Microfiber knot resonator based electric field sensor

An optical fiber electric field sensor was constructed by coating a microfiber based knot resonator with propylene carbonate, a liquid electrooptic material. The Kerr electrooptic effect of propylene carbonate changed the refractive index of the liquid in the presence of an electric field and shifted the fringe pattern of the resonator. The electric field was demodulated by monitoring the fringe shift. The sensor was used to characterize sinusoidal electric fields with magnitudes from 200-4000V/cm and a pulsed field with a 200 mu s duration time. This work may provide practical applications for the characterization of electric fields.