Micro-optical sensor system for pressure, acceleration, and pressure gradient measurements
First Claim
1. A micro-optical sensor system for pressure, acceleration, and pressure-gradient measurements, comprising:
- at least one sensor including;
at least one substrate having a first and a second surface and a substrate material between said first and second surfaces, at least one fiber guide formed in said substrate material extending therethrough between said first and second surfaces, a diaphragm layer formed on said first surface of said at least one substrate, and at least one optical fiber received in said at least one fiber guide, said at least one optical fiber having a fiber tip displaced from said diaphragm layer by a predetermined distance, thereby forming a sensing interferometer having a Fabry-Perot cavity defined between said fiber tip and said diaphragm layer, said fiber tip and said diaphragm layer being optically reflective to form a pair of reflective surfaces of said sensing interferometer; and
a data acquisition and processing unit coupled to said at least one optical fiber for calculating an acoustic/vibration parameter to be measured.
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Accused Products
Abstract
A micro-optical fiber tip based sensor system for pressure, acceleration, and pressure gradient measurements in a wide bandwidth, the design of which allows for multiplexity of the input side of the system is based on micro-electromechanical fabrication techniques. The optical portion of the system is based on low coherence fiber-optic interferometry techniques which has a sensor Fabry-Perot interferometer and a read-out interferometer combination that allows a high dynamic range and low sensitivity to the wavelength fluctuation of the light source. A phase modulation and demodulation scheme takes advantage of the Integrated Optical Circuit phase modulator and multi-step phase-stepping algorithm for providing high frequency and real time phase signal demodulation. The system includes fiber tip based Fabry-Perot sensors each of which has a diaphragm that is used as a transducer.
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Citations
20 Claims
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1. A micro-optical sensor system for pressure, acceleration, and pressure-gradient measurements, comprising:
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at least one sensor including;
at least one substrate having a first and a second surface and a substrate material between said first and second surfaces, at least one fiber guide formed in said substrate material extending therethrough between said first and second surfaces, a diaphragm layer formed on said first surface of said at least one substrate, and at least one optical fiber received in said at least one fiber guide, said at least one optical fiber having a fiber tip displaced from said diaphragm layer by a predetermined distance, thereby forming a sensing interferometer having a Fabry-Perot cavity defined between said fiber tip and said diaphragm layer, said fiber tip and said diaphragm layer being optically reflective to form a pair of reflective surfaces of said sensing interferometer; and
a data acquisition and processing unit coupled to said at least one optical fiber for calculating an acoustic/vibration parameter to be measured. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of fabricating a micro-optical sensor system for acoustic and vibration measurements, comprising the steps of:
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forming a first thin diaphragm layer on a first surface of a first substrate, patterning said first substrate to form at least a first fiber guide therein;
inserting a first optical fiber in said at least a first fiber guide, and displacing a fiber tip of said first optical fiber a first predetermined distance from said first diaphragm layer, thereby forming a first sensing interferometer having a Fabry-Perot cavity defined between said fiber tip and said first diaphragm layer, said fiber tip and said first diaphragm layer being formed optically reflective to form a pair of reflective surfaces of said first sensing interferometer. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A method of fabricating a micro-optical sensor system of multiple pressure measurements, comprising the steps of:
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patterning a plurality of substrates to form fiber guides therein, forming a diaphragm layer on each of said plurality of the substrates, stacking said substrates together to form a single multiple-sensor unit, wherein predetermined fiber guides are aligned each to the other, inserting optical fibers in said fiber guides, positioning a fiber tip of each of said optical fiber a predetermined distance from a respective diaphragm layer, thus forming a plurality of sensing interferometers having a Fabry-Perot cavity defined between each said fiber tip and said respective diaphragm layer, and coupling a data acquisition and processing unit to said optical fibers for calculating acoustic parameters to be measured, said acoustic parameters comprising parameters from a group of acoustic parameters consisting of acoustic pressure, pressure gradient, deflection of a respective diaphragm layer, excitation acceleration, air particle velocity, and acoustic intensity.
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Specification