CA2055772A1 - Heat-resistant optical moldings, and a process for their production - Google Patents
Heat-resistant optical moldings, and a process for their productionInfo
- Publication number
- CA2055772A1 CA2055772A1 CA002055772A CA2055772A CA2055772A1 CA 2055772 A1 CA2055772 A1 CA 2055772A1 CA 002055772 A CA002055772 A CA 002055772A CA 2055772 A CA2055772 A CA 2055772A CA 2055772 A1 CA2055772 A1 CA 2055772A1
- Authority
- CA
- Canada
- Prior art keywords
- optical
- weight
- moldings
- range
- molding
- 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.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
- G02B1/045—Light guides
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/04—Coating
Abstract
ABSTRACT OF THE DISCLOSURE:
Heat-resistant optical moldings, and a process for their production A process for the production of optical moldings from polysilazanes or polyhydridochlorosilazanes in which the polysilazanes or polyhydridochlorosilazanes are pressed to give moldings or dissolved in a solvent and extruded and are subsequently exposed to a gas atmosphere at a temperature in the range from 10 to 200°C and a relative humidity in the range from 20 to 100% for from 0.1 to 24 hours.
The moldings have a core/cladding structure, the cladding comprising from 1 to 3% by weight of O, from 20 to 25% by weight of N and from 30 to 40% by weight of Si, and the core comprising 100% by weight of a polysilazane or poly-hydridochlorosilazane.
Heat-resistant optical moldings, and a process for their production A process for the production of optical moldings from polysilazanes or polyhydridochlorosilazanes in which the polysilazanes or polyhydridochlorosilazanes are pressed to give moldings or dissolved in a solvent and extruded and are subsequently exposed to a gas atmosphere at a temperature in the range from 10 to 200°C and a relative humidity in the range from 20 to 100% for from 0.1 to 24 hours.
The moldings have a core/cladding structure, the cladding comprising from 1 to 3% by weight of O, from 20 to 25% by weight of N and from 30 to 40% by weight of Si, and the core comprising 100% by weight of a polysilazane or poly-hydridochlorosilazane.
Description
7~
HOECHST AKTIENGESELLSCHAFT HOE 90/F345 DCh.5~AP
Description Heat-resistant optical moldings, and a process for ~heir production Optical fibers are widely used in ~he automotive and illumination sectors and in medical diagnostics and in particular in data transmission.
These fibers have usually been produced from glass, but the range of applications is limited to a relatively small number of certain applications due to their low flexibilit~, in particular at xelatively large diameters, and due to their low breaking strength under mechanical load.
Thers has therefore been no lack of attempts to replace glass by organic polymeric materials. Polymer fibers have low specific gravity, but nonetheless high strength.
Their flexibility is retained even at relatively large fiber diameters, and they are, furthermore, virtually insensitive to mechanical load. A further advantage of polymer fibers is that the ~tarting components ar~
inexpensive and easy to produce. However, the trans-mission of optical fibers made from organic polymers drops considerably as the temperature is increased, which means that their use is limited to areas in which they are not subjected to considerable heating. Thus, for example, the maximum service temperature of polymethyl methacrylate is 80~C.
In general, a polymeric optical fiber comprises a core of relatively high refractive index and a cladding of lower refractive index. This arrangement ensures that the light does not leave the fiber due to reflection at the core/
cladding interface and thu~ remainR within the fiber. In the case of optical fibers ~or light, it is therefore ~ 2 ~ 7~
necessary to apply a layer which entirely surrounds the fiber. The application of layers of this type, for example by dipping the fi~er into a solution containing a polymer in dissolved form or by special spinning processes r i5 expensive and complicated.
The ob~ect was therefore to provide optical moldings, in particular having a core/cladding structure, which can be obtained by a simple and economical proce~s, have high flexibility, high brsaking s~rength and good transmission and, in particular, can be used even at elevated temperatures.
