Two new fiber optic magnetostrictive phase modulators and magnetometers using the
highly magnetostrictive rare-earth iron compound TbxDyl-xFe2 are investigated. They
demonstrated to have a high sensitivity, dynamic range, minimum field detectability, and a
better structural suitability than metallic glasses. For the first sensor, the experimental
linear phase shifting coefficient was 1.102 rad/Vp-m with the corresponding phase shift
nonnalized to the magnetic field of 0.306 radiO-m. For the second sensor, the
experimental linear phase shifting coefficient was 0.5 rad/Vp-m with the corresponding
phase shift nonnalized to the magnetic field of 0.136 rad/G-m. A minimum detectable
phase shift of better than 1 μrad was obtained, which corresponds to 2 μG/m for a 4 Hz
bandwidth and 1 μG/√HZ per meter of fiber interaction length. The projected minimum
detectable magnetic field for 30 meters, for the first sensor, is thus seen to be 3pT/√HZ.
The experimental results presented have clearly demonstrated the utility of the Terfenol
based magnetostrictive fiber optic phase modulator and magnetometer.
next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
![[VT]](http://scholar.lib.vt.edu/images/ETD-db/restricted.gif)
