| 摘要 |
<P>PROBLEM TO BE SOLVED: To simultaneously compensate dispersion and a dispersion slope and to reduce insertion loss. <P>SOLUTION: Light emitted from an optical fiber 2 is converged in a uniaxial direction by a cylindrical lens 4, made incident on a Fabry-Perot interferometer 5, and distributed in an X axis direction by changing an emitting angle by a wavelength by the interferometer 5. Further, it is image-formed at a focus position A by a converging lens 6 and reflected at a concave diffraction grating 7, a deflection angle is made different by the wavelength, and it is reflected on the reflection surface 8a of a reflection mirror 8 and made to travel through an optical path in an opposite direction. By the Fabry-Perot interferometer 5 and the concave diffraction grating 7, emission angles on a Y-Z plane and an X-Z plane are made different for each wavelength. A converging position A and the reflection surface 8a are provided on the circumference of a Rowland circle whose diameter is the radius R of the reflection surface of the concave diffraction grating. By forming the reflection surface 8a to different free curved surfaces for the Y-Z plane and the X-Z plane and shifting a reflection position for each wavelength, an optical path length difference is provided for each wavelength and the dispersion and the dispersion slope are compensated. <P>COPYRIGHT: (C)2004,JPO |