The present invention solves this ob~ect. It has been found that fibers having a core/cladding s~ructure and the abovementioned advantages can be obtained from polymeric silazanes or hydridochlorosilazanes.
Such polysilazanes and polyhydridochlorosilazanes which are suitable for the production of the molding~ according to the invention were hitherto only used as precer~nic materials which are pyrolized to give silicon nitride and are described, for example, in DE-A-37 37 921 (US-A~4,935,481), DE-A-37 43 825 (US-A-4,939,225), US-A-4,946,920 and US-A-4,931,513.
~he present invention accordingly provides a process for the production of optical moldings from polysilazanes or polyhydridochlorosilazanes, which are first pressed to give moldings or dissolved in a solvent and extruded and are sub~equently exposed to a ga~ atmosphere at a tem-perature in the range from +10 to +200~C and a relative humidity in the range from 20 to 100~ for from 0.1 to 24 hours.
These polysilazaneR can be prepared, ~or ex~nple, by reacting aminochloroRilane~ (I) of the formula RSiCl2-NR-R
with 3.15 mol of ~nonia per mole of silane in THF, fo~ning oligomers of the formula (II) - 3 ~ 5~
R' R' R' R' ,~
~ N
Cl - Si - Cl + 3 n NH3 ~- Si - N~ 2 n NH4Cl (I) (II~
where n is an integer.
Elimination of the dialkyl~mino group allows further crosslinking of the oligomers with one another, giving polysilazanes containing s~ructural units of the formula S ~III) (NH)1/2 1 ~ R' R' ~- Si - N ~ Si - N; - (III) R and R' may in this case be identical or different radicals. Possible radicals R and R' are, for example, R = (Cl-C4)alkyl, vinyl or phenyl, and R' = ~Cl-C4)alkyl.
In the abovementioned formula, x and y are the molar fractions of the two structural unit~, where x + y = 1 and x can have a value in the range from 0.75 to 0.95.
Examples of other polysilazanes which can be used for the production of the moldings according to the invention are descxibed in the abovementioned publications.
To produce the moldings according to the invention, the polysilazanes are either preæsed directly into the desired shape or first dissolved in a solvent, for example THF, hexane or toluene, and ~ubsequently spun to give fibers in a piston spinning machine or extru~ion spinning machine at an atmospheric humidity of less than - 4 ~ 5~7~
1% (for example in dry nitxo~enl.
The moldings according to the invention having a core/
cladding structure are produced from poly3ilazane mold-ings in a ~ubsequent step by introducing the poly-sila2ane molding~ in~o a ga~ atmosphere having a defined water content. Diffusion of the water through the surface of the fibers cau~es breaking of the Si-NH-Si bonds.
Substitution of NH by O wi~h formation and elimination of ammonia gives siloxanes, which are likewise cro~slinked with one another. The atmosphere has a rPlative humidity in the range from 20 to 100%, preferably from 30 to 90%.
The temperature is between 10 and 200C, pxeferably in the range from 20 to 50C. ~he gas atmosphere is generally purified air, but may preferably be nitrogen or a noble gas, in particular helium, particularly prefer-ably mixtures of these gases. The siloxanessilazane ratio in the cladding layer which forms can be regulated via the moisture content of the akmosphere as a function of the temperature.
The minimum residence time of the moldings depend~ on the respective temperature:relative humidity (RH) ratio. At relatively low temperatures, a higher relative humidity is preferred. The minLmum residence tLmes are determined by measuring the optical transmis~ion of the moldings.
The time at which the transmission of the molding no longer changes to a measurable extent is referred to as the minimum residence time. The residence tIme~ are furthermore dependent on the shape of the molding and on the polysilazanes employed as starting component~. ~hey are on average about 5 hours at 50 D C ~ about 2 hours at 80C and about 0.~ hour at 110C. Through a further increase in temperature, it is possible to ~urther reduce the minimum residence times. Xn khe process according to the invention, residence times of from 0.1 to 24 hour~
resulted at temperatures in the range from 10 to 200C
and relative humidities in the range from 20 to 100%.
