Ultra-miniature fiber-optic pressure sensor system and method of fabrication
First Claim
1. A surface-mountable ultra-miniature fiber-optic pressure sensor system, comprising:
- at least one sensing head, said at least one sensing head being formed on an optical fiber having an optical guide channel defined within sidewalls and extending between an input end and a tip end of said optical fiber, wherein said tip end of said optical fiber is formed with an end surface angled substantially at 45°
relative to an optical axis of said optical guide channel of said optical fiber and covered with a first reflective layer, wherein said reflective angled end surface redirects light traveling along said optical guide channel from said input end toward said tip end to impinge on said sidewall of said optical fiber at a predetermined location thereof; and
a Fabry-Perot cavity structure formed at said predetermined location at said sidewalls of said optical fiber;
wherein optical characteristics of an optical output signal emanating from the input end of said optical fiber correspond to a pressure applied to said Fabry-Perot cavity structure.
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Accused Products
Abstract
Ultra-miniature surface-mountable Fabry-Perot pressure sensor is constructed on an optical fiber which utilizes a 45° angled fiber tip covered with a reflective layer which steers the optical axis of the fiber by 90°. The Fabry-Perot cavity is formed on the sidewall of the fiber and a polymer-metal composite diaphragm is formed on the top of the Fabry-Perot cavity to operate as a pressure transducer. The sensor exhibits a sufficient linearity over the broad pressure range with a high sensitivity. The sensitivity of the sensor may be tuned by controlling the thickness of the diaphragm. The sensor may be used in a wide range of applications, including reliable in vivo low invasive pressure measurements of biological fluids, single sensor systems, as well as integral spatial-division-multiplexing sensor networks. Methods of batch production of uniform device-to-device Fabry-Perot pressure sensors of co-axial and cross-axial configurations are presented.
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Citations
20 Claims
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1. A surface-mountable ultra-miniature fiber-optic pressure sensor system, comprising:
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at least one sensing head, said at least one sensing head being formed on an optical fiber having an optical guide channel defined within sidewalls and extending between an input end and a tip end of said optical fiber, wherein said tip end of said optical fiber is formed with an end surface angled substantially at 45°
relative to an optical axis of said optical guide channel of said optical fiber and covered with a first reflective layer, wherein said reflective angled end surface redirects light traveling along said optical guide channel from said input end toward said tip end to impinge on said sidewall of said optical fiber at a predetermined location thereof; anda Fabry-Perot cavity structure formed at said predetermined location at said sidewalls of said optical fiber; wherein optical characteristics of an optical output signal emanating from the input end of said optical fiber correspond to a pressure applied to said Fabry-Perot cavity structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for manufacturing a surface-mountable ultra-miniature fiber-optic pressure sensor system, comprising the steps of:
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fabricating at least one sensing head by; (a). contouring a tip end of an optical fiber with an end surface angled at substantially 45°
relative to an optical guide channel defined by sidewalls of said optical fiber,(b). depositing a first reflective layer on said end surface, (c). inputting a light beam at an input end of said optical fiber, wherein said light beam travels from said input end toward said tip end of said optical fiber along said optical guide channel thereof and redirects at said reflective angled end surface toward a predetermined location at said sidewalls of said optical fiber, and (d). forming a Fabry-Perot cavity structure at said predetermined location of said sidewalls of said optical fiber, said Fabry-Perot cavity structure having a cavity and a diaphragm covering a top of said cavity. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of manufacturing a plurality of ultra-miniature fiber-optic pressure sensors, comprising the steps of:
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removing a fiber jacket from an end area of each of a plurality of optical fibers to expose sidewalls thereof, securing said plurality of optical fibers to a holding member in alignment each with the other, polishing the tips of said plurality of optical fibers to form end surfaces angled at a predetermined angle relative to an optical guide channel of each optical fiber, forming a cavity confining layer at a predetermined location of said plurality of optical fibers, said predetermined location including a location selected from a group consisting of;
said sidewalls of said optical fibers, said end surfaces of said optical fibers, and combinations of said sidewalls and said end surfaces, andforming a Fabry-Perot cavity structure at said predetermined location by the steps of; (a) removing a material of said cavity confining layer to form a cavity of predetermined dimensions through the thickness of said cavity confining layer, (b) pre-forming a polymer diaphragm film of a uniform thickness, (c) covering said pre-formed polymer film on tops of said cavities of said plurality of optical fibers, thereby forming a polymer diaphragm layer of each said Fabry-Perot cavity structure, and (d) coating a reflective diaphragm layer on said polymer diaphragm layer. - View Dependent Claims (19, 20)
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Specification