Temperature compensated optical fiber interferometric magnetometer

Claim 1

An interferometric device for measuring the strength of a magnetic field independent of variations in ambient temperature, comprising: a source of coherent light signals; means, optically coupled to said source, for splitting the light signals therefrom into two subsignals of equal amplitude, frequency, and phase; a magnetostrictive rod adapted to be sensitive to variations only in the magnetic field component along its length; a first optical fiber coiled and bonded contiguously and transversely about said rod, and optically coupled at one end to receive one subsignal from said splitting means; two convex caps, each attached to the ends of said rod; a second optical fiber coiled and bonded contiguously about said caps in a direction along the longitudinal axis of said rod, and optically coupled at one end to receive the second subsignal from said splitting means; means, optically coupled to the other end of said first and second fiber, for recombining the subsignals therefrom into a signal the intensity of which varies in proportion to the magnetic field of interest; photodetector means, optically coupled to said recombining means, for receiving the recombined signal and converting it into a substantially equivalent electrical signal; and processing means, connected to said photodetector means, for determining the strength of the magnetic field.