US4243298A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-strength optical preforms and fibers with thin, high-compression outer layers
Assignee: U S Holding Co Inc
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Filing: 1978-10-06
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Granted: 1981-01-06
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Expires: 1998-10-06
Abstract
Abstract High-strength optical preforms and optical fibers, particularly useful in light-wave communication systems, are fabricated by techniques producing high surface compressive forces in thin outer layers. These result in substantially increased fiber tensile strength, durability, and fiber life. High surface stresses are achieved in three-layer and four-layer preforms and fibers by employing particular combinations of core, cladding, and layer compositions, dopants, coefficients of thermal expansion, and glass transition temperatures. Various suitable manufacturing methods are disclosed using chemical vapor deposition techniques. For example, preforms may be fabricated by external deposition of layers on a drawn core-glass rod, or by internal CVD methods in which layers are sequentially deposited within hollow tubular silica substrates that are then collapsed into solid preforms by known techniques. In the internal deposition methods, preform finishing techniques are also disclosed for removing excess substrate material so as to leave a high-strength compressive layer of substantially pure silica.
Inventors
- 👤 Charles K. Kao
- 👤 Mokhtar S. Maklad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:13
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/01205; C03B37/01225; C03B37/01228; C03B37/01211; C03B37/014; C03B37/018; C03B37/02; C03B37/025; C03B37/027; G; G02; G02B; G02B6/00; G02B6/44; G02B6/4401; G02B6/4402; C03B2203/00; C03B2203/10; C03B2203/22
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
119 words
An optical light-transmitting structure having high tensile strength comprising: a solid cylindrical core of a first doped silica material; a concentric cladding layer of a second doped silica material surrounding said core; said core and layer materials being selected for good optical transmission characteristics and also for a relatively high average coefficient of thermal expansion and a relatively low average glass transition temperature; and at least one additional concentric layer of a silica material surrounding said cladding layer; the outermost layer being substantially thinner than the enclosed layers and consisting of a silica material having a relatively low coefficient of thermal expansion and a relatively high glass transition temperature as compared to those of the layer which it encloses.
Claim 2
Dependent Claim
119 words
An optical light-transmitting structure having high tensile strength comprising: a solid cylindrical core of a first doped silica material; a concentric cladding layer of a second doped silica material surrounding said core; said core and layer materials being selected for good optical transmission characteristics and also for a relatively high average coefficient of thermal expansion and a relatively low average glass transition temperature; and at least one additional concentric layer of a silica material surrounding said cladding layer; the outermost layer being substantially thinner than the enclosed layers and consisting of a silica material having a relatively low coefficient of thermal expansion and a relatively high glass transition temperature as compared to those of the layer which it encloses.
Claim 3
Dependent Claim
46 words
The optical light-transmitting structure of claim 1 wherein: said core material is a silicate glass primarily doped with GeO 2 or P 2 O 5 ; said cladding layer is a silicate glass primarily doped with boron; and said outermost layer is a fused silica glass.
Claim 4
Dependent Claim
71 words
The optical light-transmitting structure of claim 2 wherein: said core, cladding, and any intermediate layer have a weighted average coefficient of thermal expansion an order of magnitude or two orders of magnitude higher than that of the outermost layer, and a weighted average glass transition temperature of the order of 600° to 725° C.; and wherein said outermost silica layer has a glass transition temperature of the order of 1200° C.
Claim 5
Dependent Claim
101 words
A multilayer optical structure having increased tensile strength, greater durability, and longer life, comprising: an inner cylindrical core of a first glass composition; and a multilayer cylindrical structure surrounding said core structure consisting of cylindrical layers fused together including an inner cladding layer of a second glass composition fused to said core and an outermost layer of a third glass composition; said outermost layer having a substantially lower coefficient of thermal expanison and a substantially higher glass transition temperature than the coefficient of thermal expansion and glass transition temperature, respectively, of the next-to-outer layer that is fused to said outermost layer.
Claim 6
Dependent Claim
101 words
A multilayer optical structure having increased tensile strength, greater durability, and longer life, comprising: an inner cylindrical core of a first glass composition; and a multilayer cylindrical structure surrounding said core structure consisting of cylindrical layers fused together including an inner cladding layer of a second glass composition fused to said core and an outermost layer of a third glass composition; said outermost layer having a substantially lower coefficient of thermal expanison and a substantially higher glass transition temperature than the coefficient of thermal expansion and glass transition temperature, respectively, of the next-to-outer layer that is fused to said outermost layer.
