SEMICONDUCTOR OPTICAL MODULATOR, SEMICONDUCTOR OPTICAL INTEGRATED DEVICE, AND METHOD FOR MANUFACTURING THE SAME

摘要

Provided is a semiconductor optical modulator having a two-step mesa type optical waveguide and comprising a first clad layer (101), a mesa type core layer (102) formed on the first clad layer (101), and a second clad layer (103) of a mesa structure formed on the core layer (102) and having a mesa width smaller than the mesa width of the core layer (102). The two-step mesa type optical waveguide comprises a multimode optical waveguide area to or into which an electric field is applied or a current is injected, and a single mode optical waveguide area to or into which no electric field is applied nor no current is injected. If it is assumed that the mesa width of the core layer in the multimode optical waveguide area is Wmesa1 and the mesa width of the core layer in the single mode optical waveguide area is Wmesa2, Wmesa1 is greater than Wmesa2 (Wmesa1 > Wmesa2).