Fiber optic high voltage probe

The authors developed a fiber coupled sensor to measure high voltages (/spl sim/45 kV) directly using only light as the probe. They use the Pockels effect in lithium niobate crystals which induces a phase shift in a laser beam that varies according to applied voltage. This can then be transformed into a modulation of beam intensity by polarizers, interferometery or waveguide coupling. No voltage dividers are necessary, nor is any physical connection. This is accomplished by taking advantage of the structure of the power system itself, using voltage planes and dielectric insulation already present as the capacitive voltage divider. They hypothesize a bandwidth from GHz to DC. Such a system could be used in any application that calls for isolated and unobtrusive voltage sensing.