| 摘要 |
PROBLEM TO BE SOLVED: To vary drastically a pass wavelength and a passband. SOLUTION: An optical system is constituted of an inputting optical fiber 11, a first convex lens 12, an optical filter 13, a second convex lens 14 and an outputting optical fiber 15, and the optical filter 13 is constituted of a first quadrature reflector 21 reflecting/dividing a parallel beam in the two different directions vertical to the propagative direction of the parallel beam formed by the first convex lens 12, second, third quadrature reflectors 22, 23 reflecting respective beams divided to two parts by the first quadrature reflector 21 in the opposite direction parallel to the reflected direction and a fourth quadrature reflector 24 again multiplexing the beams reflected by the second, third quadrature reflectors 22, 23 and making them the original parallel beams. |
