| 摘要 |
PROBLEM TO BE SOLVED: To provide a composing/branching filter in configuration, which can deal with the wavelength fluctuation of light to be transmitted and further gets suitable for mass production, concerning the composing/branching filter utilizing Bragg reflection. SOLUTION: This composing/branching filter has a three-dimensional optical waveguide 21 for enclosing light in breadthwise direction and thicknesswise direction and propagating light orthogonally to these directions and gratings 4 and 24 provided on the optical waveguide 21 along the propagating direction of light in order to reflect light 6 of specified wavelength in light 5 propagated through the optical waveguide 21. At such a time, since the optical waveguide 21 at the section provided with the gratings 4 and 24 is equipped with a section to continuously change either the width or the thickness of the optical waveguide 21 along the propagating direction of light at least so that the wavelength of reflectable light can be made into wide band. |
