Patent ID: 8098967

Claim:
A system, comprising: a magnetic flux sensor, comprising: an optical fiber; at least one twin-grating structure formed on the optical fiber, each twin-grating structure comprising: a first optical grating, structure, a second optical grating structure adjacent the first optical grating structure, and a sensing cavity disposed between the first and second optical grating structures, each twin-grating structure selectively responsive to a unique wavelength of light to generate an optical interference fringe signal; and a magnetostrictive coating disposed over each twin-grating structure, the magnetostrictive coating to change an optical property of the twin-grating structure and a phase of the optical interference fringe signal when the magnetostrictive coating is exposed to changing magnetic flux; a laser source coupled to the magnetic flux sensor to input light into the optical fiber, the laser source configured to output the unique wavelength of each twin-grating structure; an optical detector coupled to the optical fiber to generate, for each twin grating structure, an electrical interference fringe signal representative of the optical interference fringe signal generated by the twin-grating structure; and a processor coupled to the optical detector, the processor programmed to, for each twin-grating structure of the magnetic flux sensor, extract a target fringe of the optical interference fringe, signal based on a digital representation of the electrical interference fringe signal and track variation in a phase of the target fringe over time to determine variation in the magnetic flux.