FIBER OPTIC MEASURING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a fiber optic measuring system which accompanies no change in detection sensitivity before and after changes in the ambient temperature and the magnitude of stress of a polarization maintaining fiber.

SOLUTION: The fiber optic measuring system is provided with a Faraday rotator 53 which light passed through the polarization maintaining fiber 4 enters. By setting the rotation angle of the Faraday rotator 53 to be 45 degrees or nearly 45 degrees, a phase difference imparted to light passing through the polarization maintaining fiber 4 in the normal direction can be canceled out by a phase difference imparted to light passing through the polarization maintaining fiber 4 in the reverse direction before and after the changes in the ambient temperature and the magnitude of stress. Elliptically polarized light passing through the polarization maintaining fiber 4 in the reverse direction, thereby becoming the same before and after the changes, so that the detection sensitivity to electric field intensity remains unchanged.

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