| 摘要 |
<p>A phase-shifted diffraction grating for devices such as semiconductor lasers is produced by forming a first diffraction grating pattern of a first material having a reference pitch on a substrate. The substrate is then coated with a second material on both the first material and an exposed portion of the substrate in a region where a second diffraction grating having a pitch which is the reverse of the reference pitch of the first diffraction grating pattern is to be formed. The first material is removed by lift off to obtain the second diffraction grating pattern on the second diffraction grating region. The substrate is etched using the first diffraction grating as an etching mask to form the first diffraction grating and then the substrate is etched with the second diffraction grating pattern as an etching mask to obtain a second diffraction grating continuous with the first diffraction grating. The first diffraction grating pattern may have a rectangular or square shape to stably and accurately remove the first material by lift-off and the boundary between the first and second diffraction gratings can be stably and accurately defined by self-alignment. <IMAGE></p> |
