Optical fiber with microgratings for increased measurable strain range
AssigneeIntuitive Surgical Operations, Inc.
InventorsMark E. Froggatt, Dawn K. Gifford, Alexander K. Sang
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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.
Claims20
A method for making an optical sensor, the optical sensor comprising multiple optical cores extending along a length of the optical 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 to produce a narrower first ultraviolet light beam, wherein the narrower first ultraviolet light beam is narrower in width than the second ultraviolet light beam;
- crossing the narrower first ultraviolet light beam and the second ultraviolet light beam to form an interference pattern that extends across the multiple optical cores;
- and
- exposing the optical sensor to the interference pattern at a first location along the length of the optical sensor to inscribe first gratings in the multiple optical cores at the first location.
An optical sensor comprising:
- multiple optical cores extending along a length of the optical sensor;
- and
- first microgratings in the multiple optical cores at a first location along the length of the optical sensor, the first microgratings created by exposing the optical sensor at the first location to an interference pattern extending across the multiple cores;
- wherein the interference pattern results from crossing a focused first ultraviolet light beam with a second ultraviolet light beam that is wider than the first ultraviolet light beam.
An apparatus for writing gratings onto multiple optical cores of an optical sensor, the apparatus comprising:
- a horizontal cylindrical lens configured to focus a collimated ultraviolet light beam into a line to generate a focused ultraviolet beam;
- a phase mask configured to split the focused ultraviolet beam into a first ultraviolet light beam and a second ultraviolet light beam;
- a vertical cylindrical lens configured to focus the first ultraviolet light beam into a narrower first ultraviolet beam, the narrower first ultraviolet light beam being narrower in width than the second ultraviolet light beam;
- and
- first and second tiltable mirrors configured to together direct the narrower first ultraviolet beam and the second ultraviolet beam to cross and form an interference pattern across the multiple optical cores.
Dependencies are inferred from the claim text.