Claim 7
Dependent Claim
42 words
The multilayer optical structure of claim 4 wherein: said outermost layer has substantially less radial thickness than the thicknesses of the other layers which it surrounds; whereby said optical structure is subject to a high surface compressive stress in said outermost layer.
Claim 8
Dependent Claim
34 words
The multilayer optical structure of claim 5 wherein: said core and any layer surrounded by said outermost layer have a combined radial thickness at least 10 times the radial thickness of said outermost layer.
Claim 9
Dependent Claim
49 words
The multilayer optical structure of claim 5 wherein: said first glass composition is a silicate glass primarily doped with GeO 2 or P 2 O 5 ; said second glass composition is a silicate glass primarily doped with boron; and said third glass composition is a fused silica glass.
Claim 10
Dependent Claim
69 words
The multilayer optical structure of claim 7 wherein: said core, cladding layer, and any intermediate layer have a weighted average coefficient of thermal expansion from one or two orders of magnitude higher than that of the outermost layer, and a weighted average glass transition temperature of the order of 600° to 725° C.; and wherein said outermost layer has a glass transition temperature of the order of 1200° C.
Claim 11
Dependent Claim
136 words
An optical preform comprising: an elongated core of a first doped silica glass; a cladding layer of a second doped silica glass surrounding said core; said core and cladding glasses being selected for good optical transmission characteristics and also for relatively high coefficients of thermal expansion and relatively low glass transition temperatures; and one or more additional layers of glass surrounding said cladding layer, the outermost layer being relatively thin as compared to the thicknesses of interior layers and being composed of a silica glass having a substantially lower coefficient of thermal expansion and a substantially higher glass transition temperature than those of the core and interior layers; whereby the outer surface of said preform is under high compressive stress and may be drawn into a long optical fiber of substantially increased tensile strength and durability.
Claim 12
Dependent Claim
136 words
An optical preform comprising: an elongated core of a first doped silica glass; a cladding layer of a second doped silica glass surrounding said core; said core and cladding glasses being selected for good optical transmission characteristics and also for relatively high coefficients of thermal expansion and relatively low glass transition temperatures; and one or more additional layers of glass surrounding said cladding layer, the outermost layer being relatively thin as compared to the thicknesses of interior layers and being composed of a silica glass having a substantially lower coefficient of thermal expansion and a substantially higher glass transition temperature than those of the core and interior layers; whereby the outer surface of said preform is under high compressive stress and may be drawn into a long optical fiber of substantially increased tensile strength and durability.
Claim 13
Dependent Claim
63 words
The optical preform of claim 9 wherein said core is surrounded by two layers and wherein: the core consists of a silica glass primarily doped with GeO 2 or P 2 O 5 , the first cladding layer consists of a silica glass primarily doped with boron or a germanium-boron mixture, and the second high-compression layer consists of an undoped fused silica glass.
Claim 14
Dependent Claim
22 words
The optical preform of claim 9 wherein: the outermost layer is a titanium silicate glass having a negative coefficient of thermal expansion.
Claim 15
Dependent Claim
147 words
In an optical communication fiber structure having high tensile strength, durability, and fiber life, of the type having a first layer of glass core material having a first optical index of refraction and a second layer of cladding glass material surrounding said core layer and having a second optical index of refraction lower than that of said core layer, said layers forming an inner portion of said fiber structure having efficient light-transmission characteristics and a first average coefficient of thermal expansion and a first average glass transition temperature, the improvement comprising: a third relatively-thin layer of glass material surrounding said second layer and having a second coefficient of thermal expansion substantially lower than that of said inner portion and also having a second glass transition temperature substantially higher than that of said inner portion; whereby said third layer exerts a high compressive force on said second layer.
Claim 16
Dependent Claim
147 words
In an optical communication fiber structure having high tensile strength, durability, and fiber life, of the type having a first layer of glass core material having a first optical index of refraction and a second layer of cladding glass material surrounding said core layer and having a second optical index of refraction lower than that of said core layer, said layers forming an inner portion of said fiber structure having efficient light-transmission characteristics and a first average coefficient of thermal expansion and a first average glass transition temperature, the improvement comprising: a third relatively-thin layer of glass material surrounding said second layer and having a second coefficient of thermal expansion substantially lower than that of said inner portion and also having a second glass transition temperature substantially higher than that of said inner portion; whereby said third layer exerts a high compressive force on said second layer.
