-centric arrangements and the bending could be avoided by positioning -the tube very exactly in the reso-nator and suppor-ting the tube during the whole deposition.
However, this would further complicate the technical invest-ment of apparatuses as well as the problems regarding tem-pera-ture distribution.
It is the object of -the inven-tion to avoid the formation of peripheral radial and axial profile imperfec-tions in PCVD optical fibres in a simple manner According to -the invention this object is achiev-ed in -that in a method of the type mentioned in the opening paragraph the heated glass tube is continuously rotated during the deposition of the glass layers and the direct-ion of rotation is reversed every time the direction of movemen-t of the plasma is reversed.
The glass tube at each reversal of the direction Y of movement of the plasma at the same time is rotated over ,, an ~6~e smaller than or equal to 180 around its longitu-dinal axis. The result thereof is that failures caused by an asymmetrical energy distribution in the plasma are com-pensated.
Advantageously, the rotation is carried out at at least 0.25 rotations per s-troke. At smaller rotation 8~
- PHD 83.068 -4- 14.6.1984 veloci-ties a compensation of a non-uniform temperature distribution would hardly occur. The upper limit of the rotation velocity is limited substantially only by the performance of the necessarily required vacuum-tight ro-tating lead-throughs.
The effect of the measures according to the in-vention used separately or in combination is substan-tially based on the fact that peripheral imperfections built in in radial and/or axial direction during the deposition of lD successive individual layers are varied as completely as possible in their relative position with respect to each o-ther and in such a manner that such imperfections over the deposition length compensate each other.
As already stated, rotation is carried out in the MCVD-method continuously so as to eliminate the effects of gravity. In the PCVD me-thod on the contrary, difficul-ties of a different nature are introduced with a continuous rotation in fact imperfections would not be compensated at certain points along the deposition length.
The disturbing effects of non-uniform tempera-ture distributions are removed in a simple manner by the way of rota-tion according -to -the invention, since herewith the temperature on the circumference of the tube can be uniformly adjusted to an average value due to the thermal inertia of the -tube.
All in all it could not be expected that all these manifold problems could be obviated by the comparatively simple way of rotation according to the invention.
As already mentioned hereinbefore, refractive index profiles which are subs-tantially free from peripheral radial and axial dis-turbances can also be achieved by means of the PCVD-method without rotation. However, higher order disturbing effects can be obviated in a simple manner by the method according to the invention, i.e. improvements in the miniature structure of the optical fibres are achiev-ed. These improvements are desirable in particular to achieve bandwidths over 1 GHz.km.
The invention will be described in greater detail
2~
PHD 83-068 -5- 1~.6.1g84 with reference to a drawing and a comparative example.
In the drawing ig. 1 shows an optimum parabolic refractive index profile manufactured according to the PCVD method without rotation and Fig. 2 shows a refractive index profile manufac-tured according to the PCVD method according to the inven-tion.
In both figures the variation of the refractive index dependent on the radius of` the preform is shown.
In the first part of the example it was tried to produce an optimum parabolic refractive index profile in the core of a preform according to the PCVD method without rotation. The deposition of the material occurred under the following experimental conditions:
SiO2-substrate tube having an inside diameter of 15.0 mm and an outside diameter of 18.0 mm was used.
The length of deposition was adjusted at approximately 45 cm. The average pressure in the deposition area was approximately 15 mbar, the wall temperature of the sub-strate tube was approximately 1150 to 1250C. A microwave resonator having a power consumption of 500 W was recipro-cated over the desposi-tion area at a rate of 8 m/min. The overall gas flow was kept constant at 800 sccm (= cm3 of gas per minute under normal conditions: 0 C, I bar) during the whole deposition lasting approximately 120 minutes;
so the overall number of layers was 2100.
The reaction gas flows Q during deposition were supplied as follows: the oxygen flow remained constant at Qo2 = 7 sccm. In the op-tical cladding area the SiCl4 and GeC14 flows were kept constant at QSiCl = 110 sccm and QGeCl = 0 sccm; in the core area, QSiCl4 110 to 100 sccm and QGecl was varied from 0 to 18 sccm so that (with an approximately constant chloride gas flow of approximately 110 to 120 sccm) a parabolic refractive index profile was achieved. The deposition rate for the doped core material in the present conditions was approxi-... .
PHD 83-068 -6- 14.6.1984 mately 0.30 to 0.35 g/min.
