Compact Tb doped fiber optic current sensor with high sensitivity
A highly sensitive fiber optic current sensor using terbium doped fiber is presented. The Verdet constant of the terbium doped fiber at 1300nm is found to be 19.5μrad/A using both a polarimetric and interferometric type sensor. Measurements on a Sagnac-loop sensor using 10cm of terbium doped fiber placed inside a solenoid show over 40dB of open loop dynamic range as well as a minimum detectable current of 0.1mA.