| 摘要 |
<p>In a semiconductor Mach-Zehnder modulator, when a phase modulator portion 113 and other passive areas (incident light waveguide path 111, a branch portion 112, a joint portion 114 and an output light waveguide path 115) are formed, a buffer layer 102, a waveguide layer 103 and a clad layer 104 are successively and selectively formed on a semiconductor substrate 101. At this time, a pair of masks having a gap therebetween are used as a selective growth mask. The phase modulator portion 113 is formed in the gap portion of the masks, and the passive areas are formed in the other portions. The band gap and the layer thickness can be partially or locally varied by adjusting the width of the masks and the gap portion, <IMAGE></p> |
