| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a variable branching ratio optical splitter which freely branches the inputted light into two light rays in the arbitrary ratio and outputs the same. SOLUTION: In this variable branching ratio optical splitter, a splitting double refractive element 10 which splits the light of the same optical path whose polarization direction is in the vertical relation, an optical path controlling double refractive element 12 which controls the optical path in accordance with the polarization direction and a synthesizing double refractive element 14 which synthesizes the light rays of the different optical paths whose polarization direction is in the vertical relation are arranged in this order leaving a space. A polarization rotating means 16 which transforms the polarization direction from vertical to parallel and a variable polarization rotator 18 which rotates the polarization direction of the light by an arbitrary angle are arranged between the splitting double refractive element and the optical path controlling double refractive element and a polarization controlling means 24 which allows the light rays of two optical paths which are in the diagonal relation to rotate the polarization direction by 90 deg. and allows the light rays of the other two optical path to maintain the polarization direction is arranged between the optical path controlling double refractive element and the synthesizing double refractive element. As a result, the light branching ratio is made freely variable by controlling the rotational angle of the polarization direction by virtue of the variable polarization rotator.</p> |
