Optical fiber with microgratings for increased measurable strain range
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.
Claims19
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 the 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.
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 the 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.
Dependencies are inferred from the claim text.