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US5249251A
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Optical fiber sensor having an active core
Assignee: National Aeronautics and Space Administration
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Filing: 1992-03-18
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Granted: 1993-09-28
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Expires: 2012-03-18
Abstract
Abstract An optical fiber is provided comprising an active fiber core which produces waves of light upon excitation. A factor ka is identified and increased until a desired improvement in power efficiency is obtained. The variable "a" is the radius of the active fiber core and "k" is defined as 2πλ, wherein λ is the wavelength of the light produced by the active fiber core. In one embodiment, the factor ka is increased until the power efficiency stabilizes. In addition to a bare fiber core embodiment, a two-stage fluorescent fiber is provided wherein an active cladding surrounds a portion of the active fiber core having an improved ka factor. The power efficiency of the embodiment is further improved by increasing a difference between the respective indices of refraction of the active cladding and the active fiber core.
Inventors
- 👤 Claudio O. Egalon
- 👤 Robert S. Rogowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:51
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/02033; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N21/6428; G01N21/75; G01N21/76; G01N21/77; G01N21/7703; G02B1/00; G02B1/04; G02B1/045; G02B1/046; G01N2021/7706; G01N2021/7709; G01N2021/7713
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
103 words
A process for obtaining a desired power efficiency of an optical fiber comprising the steps of: providing active fiber cores which produce waves of light upon excitation, the fiber cores having various respective core radii and producing light waves having various respective wavelengths; and increasing a factor ka until the desired power efficiency is obtained, wherein a is the radius of a particular active fiber core and k=2π/λ, wherein λ is the wavelength of the light waves produced by the particular active fiber core upon excitation; and selecting the active fiber core characterized by the factor ka which produces the desired power efficiency.
Claim 2
Dependent Claim
103 words
A process for obtaining a desired power efficiency of an optical fiber comprising the steps of: providing active fiber cores which produce waves of light upon excitation, the fiber cores having various respective core radii and producing light waves having various respective wavelengths; and increasing a factor ka until the desired power efficiency is obtained, wherein a is the radius of a particular active fiber core and k=2π/λ, wherein λ is the wavelength of the light waves produced by the particular active fiber core upon excitation; and selecting the active fiber core characterized by the factor ka which produces the desired power efficiency.
Claim 3
Dependent Claim
25 words
The process according to claim 1, wherein the factor ka is increased until the power efficiency of the optical fiber stabilizes after an initial increase.
Claim 4
Dependent Claim
54 words
The process according to claim 1, further comprising surrounding a portion of the particular active fiber core with an active cladding which produces waves of light upon excitation and wherein the particular active fiber core is provided with fluorescent substances which produce light when excited by the light produced by the excited active cladding.
Claim 5
Dependent Claim
26 words
The process according to claim 1, further comprising surrounding another portion of the particular active fiber core with an inactive guide cladding which guides the light.
Claim 6
Dependent Claim
43 words
The process according to claim 3, further comprising increasing a difference between n core -n clad , wherein n core is the index of refraction of the particular active fiber core and n clad is the index of refraction of the active cladding.
Claim 7
Dependent Claim
25 words
The process according to claim 5, wherein the difference between the respective indices of refraction of the core and cladding is greater than approximately 0.01.
Claim 8
Dependent Claim
22 words
The process according to claim 5, wherein the respective indices of refraction are related by the following: 3.0>n core >n clad >1.0.
Claim 9
Dependent Claim
22 words
The process according to claim 1, wherein the factor ka is in the range of approximately 90 to approximately 1.6×10 4 .
Claim 10
Dependent Claim
26 words
The process according to claim 1, wherein the respective radii a of the active cores are in the range of 10 μm to 10 3 μm.
Claim 11
Dependent Claim
20 words
The process according to claim 1, wherein the active fiber cores product light having wavelengths λ in the visible range.