- 5 ~ ~ 7~
The optical moldings producQd by this process ha~e a cladding comprising from 1 to 3% by weight of O, from 20 to 25% by weight of N and from 30 to 40~ by weight of Si.
The core compri~es 100% of a polysilazane or polyhydr~do-chlorosilazane. ~h~ thi~kne~6 o~ the cladding i~ in the range from 0.1 to 5 ~m, preferably in the range from 0.2 to 2.0 ~m. The attenuation of the molding~ according to the invention i~ from 0.1 to 10 dB/cm.
The silicon-containing core/cladding moldings produced by the process according to the invention have high flexi-bility, high stability under mechanical load and good heat resi~tance up to 200C and are stable e~en under extreme wea~hering conditions. Due to their high heat resistance, they are particularly suitable for illumi-nation and data-transmission applications (optical fibers) and for optical ~ensors, in particular at locations which experience considerable heating, such as, for example, in automobiles.
Example 1:
A polymeric silazane fiber wa~ first produced under a dry nitrogen atmosphere by means of a piston spinning machine. The fiber was then stored for 48 hour~ at 25C
and a humidity of 80%, forming an optical cladding. The diameter of the fiber was 1 mm.
The transmission of the fiber was measured using a light source (HeNe laser) and a detector which was movable along the fiber and a detectox at the end of the fiber.
The two detector~ are eguipped with Ulbricht globes in order to prevent anisotropy effects. Thi~ constxuction made it possible 'co measure the attenuation of the fiber and its uniformity (center6 of scattering) (Figure 1~. A
- 6 ~ 77~
value of about 0.2 d~/cm and 633 nm was ohtained.
Example 2:
The ~easur~ment station wa~ u~ed to dekermine the dependence of the attenuation on the residence ~ime in the ga~ atmosphere. The minLmum xesidencs tLme necessary was determined as the time at which the transmission no longer changes to a measurable exten~. The re~ult for an N2 atmosphere (95~ RH) was S hours ~or 50C, 2 hours for 80~Cr and 0.2 hours for 110C for a 1 mm fiber.
Example 3:
The fiber produced in Example 1 wa~ ~tored for 2 days at 150C undex purified air and at 80~ relative humidity, Remeasurement of the at~enuakion gave no significant change in the transmission.
Example 4:
The fibers produced as described in Example 1 were cured at 100C and 2G0C under nitrogen and air. A change of less than 1% in the transmission occurred.
Example 5:
A fiber with a diameter of 0.5 mm produced in accordance with Example 1 was used as an optical sensor. To this end, the fiber was placed in the vicinity of a liyht source (halogen lamp~O The intensity of the light enter~
ing the fiber, which was proportisnal to the entire light output of the lamp, could thus be employed to stabilize the light output by means of a control circuit. The temperature in the vicinity of the fiber was above 130C.
This arrangement made it pos~ible to keep the light intensity entering the fib~r con~tant over several dayR
in an experiment for measuring vibrations by optical means.
HOECHST AKTIENGESELLSCHAFT HOE 90/F345 DCh.5~AP
Description Heat-resistant optical moldings, and a process for ~heir production Optical fibers are widely used in ~he automotive and illumination sectors and in medical diagnostics and in particular in data transmission.
These fibers have usually been produced from glass, but the range of applications is limited to a relatively small number of certain applications due to their low flexibilit~, in particular at xelatively large diameters, and due to their low breaking strength under mechanical load.
Thers has therefore been no lack of attempts to replace glass by organic polymeric materials. Polymer fibers have low specific gravity, but nonetheless high strength.
