VARIABLE OPTICAL ATTENUATOR AND ITS INTENSITY ADJUSTMENT METHOD

PROBLEM TO BE SOLVED: To simplify the variable optical attenuator compared with the conventional ones which uses a Faraday element by dispensing with the polarizer and optical analyzer, while using a Faraday element. SOLUTION: This variable optical attenuator is composed of an optical fiber 11 to emit a light beam to an optical element; a collimator lens 12 to obtain parallel light of the radiated light from the optical fiber 11; a Faraday element 13 which changes the light amount by rotating the polarization plane of the linear polarization in proportion to the strength of the applied magnetic field; a collimator lens 14 to condense the 0th order diffracted light which is not diffracted by the Faraday element 13; an optical fiber 15 to input the light condensed by the collimator lens 14; and a coil 16 to apply a magnetic field to the Faraday element 13 in the direction of the light. This Faraday element 13 is constituted, in such a way that the magnetization direction is different one another in the neighboring magnetic domains, so that the magnetization direction becomes parallel with the direction of light. COPYRIGHT: (C)2005,JPO&NCIPI