CURRENT/MAGNETIC FIELD MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a current/magnetic field measuring apparatus utilizing the Faraday effect which permits measurement at a higher accuracy by eliminating effect of external magnetic fields along with a higher dynamic range. SOLUTION: A laser diode 1 is driven by an LD driver 2 to supply exciting light to a fiber laser. The light is guided to a coupler 4 with a transmission fiber 3 and further to a ring resonator 5 of a ring laser with the coupler 4. The ring resonator 5 is composed of an optical fiber containing a laser medium having a light amplifying action and wound on the circumference of a primary conductor 6 to be measured. Beat frequency generated in the ring laser by the Faraday effect is determined thereby obtaining a current value of the primary conductor 6.