Fig. 1 shows the refractive index profile thus obtained in the collapsed preform (York Technology, P101-Analyzer-Plot, Position 300 mma O degree; 961 points in 10 /um steps). As is clearly seen, -the profile in particu-lar in the proximity of the centre - beside the central dip-shows a pronounced asymmetry A of approximately Z /0 (re-lated to the average refractive index difference in the centre), which impedes the adjustmen-t of higher bandwidths and hence is undesired. The bandwidth ox the fibre drawn from the preform in the present example was 800 MHz.km (with a transmission wavelength of 900 nm). Further a geometrical asymmetry of approximately + 1.5 % is found.
In the second part of the example a further pre-lS form was manufactured with identical deposition conditionsin which this time, however, the substrate tube was rotated during the deposition. The rotation of the tube was made possible by means of two rotation leadthroughs which were substantially gas-tight (leakage rates in the range from 10 4 to 10 5 mbar.l.s 1) and were driven synchronously.
In the present example the rotation frequency was 25 rpm which, with the adjus-ted stroke frequency of approxima-tely 16,6 strokes/min. (coating length 45 cm with a resonator speed of 8 m/min) corresponds to 1.5 ro-tations per layer.
The angle rotation at each reversal of the direction of plasma movement was 180 ; at the same time the direction of rotation was reversed.
Fig. 2 shows the absolutely rotationally symme-trical refractive index profile of the preform resulting in this case (measuring conditions as in fig. 1). The band-width of the fibre drawn from said preform was approximate-ly 1600 MHz.km at 900 nm, so was approximately double as high as in the case of the first part of the example with-out rotation during the coating. Optical and geometrical asymmetries amount to approximately a few tenths of a percent.
PHD 83-068 -5- 1~.6.1g84 with reference to a drawing and a comparative example.
In the drawing ig. 1 shows an optimum parabolic refractive index profile manufactured according to the PCVD method without rotation and Fig. 2 shows a refractive index profile manufac-tured according to the PCVD method according to the inven-tion.
In both figures the variation of the refractive index dependent on the radius of` the preform is shown.
In the first part of the example it was tried to produce an optimum parabolic refractive index profile in the core of a preform according to the PCVD method without rotation. The deposition of the material occurred under the following experimental conditions:
SiO2-substrate tube having an inside diameter of 15.0 mm and an outside diameter of 18.0 mm was used.
The length of deposition was adjusted at approximately 45 cm. The average pressure in the deposition area was approximately 15 mbar, the wall temperature of the sub-strate tube was approximately 1150 to 1250C. A microwave resonator having a power consumption of 500 W was recipro-cated over the desposi-tion area at a rate of 8 m/min. The overall gas flow was kept constant at 800 sccm (= cm3 of gas per minute under normal conditions: 0 C, I bar) during the whole deposition lasting approximately 120 minutes;
so the overall number of layers was 2100.
The reaction gas flows Q during deposition were supplied as follows: the oxygen flow remained constant at Qo2 = 7 sccm. In the op-tical cladding area the SiCl4 and GeC14 flows were kept constant at QSiCl = 110 sccm and QGeCl = 0 sccm; in the core area, QSiCl4 110 to 100 sccm and QGecl was varied from 0 to 18 sccm so that (with an approximately constant chloride gas flow of approximately 110 to 120 sccm) a parabolic refractive index profile was achieved. The deposition rate for the doped core material in the present conditions was approxi-... .
PHD 83-068 -6- 14.6.1984 mately 0.30 to 0.35 g/min.
Fig. 1 shows the refractive index profile thus obtained in the collapsed preform (York Technology, P101-Analyzer-Plot, Position 300 mma O degree; 961 points in 10 /um steps). As is clearly seen, -the profile in particu-lar in the proximity of the centre - beside the central dip-shows a pronounced asymmetry A of approximately Z /0 (re-lated to the average refractive index difference in the centre), which impedes the adjustmen-t of higher bandwidths and hence is undesired. The bandwidth ox the fibre drawn from the preform in the present example was 800 MHz.km (with a transmission wavelength of 900 nm). Further a geometrical asymmetry of approximately + 1.5 % is found.
In the second part of the example a further pre-lS form was manufactured with identical deposition conditionsin which this time, however, the substrate tube was rotated during the deposition. The rotation of the tube was made possible by means of two rotation leadthroughs which were substantially gas-tight (leakage rates in the range from 10 4 to 10 5 mbar.l.s 1) and were driven synchronously.
In the present example the rotation frequency was 25 rpm which, with the adjus-ted stroke frequency of approxima-tely 16,6 strokes/min. (coating length 45 cm with a resonator speed of 8 m/min) corresponds to 1.5 ro-tations per layer.
