OPTICAL FIBER TYPE CURRENT SENSOR

摘要

PROBLEM TO BE SOLVED: To reduce measurement errors due to a torsion with a simple constitution. SOLUTION: The current sensor has an optical fiber 10, a first and a second light sources 12, 14, a coupler 16, a polarizer 18, a half-wave plate 20, an analyzer 22, wavelength filters 24, 26 and a signal-processing circuit 28. The optical fiber 10 is a single mode optical fiber to every passing light and set around the outer periphery of a conductive conductor 30. The light sources 12, 14 emit lights of different wavelengthsλ1 ,λ2 . The analyzer 22 is disposed behind the half-wave plate 20 to separate the emitted light to two polarized components P, S orthogonal to each other. The wavelength filters 24, 26 arranged behind the analyzer 22 detect the separated polarized components P, S and pass a light of a predetermined wavelength. The signal-processing circuit 28 subtracts the signal separated at the wavelength filters.