Claim 12
Dependent Claim
24 words
The process according to claim 1, wherein the active fiber cores produce light having wavelengths in the range of 0.4 μm to 0.7 μm.
Claim 13
Dependent Claim
102 words
An optical fiber having a desired power efficiency prepared by a process comprising the steps of: providing active fiber cores which produce waves of light upon excitation, the fiber cores having various respective core radii and producing light waves having various respective wavelengths; increasing a factor ka until the desired power efficiency is obtained, wherein a is the radius of a particular active fiber core and k=2π/λ, wherein λ is the wavelength of the light waves produced by the particular active fiber core upon excitation; and selecting the active fiber core characterized by the factor ka which produces the desired power efficiency.
Claim 14
Dependent Claim
102 words
An optical fiber having a desired power efficiency prepared by a process comprising the steps of: providing active fiber cores which produce waves of light upon excitation, the fiber cores having various respective core radii and producing light waves having various respective wavelengths; increasing a factor ka until the desired power efficiency is obtained, wherein a is the radius of a particular active fiber core and k=2π/λ, wherein λ is the wavelength of the light waves produced by the particular active fiber core upon excitation; and selecting the active fiber core characterized by the factor ka which produces the desired power efficiency.
Claim 15
Dependent Claim
33 words
The optical fiber according to claim 12, wherein said active fiber core contains chemiluminescent substances which react with an analyte to produce light and wherein said active core is permeable by the analyte.
Claim 16
Dependent Claim
25 words
The optical fiber according to claim 12, wherein said active fiber core contains fluoroluminescent substances which produce light upon excitation by an outside light source.
Claim 17
Dependent Claim
26 words
The optical fiber according to claim 12, wherein the factor ka is increased until the power efficiency of the optical fiber stabilizes after an initial increase.
Claim 18
Dependent Claim
58 words
The optical fiber prepared by the process according to claim 12, further comprising surrounding a portion of the particular active fiber core with an active cladding which produces waves of light upon excitation and wherein the particular active fiber core is provided with fluorescent substances which produce light when excited by light produced by the excited active cladding.
Claim 19
Dependent Claim
16 words
The optical fiber according to claim 16, wherein the active cladding is permeable to an analyte.
Claim 20
Dependent Claim
23 words
The optical fiber according to claim 16, wherein the active fiber core contains chemiluminescent substances which react with the analyte to produce light.
Claim 21
Dependent Claim
26 words
The optical fiber according to claim 16, wherein the active fiber core contains fluoroluminescent substances which are excited by an outside light source to produce light.
Claim 22
Dependent Claim
46 words
The optical fiber prepared by the process according to claim 16, further comprising increasing a difference between the index of refraction of the active cladding and the index of refraction of the particular active fiber core to further improve the power efficiency of the optical fiber.
Claim 23
Dependent Claim
45 words
The optical fiber prepared by the process according to claim 20, wherein the difference between the respective indices of refraction is greater than approximately 0.01, wherein the index of refraction of the active core is greater than the index of refraction of the active cladding.
Claim 24
Dependent Claim
53 words
The optical fiber prepared by the process according to claim 20, wherein the respective indices of refraction are related by the following: 3.0>n core >n clad >1.0, wherein n clad is the index of refraction of the active cladding and n core is the index of refraction of the particular active fiber core.
Claim 25
Dependent Claim
22 words
The process according to claim 12, wherein the factor ka is in the range of approximately 90 to approximately 1.6×10 4 .
Claim 26
Dependent Claim
31 words
The optical fiber prepared by the process according to claim 12, wherein the respective radii a of the active cores are in the range of 10 μm to 10 3 μm.
Claim 27
Dependent Claim
25 words
The optical fiber prepared by the process according to claim 12, wherein the active fiber cores produce light having wavelengths λ in the visible range.
Claim 28
Dependent Claim
29 words
The optical fiber prepared by the process according to claim 12, wherein the active fiber cores produce light having wavelengths in the range of 0.4 μm to 0.7 μm.
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