| 摘要 |
PROBLEM TO BE SOLVED: To provide a period modulated diffraction grating for reducing the Bragg's wavelength toward the direction of a wave guide passage at the time of current supply by providing a resistance heating film in which the resistance is changed toward the direction of the wave guide passage, to the upper part of the wave guide passage, so that the manufacturing process of elements can be greatly facilitated, and the magnitude of chapping of the grating and the magnitude in the change of chapping can be made variable. SOLUTION: A light wave guide passage 2 fitted with a diffraction grating is provided on a semiconductor clad layer such as an InP, and it is constituted by a semiconductor material (InGaAsP) having a refractive index larger than that of the clad part. Further, a semiconductor clad layer such as the InP, or an insulation layer is formed, and a resistance hating film 5 is formed thereon. The period modulated diffraction grating 10, viewing from the above, is provided with electrode pads 6 consisting of gold or the like and the light wave guide passage 2 is formed to have a given width from the end surface P toward the end surface Q as shown by the dotted lines. Further, the resistance heating film 5 is gradually widened from the end surface P toward the end surface Q, so that the width thereof is varied in the direction of the wave guide passage. |