The angle rotation at each reversal of the direction of plasma movement was 180 ; at the same time the direction of rotation was reversed.
Fig. 2 shows the absolutely rotationally symme-trical refractive index profile of the preform resulting in this case (measuring conditions as in fig. 1). The band-width of the fibre drawn from said preform was approximate-ly 1600 MHz.km at 900 nm, so was approximately double as high as in the case of the first part of the example with-out rotation during the coating. Optical and geometrical asymmetries amount to approximately a few tenths of a percent.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacturing optical fibres in which glass layers are deposited on the inner wall of a glass tube heated at a temperature between 1100 and 1300°C by passing a reactive gas mixture through the glass tube at a pressure between 1 and 30 mbar, while a plasma is reciprocated strokewise in the interior of the glass tube, after which the glass tube, after a sufficient number of glass layers has been deposited, is collapsed so as to form a solid preform from which optical fibres are drawn, characterized in that the heated glass tube is continuously rotated during the deposition of the glass layers and the direction of rotation is reversed every time the direction of movement of the plasma is reversed.
2. A method as claimed in Claim 1, characterized in that the glass tube at each reversal of the direction of movement of the plasma at the same -time is rotated over an angle smaller than or equal to 180° around its longitu-dinal axis.
3. A method as claimed in Claim 1 or 2, character-ized in that the rotation of the glass tube is carried out at at least 0.25 revolutions per stroke.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3325700.0 | 1983-07-16 | ||
| DE3325700 | 1983-07-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1242889A true CA1242889A (en) | 1988-10-11 |
Family
ID=6204142
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000458634A Expired CA1242889A (en) | 1983-07-16 | 1984-07-11 | Method of manufacturing optical fibres |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0132011B1 (en) |
| JP (1) | JPS6036344A (en) |
| CA (1) | CA1242889A (en) |
| DE (1) | DE3481508D1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3445239A1 (en) * | 1984-12-12 | 1986-06-19 | Philips Patentverwaltung Gmbh, 2000 Hamburg | METHOD FOR THE PRODUCTION OF OPTICAL FIBERS |
| JPS61222936A (en) * | 1985-03-27 | 1986-10-03 | Furukawa Electric Co Ltd:The | Plasma cvd process |
| DE3635034A1 (en) * | 1986-10-15 | 1988-04-21 | Philips Patentverwaltung | METHOD FOR THE PRODUCTION OF OPTICAL FIBERS |
| DE3720030A1 (en) * | 1987-06-16 | 1988-12-29 | Philips Patentverwaltung | METHOD FOR THE PRODUCTION OF OPTICAL FIBERS |
| JP2549654Y2 (en) * | 1991-10-09 | 1997-09-30 | 株式会社小松製作所 | Movable backing device |
| GB2286199B (en) * | 1994-01-27 | 1997-06-11 | Pirelli General Plc | A method of forming an optical fibre preform |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2444100C3 (en) * | 1974-09-14 | 1979-04-12 | Philips Patentverwaltung Gmbh, 2000 Hamburg | Process for the production of internally coated glass tubes for drawing optical fibers |
| DE2907731A1 (en) * | 1979-02-28 | 1980-09-04 | Siemens Ag | METHOD FOR PRODUCING A FIBERGLASS FIBER |
| DE2907833A1 (en) * | 1979-02-28 | 1980-09-11 | Siemens Ag | METHOD FOR PRODUCING COATED GLASS BODIES |
| DE2929166A1 (en) * | 1979-07-19 | 1981-01-29 | Philips Patentverwaltung | METHOD FOR THE PRODUCTION OF OPTICAL FIBERS |
| NL8302127A (en) * | 1983-06-15 | 1985-01-02 | Philips Nv | METHOD AND APPARATUS FOR THE MANUFACTURE OF OPTICAL FIBERS |
-
1984
- 1984-07-11 CA CA000458634A patent/CA1242889A/en not_active Expired
- 1984-07-11 EP EP84201022A patent/EP0132011B1/en not_active Expired - Lifetime
- 1984-07-11 DE DE8484201022T patent/DE3481508D1/en not_active Expired - Lifetime
- 1984-07-13 JP JP59144571A patent/JPS6036344A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| EP0132011A3 (en) | 1987-08-19 |
| DE3481508D1 (en) | 1990-04-12 |
| EP0132011A2 (en) | 1985-01-23 |
| JPH0425215B2 (en) | 1992-04-30 |
| JPS6036344A (en) | 1985-02-25 |
| EP0132011B1 (en) | 1990-03-07 |
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