Fiber optics gas sensor
First Claim
1. An apparatus for detecting the presence of a gas for use with a source of elliptically polarized light, comprising:
- an optical waveguide having a circumference; and
a transparent variable index means deposited in a layer over at least a portion of the circumference of said optical waveguide for exchanging electrons with a gas to be detected at reactive sites on the surface of said variable index means by the process of adsorption, thereby varying the refractive index of said variable index means and altering the ellipticity of a light transmitted through the optical waveguide as a function of the presence of said gas.
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Accused Products
Abstract
The adsorption of gas on a solid surface can produce considerable variation in the optical properties of the solid surface and eventually lead to the identification of the gas adsorbed. An optical waveguide having at least a portion of its length circumferentially coated with a transparent semiconductor material may function as a gas sensor. The sensor functions by exchanging electrons with a detectable gas brought in proximity with the coating material at reactive sites on the material'"'"'s surface by the process of adsorption, thereby varying the refractive index of the transparent semiconductor material and altering the ellipticity of a light transmission through the optical waveguide. Substantially monochromatic polarized light is transmitted through the optical waveguide and then quantified by a light detector. A meter or other device connected to the light detector is adjusted to register a variation in the signal received by the light detector, indicating the presence of a detectable gas.
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Citations
30 Claims
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1. An apparatus for detecting the presence of a gas for use with a source of elliptically polarized light, comprising:
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an optical waveguide having a circumference; and a transparent variable index means deposited in a layer over at least a portion of the circumference of said optical waveguide for exchanging electrons with a gas to be detected at reactive sites on the surface of said variable index means by the process of adsorption, thereby varying the refractive index of said variable index means and altering the ellipticity of a light transmitted through the optical waveguide as a function of the presence of said gas. - View Dependent Claims (2, 3, 4, 5)
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6. A system for detecting the presence of a gas, comprising:
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an optical light source; an optical waveguide having an input end and an output end, said input end elliptically coupled to said light source, said optical waveguide having a circumference; transparent variable index means deposited along at least a portion of the circumference of said waveguide for exchanging electrons with a gas to be detected at reactive sites on the surface of said variable index means by the process of adsorption, thereby varying the refractive index of said variable index means and altering the ellipticity of a light transmitted through the optical waveguide; and optical-to-electronic detector means optically coupled to the output end of the waveguide for detecting and quantifying the presence of a gas to be detected by detecting a change in the ellipticity of a light transmitted through said optical waveguide. - View Dependent Claims (7)
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8. An apparatus for detecting the presence of a gas, comprising:
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a pair of optical waveguides comprising a first optical waveguide optically coupled to a second optical waveguide at a contact area, each said optical waveguide having a circumference; transparent variable index means deposited in a layer over at least a portion of the circumference of each of said optical waveguides proximal said contact area for exchanging electrons with a gas to be detected at reactive sites on the surface of said variable index means by the process of adsorption, thereby varying the refractive index of said semiconductor material and altering the ratio of a light transmission through said optical waveguides; and optical-to-electronic detector means located at a first end of said pair of optical waveguides for detecting and quantifying the presence of a gas to be detected by detecting a change in said ratio of light transmitted through said optical waveguides. - View Dependent Claims (9, 10, 11, 12)
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13. A method of detecting gas, comprising the steps of:
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providing an optical waveguide upon which transparent semiconductor material has been deposited in a sensor layer over at least a portion of a circumference of said optical waveguide; placing said semiconductor-coated optical waveguide in a chamber; propagating polarized light through said optical waveguide; detecting and quantifying light transmitted from said optical waveguide; allowing a gas to be detected to enter said chamber; reacting said gas with said semiconductor sensor layer whereby said semiconductor material exchanges electrons in said gas at reactive sites on the surface of said semiconductor material by the process of adsorption, thereby varying the refractive index of said semiconductor material and alters the ellipticity of said light propagated through the optical waveguide; and detecting a change in said ellipticity of said light transmitted from said optical waveguide in the presence of said gas. - View Dependent Claims (14, 15, 16, 17)
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18. A method of detecting gas, comprising the steps of:
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providing a pair of optical waveguides comprising a first optical waveguide optically coupled to a second optical waveguide at a contact area, said first and second optical waveguides each having a transparent semiconductor material deposited in a layer over at least a portion of its circumference proximal said contact area; placing said optical waveguide pair in a chamber;
transmitting polarized light through said first optical waveguide;detecting and quantifying light transmitted through said optical waveguide pair; allowing a gas to be detected to enter said chamber; reacting said gas with said transparent semiconductor layer whereby said semiconductor material exchanges electrons with said gas at reactive sites on the surface of said semiconductor material by the process of adsorption, thereby varying the refractive index of said semiconductor material and altering the ratio of said light transmission through said optical waveguides; and detecting a change in said ratio of said light transmitted from said optical waveguides in the presence of said gas. - View Dependent Claims (19, 20, 21)
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22. An apparatus for detecting the presence of a gas for use with a source of light, comprising:
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an optical waveguide having a circumference, a light-input end and a light-emitting end; and a variable index means deposited in a layer over at least a portion of the circumference of said optical waveguide for altering the ellipticity of a light transmission through the optical waveguide as a function of the presence of said gas. - View Dependent Claims (23, 24, 25)
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26. An apparatus for detecting the presence of a gas for use with a source of light, comprising:
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an optical waveguide having a circumference; and a transparent, organic semiconductor material deposited in a layer over at least a portion of the circumference of said optical waveguide. - View Dependent Claims (27)
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28. An apparatus for detecting the presence of a gas, comprising:
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a pair of optical waveguides comprising a first optical waveguide optically coupled to a second optical waveguide at a contact area, each said optical waveguide having a circumference; variable index means deposited in a layer over at least a portion of the circumference of each of said optical waveguides proximal said contact area for altering the relative proportion of a light transmission through each of said optical waveguides in response to adsorption of a gas by said variable index means; and optical-to-electronic detector means located at a first end of each of said pair of optical waveguides for detecting and quantifying the presence of a gas to be detected by detecting a change in a ratio of light transmitted through each of said optical waveguides, respectively. - View Dependent Claims (29, 30)
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Specification