Patent ID: 11947237
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. A semiconductor Mach-Zehnder optical modulator, comprising:
an optical waveguide formed on a substrate;
a dielectric layer on the substrate;
an input side lead-out line on the dielectric layer, the input side lead-out line including a first end to which a modulation signal is input;
a phase modulation electrode line on the dielectric layer along the optical waveguide, the phase modulation electrode line including a first end connected to a second end of the input side lead-out line;
an output side lead-out line on the dielectric layer, the output side lead-out line including a first end connected to a second end of the phase modulation electrode line;
an electrode configured to apply a modulation signal to the optical waveguide, the modulation signal propagating through the phase modulation electrode line; and
an attenuator configured to attenuate the modulation signal in a lower layer under the output side lead-out line or an upper layer over the output side lead-out line, wherein the attenuator includes at least one semiconductor layer that is disposed intermittently along the output side lead-out line in the lower layer under the output side lead-out line, the at least one semiconductor layer being n-type or p-type.