| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical semiconductor element that has a vertical-groove diffraction grating on a side wall capable of suppressing an increase in element resistance while suppressing the generation of a lateral higher mode. <P>SOLUTION: The optical semiconductor element has a semiconductor substrate, a waveguide structure which is a waveguide structure formed by etching a lamination grown above the semiconductor substrate and having a width specified by side walls and has a wide part with a width wide along a waveguide direction, a narrow part with a narrow width, and an intermediate part for connecting the wide part with the narrow part, and a diffraction grating which is formed at least on either of the side walls of the wide part and narrow part of the waveguide structure, has vertical grooves periodically formed along the waveguide direction, and specifies the wavelength of the propagated light of the waveguide structure. The narrow part is formed so as to give a loss of more than 50% to a high-order lateral mode. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
