| 摘要 |
<p>An electro-optical modulator includes a rib waveguide formed of a laminate of a first semiconductor layer (8) and a second semiconductor layer (9) stacked thereon via a dielectric film (11), the conductivity types of the semiconductor layers differing from each other. The semiconductor layers (8, 9) can be connected to external terminals via highly doped portions (4, 10), respectively. The semiconductor layers (8, 9) can modulate the phases of optical signals since the concentration of free carriers in the electric field region of the optical signals is modulated in an area in the vicinity of the contact surfaces of the semiconductor layers and the dielectric film (11) due to accumulation, removal, or inversion of the free carriers caused by electrical signals from the external terminals. At least one of the semiconductor layers (8, 9) has a width larger than the laminated portion, and at least one of the highly doped portions (4, 10) is formed outside the laminated portion.</p> |