Claim 17
Dependent Claim
25 words
The optical communication fiber structure of claim 12 wherein: said inner portion has a radial thickness at least 10 times that of said third layer.
Claim 18
Dependent Claim
22 words
The optical communication fiber structure of claim 13 wherein: said third layer has a radial thickness of between 1 and 10 microns.
Claim 19
Dependent Claim
209 words
An optical preform comprising: an elongated core of a silica glass primarily doped with a material selected from the group of GeO 2 and P 2 O 5 ; a cladding layer of a silica glass primarily doped with a material selected from the group of boron and a germanium-boron mixture surrounding said core; an intermediate layer consisting of a silica glass primarily doped with a material selected from the group of germanium and a germanium-boron mixture, proportioned to have a relatively high coefficient of thermal expansion and a relatively low glass transition temperature, and an outermost high-compression layer consisting of an undoped fused silica glass; said core and cladding layers being selected for good optical transmission characteristics and having relatively high coefficient of thermal expansion and a relatively low glass transition temperature; and the outermost high-compression layer being relatively thin as compared to the thicknesses of the interior layers and being composed of a silica glass having a substantially lower coefficient of thermal expansion and a substantially higher glass transition temperature than those of the core and interior layers; and whereby the outer surface of said preform is under high compressive stress and may be drawn into a long optical fiber of substantially increased tensile strength and durability.
Claim 20
Dependent Claim
209 words
An optical preform comprising: an elongated core of a silica glass primarily doped with a material selected from the group of GeO 2 and P 2 O 5 ; a cladding layer of a silica glass primarily doped with a material selected from the group of boron and a germanium-boron mixture surrounding said core; an intermediate layer consisting of a silica glass primarily doped with a material selected from the group of germanium and a germanium-boron mixture, proportioned to have a relatively high coefficient of thermal expansion and a relatively low glass transition temperature, and an outermost high-compression layer consisting of an undoped fused silica glass; said core and cladding layers being selected for good optical transmission characteristics and having relatively high coefficient of thermal expansion and a relatively low glass transition temperature; and the outermost high-compression layer being relatively thin as compared to the thicknesses of the interior layers and being composed of a silica glass having a substantially lower coefficient of thermal expansion and a substantially higher glass transition temperature than those of the core and interior layers; and whereby the outer surface of said preform is under high compressive stress and may be drawn into a long optical fiber of substantially increased tensile strength and durability.
Claim 21
Dependent Claim
176 words
In an optical communication fiber structure having high tensile strength, durability, and fiber life, of the type having a first layer of glass core material having a first optical index of refraction and a second layer of cladding glass material surrounding said core layer and having a second optical index of refraction lower than that of said core layer, said layers providing efficient light-transmission characteristics, the improvement comprising: a third expansion layer of glass material surrounding said second layer, said three layers forming an inner portion having a first average coefficient of thermal expansion and a first average glass transition temperature; and a fourth compression layer of glass material surrounding said third layer and having a second coefficient of thermal expansion substantially lower than that of said inner portion and a second glass transition temperature substantially higher than that of said inner portion; said fourth layer having substantially less radial thickness than the individual thicknesses of said first, second, and third enclosed layers; whereby said fourth layer exerts a high compressive force on said third layer.
Claim 22
Dependent Claim
176 words
In an optical communication fiber structure having high tensile strength, durability, and fiber life, of the type having a first layer of glass core material having a first optical index of refraction and a second layer of cladding glass material surrounding said core layer and having a second optical index of refraction lower than that of said core layer, said layers providing efficient light-transmission characteristics, the improvement comprising: a third expansion layer of glass material surrounding said second layer, said three layers forming an inner portion having a first average coefficient of thermal expansion and a first average glass transition temperature; and a fourth compression layer of glass material surrounding said third layer and having a second coefficient of thermal expansion substantially lower than that of said inner portion and a second glass transition temperature substantially higher than that of said inner portion; said fourth layer having substantially less radial thickness than the individual thicknesses of said first, second, and third enclosed layers; whereby said fourth layer exerts a high compressive force on said third layer.
Claim 23
Dependent Claim
38 words
The optical communication fiber structure of claim 16 wherein: said inner portion has a radial thickness exceeding 10 times that of said fourth layer, and said fourth layer has a radial thickness of between 1 and 10 microns.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |