US4227907A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser photochemical synthesis coating of optical fiber
Assignee: United States Department of the Army
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Filing: 1979-10-22
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Granted: 1980-10-14
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Expires: 1999-10-22
Abstract
Abstract Disclosed is a method to prepare and coat an optical fiber with Si 3 ub.4. The Si 3 N 4 is synthesized from SiF 4 +NH 3 and/or SiH 4 +NF 3 by laser photochemical reaction (LPR) techniques in a controlled atmosphere chamber. The silicon fiber which is a representative optical fiber is drawn from a preform at about 2000° C. in a standard fiber drawing furnace. Immediately after drawing of fiber, the fiber is passed through a chamber with a controlled atmosphere containing SiX 4 and NX 3 gases, wherein X equals hydrogen or fluorine. A laser is used to irradiate the atmosphere and the Si 3 N 4 is coated on the optical fiber to a thickness of about 0.02-0.20 micrometer which hermetically seals the fiber and enhances and maintains the mechanical strength thereof.
Inventors
- 👤 James A. Merritt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:26
CPC Classifications
C; C03; C03C; C03C25/00; C03C25/10; C03C25/42; C03C25/12; C03C25/22; Y; Y10; Y10S; Y10S65/00; Y10S65/15; Y10S65/16
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
176 words
In a method of producing an optical fiber of high mechanical strength from a high purity fused silica preform rod wherein the preform rod is heated to its yield point at about 2000° C., a fiber is drawn from the heated preform, and the drawn fiber is immediately hermetically sealed with a layer of silicon nitride of about 0.02 to about 0.20 micrometer thickness, the improvement in said method of hermetically sealing the drawn fiber at room temperature by a laser photochemical reaction process which comprises: (a) placing a drawn silicon fiber in a reaction chamber provided with a salt window transparent to laser radiation; (b) introducing and maintaining a controlled atmosphere of SiX 4 and NX 3 gases, wherein X is selected from hydrogen and fluorine, in said reaction chamber and; (c) irradiating said controlled atmosphere with a predetermined wavelength of a laser to produce Si 3 N 4 which coats and hermetically seals said drawn silicon fiber with a layer of said Si 3 N 4 of about 0.02 to about 0.20 micrometer thickness.
Claim 2
Dependent Claim
176 words
In a method of producing an optical fiber of high mechanical strength from a high purity fused silica preform rod wherein the preform rod is heated to its yield point at about 2000° C., a fiber is drawn from the heated preform, and the drawn fiber is immediately hermetically sealed with a layer of silicon nitride of about 0.02 to about 0.20 micrometer thickness, the improvement in said method of hermetically sealing the drawn fiber at room temperature by a laser photochemical reaction process which comprises: (a) placing a drawn silicon fiber in a reaction chamber provided with a salt window transparent to laser radiation; (b) introducing and maintaining a controlled atmosphere of SiX 4 and NX 3 gases, wherein X is selected from hydrogen and fluorine, in said reaction chamber and; (c) irradiating said controlled atmosphere with a predetermined wavelength of a laser to produce Si 3 N 4 which coats and hermetically seals said drawn silicon fiber with a layer of said Si 3 N 4 of about 0.02 to about 0.20 micrometer thickness.
Claim 3
Dependent Claim
104 words
The method of hermetically sealing a drawn silicon fiber as disclosed by claim 1 wherein said laser photochemical reaction process employs the predetermined wavelength corresponding to the P(36) line of a CO 2 laser, said P(36) line being in resonance with a fundamental band centered at about 1031.8 cm -1 of said SiX 4 , wherein X equals fluorine, and wherein said SiX 4 and NX 3 gases undergo photochemical reactions initiated by said laser line to produce said Si 3 N 4 which coats and hermetically seals at room temperature said drawn silicon fiber with said layer of Si 3 N 4 .
References Cited (Backward Citations)
US4118211A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |