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US 2020/0025592 A1Published application
Methods and apparatus for interferometric interrogation of an optical sensor
AssigneeLuna Innovations Incorporated
InventorsJanet Renee Pedrazzani, Matthew Davis, Evan M. Lally
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Abstract
A high-speed interrogation system is provided for interferometric sensors, one example of which is an EFPI sensor, that operates based on spectral interference. The system uses a two mode operation that includes a lower speed, accurate absolute measurement mode and a higher speed, relative measurement mode. The system achieves greater overall measurement accuracy and speed than known sensor interrogation approaches.
Claims25
(canceled)
A measuring method for use with an interferometric sensor, comprising:
- operating one or more light sources to provide light over a range of source wavelengths including providing light at three or more wavelengths to the interferometric sensor;
- determining a period of an interferometric amplitude response of an interferometric signal produced by the interferometric sensor over the range of source wavelengths;
- determining an absolute optical path length associated with the interferometric sensor based on the determined period of the interferometric amplitude response of the interferometric signal over the range of source wavelengths, where the optical path length varies depending on one or more physical parameters to be measured using the interferometric sensor;
- providing light at two or more selected wavelengths to the interferometric sensor, with two of the selected wavelengths having two different relative phases on the interferometric amplitude response;
- measuring a first interferometric amplitude response of an interferometric signal produced by the interferometric sensor at a first of the two or more selected wavelengths;
- measuring a second interferometric amplitude response of an interferometric signal produced by the interferometric sensor at a second of the two or more selected wavelengths;
- determining a relative optical path length change based on the first interferometric amplitude response at the first selected wavelength and the second interferometric amplitude response at the second selected wavelength;
- combining the absolute optical path length with the relative optical path length change to determine a current absolute optical path length;
- and
- generating a signal corresponding to the current absolute optical path length that relates to a current sensor measurand value or from which a current sensor measurand value is determined.
7 more elements
A system for use with an interferometric sensor, comprising:
- one or more light sources to provide light over a range of source wavelengths including providing light at three or more wavelengths to the interferometric sensor;
- processing circuitry to:
- determine a period of an interferometric amplitude response of an interferometric signal produced by the interferometric sensor over the range of source wavelengths;
- determine an absolute optical path length associated with the interferometric sensor based on the determined period of the interferometric amplitude response of the interferometric signal over the range of source wavelengths, where the optical path length varies depending on one or more physical parameters to be measured using the interferometric sensor;
- wherein the one or more light sources provide light at two or more selected wavelengths to the interferometric sensor, with two of the selected wavelengths having two different relative phases in the interferometric amplitude response;
- wherein the processing circuitry is configured to:
- measure a first interferometric amplitude response of an interferometric signal produced by the interferometric sensor at a first of the two or more selected wavelengths;
- measure a second interferometric amplitude response of an interferometric signal produced by the interferometric sensor at a second of the two or more selected wavelengths;
- determine a relative optical path length change based on the first interferometric amplitude response at the first selected wavelength and the second interferometric amplitude response at the second selected wavelength;
- combine the absolute optical path length with the relative optical path length change to determine a current absolute optical path length;
- and
- generate a signal corresponding to the current absolute optical path length that relates to a current sensor measurand value or from which a current sensor measurand value is determined.
9 more elements
Dependencies are inferred from the claim text.