An optical fiber with microgratings and methods and apparatus for making and using same
AssigneeIntuitive Surgical Operations, Inc.
InventorsMark E. Froggatt, Dawn K. Gifford, Alexander K. Sang
Life of this patent
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Abstract
An optical fiber with one or more microgratings is disclosed. Methods and apparatus are described for making an optical fiber with one or more microgratings. Methods and apparatus are described for an optical fiber with one or more microgratings Optical sensing methods and an optical sensing system effectively decouple strain range from the laser tuning range, permit the use of a smaller tuning range without sacrificing strain range, and compensate for ambiguity in phase measurements normally associated with smaller tuning ranges.
Claims30
An optical sensor for use with a tunable laser that generates light over a range of wavelengths corresponding to a tuning range of the tunable laser, the optical sensor comprising:
- an optical fiber including one or more cores, wherein, for each core of the one or more cores:
- the core is inscribed with a first grating at a first grating location along a length of the core and a second grating located at a second grating location along the length of the core;
- a width of a spectrum of a reflection from at least one of the first grating and the second grating is larger than a tuning range of the tunable laser, wherein the width of the spectrum of the reflection enables measurement of reflections for a predetermined range of strains to be measured by the optical sensor, the predetermined range of strains including a maximum strain that creates a wavelength shift greater than half of the tuning range of the tunable laser, and
- a portion of the spectrum of the reflection is within the tuning range of the tunable laser for the predetermined range of strains.
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A method for making an optical fiber sensor, the method comprising:
- generating an ultraviolet light beam;
- splitting the ultraviolet light beam into a first ultraviolet light beam and a second ultraviolet light beam;
- focusing the first ultraviolet light beam so the first ultraviolet light beam is narrower in width than the second ultraviolet light beam;
- combining the first ultraviolet light beam and the second ultraviolet light beam to form an interference pattern that extends across multiple cores in the optical fiber sensor;
- and
- exposing the optical fiber sensor to the interference pattern to inscribe a first grating in each core of the multiple cores.
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An optical sensing system comprising:
- a tunable laser to generate light over a range of wavelengths corresponding to a tuning range of the tunable laser;
- an optical fiber including one or more cores, wherein, for each core of the one or more cores:
- the core is inscribed with a first grating at a first grating location along a length of the core and a second grating located at a second grating location along the length of the core;
- a width of a spectrum of a reflection from at least one of the first grating and the second grating is larger than a tuning range of the tunable laser, the width of the spectrum of the reflection enables measurement of reflections for a predetermined range of strains to be measured by the optical sensing system, the predetermined range of strains including a maximum strain that creates a wavelength shift greater than half of the tuning range of the tunable laser, and
- a portion of the spectrum of the reflection is within the tuning range of the tunable laser for the predetermined range of strains;
- and
- circuitry, coupled to the optical fiber, configured to:
- detect measured reflection data from the optical fiber over the tuning range of the tunable laser, and
- determine a strain on the optical fiber based on a change in the measured reflection data.
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Dependencies are inferred from the claim text.