Their flexibility is retained even at relatively large fiber diameters, and they are, furthermore, virtually insensitive to mechanical load. A further advantage of polymer fibers is that the ~tarting components ar~
inexpensive and easy to produce. However, the trans-mission of optical fibers made from organic polymers drops considerably as the temperature is increased, which means that their use is limited to areas in which they are not subjected to considerable heating. Thus, for example, the maximum service temperature of polymethyl methacrylate is 80~C.
In general, a polymeric optical fiber comprises a core of relatively high refractive index and a cladding of lower refractive index. This arrangement ensures that the light does not leave the fiber due to reflection at the core/
cladding interface and thu~ remainR within the fiber. In the case of optical fibers ~or light, it is therefore ~ 2 ~ 7~
necessary to apply a layer which entirely surrounds the fiber. The application of layers of this type, for example by dipping the fi~er into a solution containing a polymer in dissolved form or by special spinning processes r i5 expensive and complicated.
The ob~ect was therefore to provide optical moldings, in particular having a core/cladding structure, which can be obtained by a simple and economical proce~s, have high flexibility, high brsaking s~rength and good transmission and, in particular, can be used even at elevated temperatures.
The present invention solves this ob~ect. It has been found that fibers having a core/cladding s~ructure and the abovementioned advantages can be obtained from polymeric silazanes or hydridochlorosilazanes.
Such polysilazanes and polyhydridochlorosilazanes which are suitable for the production of the molding~ according to the invention were hitherto only used as precer~nic materials which are pyrolized to give silicon nitride and are described, for example, in DE-A-37 37 921 (US-A~4,935,481), DE-A-37 43 825 (US-A-4,939,225), US-A-4,946,920 and US-A-4,931,513.
~he present invention accordingly provides a process for the production of optical moldings from polysilazanes or polyhydridochlorosilazanes, which are first pressed to give moldings or dissolved in a solvent and extruded and are sub~equently exposed to a ga~ atmosphere at a tem-perature in the range from +10 to +200~C and a relative humidity in the range from 20 to 100~ for from 0.1 to 24 hours.
These polysilazaneR can be prepared, ~or ex~nple, by reacting aminochloroRilane~ (I) of the formula RSiCl2-NR-R
with 3.15 mol of ~nonia per mole of silane in THF, fo~ning oligomers of the formula (II) - 3 ~ 5~
R' R' R' R' ,~
~ N
Cl - Si - Cl + 3 n NH3 ~- Si - N~ 2 n NH4Cl (I) (II~
where n is an integer.
Elimination of the dialkyl~mino group allows further crosslinking of the oligomers with one another, giving polysilazanes containing s~ructural units of the formula S ~III) (NH)1/2 1 ~ R' R' ~- Si - N ~ Si - N; - (III) R and R' may in this case be identical or different radicals. Possible radicals R and R' are, for example, R = (Cl-C4)alkyl, vinyl or phenyl, and R' = ~Cl-C4)alkyl.
In the abovementioned formula, x and y are the molar fractions of the two structural unit~, where x + y = 1 and x can have a value in the range from 0.75 to 0.95.
Examples of other polysilazanes which can be used for the production of the moldings according to the invention are descxibed in the abovementioned publications.
To produce the moldings according to the invention, the polysilazanes are either preæsed directly into the desired shape or first dissolved in a solvent, for example THF, hexane or toluene, and ~ubsequently spun to give fibers in a piston spinning machine or extru~ion spinning machine at an atmospheric humidity of less than - 4 ~ 5~7~
1% (for example in dry nitxo~enl.
The moldings according to the invention having a core/
cladding structure are produced from poly3ilazane mold-ings in a ~ubsequent step by introducing the poly-sila2ane molding~ in~o a ga~ atmosphere having a defined water content. Diffusion of the water through the surface of the fibers cau~es breaking of the Si-NH-Si bonds.
Substitution of NH by O wi~h formation and elimination of ammonia gives siloxanes, which are likewise cro~slinked with one another. The atmosphere has a rPlative humidity in the range from 20 to 100%, preferably from 30 to 90%.
