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US 7,060,964 B1Granted
Reflection-mode fiber sensing devices
AssigneeIFOS, Inc.
InventorsBo Pi, Wei-Cheng Wilson Lin, Zhihao Chen
Life of this patent
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Abstract
Fiber sensors formed on side-polished fiber coupling ports based on evanescent coupling are described. Such sensors may be configured to measure various materials and may be used to form multi-phase sensing devices. A Bragg grating may be implemented in such sensors to form reflective fiber sensors.
Claims13
A device, comprising:
- a fiber having a portion of fiber cladding and a portion of underlying fiber core removed to form a flat surface;
- a waveguide formed over said flat surface to have an index greater than said fiber core;
- grating grooves formed atop said waveguide to form a reflective Bragg grating which is within a reach of an evanescent field of guided light in said fiber to reflect guided light that satisfies a Bragg resonance condition;
- an overlay layer formed on said grating grooves whose index changes in response to an external effect;
- and
- a sensing unit to measure a parameter in reflected light from said grating to measure said external effect.
3 more elements
A device, comprising:
- an optical fiber having a portion of optical fiber cladding and a portion of underlying optical fiber core removed to form a flat surface;
- grating grooves formed on exposed portion of said optical fiber core to form a reflective Bragg grating which is within a reach of an evanescent field of guided light in said optical fiber to reflect guided light that satisfies a Bragg resonance condition;
- an overlay layer formed on said grating grooves whose index changes in response to an external effect, said overlay layer having a tapered end section along said optical fiber to reduce an optical loss;
- and
- a sensing unit to measure a parameter in reflected light from said grating to measure said external effect.
2 more elements
A method, comprising:
- providing a fiber sensor in a fiber which comprises a side surface formed on fiber cladding, a waveguide formed over the side surface, and a reflective Bragg grating to reflect light guided by the fiber;
- exposing the fiber sensor to an external medium to cause a change at the Bragg grating;
- monitoring a wavelength shift in a spectral peak in the reflected light;
- and
- extracting information about the external medium based on the wavelength shift.
2 more elements
Dependencies are inferred from the claim text.