| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor Mach-Zehnder optical modulator whose optical loss is small and having small phase adjustment means.SOLUTION: In a semiconductor Mach-Zehnder optical modulator, an electrode 105 for phase modulation that applies a modulation signal and an electrode 106 for phase adjustment that applies a DC bias voltage are formed on two arm waveguides configuring a Mach-Zehnder interferometer. An n-type InP clad layer 101, a non-dope semiconductor core layer 102, a non-dope InP clad layer 103, and a p-type InP clad layer 104 are sequentially laminated. However, the non-dope InP clad layer 103 is not provided in a phase adjustment region immediately below the electrode 106 for phase adjustment or made to be in a state where a thickness is thinner than other region.SELECTED DRAWING: Figure 1 |