The temperature is between 10 and 200C, pxeferably in the range from 20 to 50C. ~he gas atmosphere is generally purified air, but may preferably be nitrogen or a noble gas, in particular helium, particularly prefer-ably mixtures of these gases. The siloxanessilazane ratio in the cladding layer which forms can be regulated via the moisture content of the akmosphere as a function of the temperature.
The minimum residence time of the moldings depend~ on the respective temperature:relative humidity (RH) ratio. At relatively low temperatures, a higher relative humidity is preferred. The minLmum residence tLmes are determined by measuring the optical transmis~ion of the moldings.
The time at which the transmission of the molding no longer changes to a measurable extent is referred to as the minimum residence time. The residence tIme~ are furthermore dependent on the shape of the molding and on the polysilazanes employed as starting component~. ~hey are on average about 5 hours at 50 D C ~ about 2 hours at 80C and about 0.~ hour at 110C. Through a further increase in temperature, it is possible to ~urther reduce the minimum residence times. Xn khe process according to the invention, residence times of from 0.1 to 24 hour~
resulted at temperatures in the range from 10 to 200C
and relative humidities in the range from 20 to 100%.
- 5 ~ ~ 7~
The optical moldings producQd by this process ha~e a cladding comprising from 1 to 3% by weight of O, from 20 to 25% by weight of N and from 30 to 40~ by weight of Si.
The core compri~es 100% of a polysilazane or polyhydr~do-chlorosilazane. ~h~ thi~kne~6 o~ the cladding i~ in the range from 0.1 to 5 ~m, preferably in the range from 0.2 to 2.0 ~m. The attenuation of the molding~ according to the invention i~ from 0.1 to 10 dB/cm.
The silicon-containing core/cladding moldings produced by the process according to the invention have high flexi-bility, high stability under mechanical load and good heat resi~tance up to 200C and are stable e~en under extreme wea~hering conditions. Due to their high heat resistance, they are particularly suitable for illumi-nation and data-transmission applications (optical fibers) and for optical ~ensors, in particular at locations which experience considerable heating, such as, for example, in automobiles.
Example 1:
A polymeric silazane fiber wa~ first produced under a dry nitrogen atmosphere by means of a piston spinning machine. The fiber was then stored for 48 hour~ at 25C
and a humidity of 80%, forming an optical cladding. The diameter of the fiber was 1 mm.
The transmission of the fiber was measured using a light source (HeNe laser) and a detector which was movable along the fiber and a detectox at the end of the fiber.
The two detector~ are eguipped with Ulbricht globes in order to prevent anisotropy effects. Thi~ constxuction made it possible 'co measure the attenuation of the fiber and its uniformity (center6 of scattering) (Figure 1~. A
- 6 ~ 77~
value of about 0.2 d~/cm and 633 nm was ohtained.
Example 2:
The ~easur~ment station wa~ u~ed to dekermine the dependence of the attenuation on the residence ~ime in the ga~ atmosphere. The minLmum xesidencs tLme necessary was determined as the time at which the transmission no longer changes to a measurable exten~. The re~ult for an N2 atmosphere (95~ RH) was S hours ~or 50C, 2 hours for 80~Cr and 0.2 hours for 110C for a 1 mm fiber.
Example 3:
The fiber produced in Example 1 wa~ ~tored for 2 days at 150C undex purified air and at 80~ relative humidity, Remeasurement of the at~enuakion gave no significant change in the transmission.
Example 4:
The fibers produced as described in Example 1 were cured at 100C and 2G0C under nitrogen and air. A change of less than 1% in the transmission occurred.
Example 5:
A fiber with a diameter of 0.5 mm produced in accordance with Example 1 was used as an optical sensor. To this end, the fiber was placed in the vicinity of a liyht source (halogen lamp~O The intensity of the light enter~
ing the fiber, which was proportisnal to the entire light output of the lamp, could thus be employed to stabilize the light output by means of a control circuit. The temperature in the vicinity of the fiber was above 130C.
