Patent ID: 7492463
Filing Date: 2009-02-17
Classification: G01B,G01D,G01L

Abstract:
1. A system for monitoring and quantitatively measuring displacement of reflective surfaces in a Fabry-Perot sensor, the system comprising: a laser providing light tunable over a range of frequencies and tunable at a fast scan rate over a subset of said range of frequencies; said Fabry-Perot sensor spanning a variable gap defined by two reflective surfaces, said Fabry-Perot sensor receiving and modulating light interrogating the Fabry-Perot sensor; detector means for generating a detector signal from a normalized intensity ratio of light modulated when the laser interrogates the Fabry-Perot senor over the range of frequencies or interrogates the Fabry-Perot sensor at a fast scan rate over the subset of the range of frequencies; signal conditioner means for identifying at least two frequency minima in the detector signal when the Fabry-Perot sensor is interrogated over the range of frequencies and monitoring one of the at least two minima in the detector signal when the Fabry-Perot sensor is interrogated at a fast scan rate over the subset of the range of frequencies; and calculating means for calculating an absolute value for the variable gap based on the at least two minima and detecting changes in one of the at least two minima when the Fabry-Perot sensor is interrogated at a fast scan rate over the subset of the range of frequencies.