PURPOSE: To obtain a practicable optical isolator, by arraying two kinds of Faraday elements which are opposite in rotatory polarization direction, are equal in the absolute value and temp. coefft. of optical rotatory power, have the Verdet's constant equal in both code and absolute value and have an equal length in the optical axis direction in the positions where the optical axes align to each other.
CONSTITUTION: A Faraday element 5 is manufactured by pasting bismuth silicon oxide (BSO) or bismuth germanium oxide (BGO) 6 having left-hand optical rotatory power and BSO or BGO having right-hand optical rotary power of the same length in the positions where the optical axes are aligned to each other. A magnetic field H is applied in the optical axis direction of the element 5. The light from a light source 1 passes a polarizer 2 and is made into linearly polarized light which passes the element 5 and is negated of the rotation by the optical rotary power. Only the rotating angle by the Faraday effect is detected. Since the change of the optical rotary power with temp. is negated, the practicable optical isolator having excellent temp. stability is obtd.
KUHARA MIKI
TATSUMI MASAMI
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