To provide a polarization controller which is less fluctuated in loss and deteriorated in extinction ratio and has good reproducibility of a polarization state.
The light emitted from an optical fiber 1 is converted into parallel beams by a lens 2, is then transmitted through a Faraday element 3 and is condensed at the incident end of an optical fiber 7 by a lens 6. A magnetic field is applied on this Faraday rotator 3 in its optical axis direction and further, a magnetic field is applied thereon in a direction perpendicular to the optical axis by a pair of magnets 5a, 5b. The direction of the combined magnetic fields is rotated when the current of the coil 4 is changed from I to -I. The polarization of the transmitted light may be thereupon controlled by arbitrarily changing the current of the coil 4.
OSHIMA SHIGERU
NAKAMURA MITSUKO
SHIMANUKI SENJI
TAKAHIRA HITOSHI
YAMAMOTO SHU
KOKUSAI DENSHIN DENWA CO LTD