An optical device has first and second non-parallel optical paths, and a light reflecting surface movable along the defined path. The reflecting surface may have a first and second planar portion connected to the first planar portion. The first planar portion receives light from the first path to reflect the light toward the second path. The second planar portion may form an angle theta 1 with thefirst planar portion. Angle theta 1 satisfies a condition of 175 DEG <=theta 1<180 DEG in either clockwise or counterclockwise rotation from the first planar portion. Returning light to a first optical path can be reduced in an optical component varying the power of a light traveling from the first optical path to a second optical path.