This arrangement made it pos~ible to keep the light intensity entering the fib~r con~tant over several dayR
in an experiment for measuring vibrations by optical means.
Claims (7)
1. A process for the production of optical moldings from polysilazanes or polyhydridochlorosilazanes, wherein the polysilazanes or polyhydridochloro-silazanes are pressed to give moldings or dissolved in a solvent and extruded and are subsequently exposed to a gas atmosphere at a temperature in the range from 10 to 200°C and a relative humidity in the range from 20 to 100% for from 0.1 to 24 hours.
2. The process as claimed in claim 1, wherein the gas atmosphere comprises purified air, nitrogen or a noble gas, preferably helium, or a mixture of these gases.
3. A molding produced by the process as claimed in claim 1, having a core/cladding structure.
4. An optical molding having a core/cladding structure, wherein the cladding comprises from 1 to 3% by weight of 0, from 20 to 25% by weight of N and from 30 to 40% by weight of Si, and the core comprises 100% by weight of a poly-silazane or polyhydridochlorosilazane, the thickness of the optical cladding is in the range from 0.1 to
5 µm, and the molding is heat resistant up to 200°C.
5. An optical molding as claimed in claim 3, wherein the attenuation is in the range from 0.1 to 10 dB/cm.
5. An optical molding as claimed in claim 3, wherein the attenuation is in the range from 0.1 to 10 dB/cm.
6. The use of an optical molding as claimed in claim 4 as an optical fiber.
7. The use of an optical molding as claimed in claim 4 as an optical sensor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4036644.8 | 1990-11-16 | ||
| DE4036644 | 1990-11-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2055772A1 true CA2055772A1 (en) | 1993-05-19 |
Family
ID=6418437
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002055772A Abandoned CA2055772A1 (en) | 1990-11-16 | 1991-11-18 | Heat-resistant optical moldings, and a process for their production |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0485930A1 (en) |
| JP (1) | JPH04290732A (en) |
| KR (1) | KR920009895A (en) |
| CN (1) | CN1061419A (en) |
| CA (1) | CA2055772A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101432606B1 (en) * | 2011-07-15 | 2014-08-21 | 제일모직주식회사 | Filler for filling a gap, method for preparing this and method for manufacturing semiconductor capacitor using the same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0206449A3 (en) * | 1985-06-24 | 1987-06-24 | Dow Corning Corporation | A process for preparing ceramic materials |
| US4894532A (en) * | 1988-03-28 | 1990-01-16 | Westinghouse Electric Corp. | Optical fiber sensor with light absorbing moisture-sensitive coating |
| EP0361181B1 (en) * | 1988-09-09 | 1995-03-22 | Shin-Etsu Chemical Co., Ltd. | Infusibilization of organic silazane polymers and preparation of hollow ceramic fibers |
| DE4013306A1 (en) * | 1990-04-26 | 1991-10-31 | Hoechst Ag | OPTICAL MOLDED BODIES MADE OF SILICON NITRIDE, AND METHOD FOR THE PRODUCTION THEREOF |
-
1991
- 1991-11-11 EP EP91119187A patent/EP0485930A1/en not_active Withdrawn
- 1991-11-15 KR KR1019910020340A patent/KR920009895A/en not_active Application Discontinuation
- 1991-11-15 JP JP3300761A patent/JPH04290732A/en active Pending
- 1991-11-15 CN CN91110737A patent/CN1061419A/en active Pending
- 1991-11-18 CA CA002055772A patent/CA2055772A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0485930A1 (en) | 1992-05-20 |
| CN1061419A (en) | 1992-05-27 |
| KR920009895A (en) | 1992-06-25 |
| JPH04290732A (en) | 1992-10-15 |
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