SAGNAC INTERFERENCE TYPE CURRENT SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a sagnac interference type current sensor having inexpensive construction as a whole by constituting optical elements and an optical fiber for connecting mutual optical elements by using an inexpensive single mode optical fiber. SOLUTION: In the sagnac interference type current sensor, a second depolarizer is connected to a second polarizing filter between a phase modulator and a first 1/4-wavelength plate with the second depolarizer on the side of the phase modulator. A third depolarizer is connected to a third polarizing filter between the second polarizing filter and a second 1/4-wavelength plate with the third depolarizer on the side of the second polarizing filter.