Optical modulator and optical transmitter

An optical transmitter, comprising:

• a semiconductor laser that outputs continuous light;
• and
• an optical modulator that modulates the continuous light from the semiconductor laser;
• the optical modulator including:
• an optical waveguide core made of a semiconductor material;
• an electrode;
• and
• a plurality of channels made of a semiconductor material doped in an n type or a p type and electrically connecting the optical waveguide core and the electrode to each other;
• the plurality of channels being provided in a spaced relationship from each other along a propagation direction of light;
• the optical waveguide core including a doped region doped in the n type or the p type and a non-doped region, the doped region and the non-doped region being disposed alternately along the propagation direction of light;
• and
• each of the plurality of channels being connected to the doped region;
• the plurality of channels being provided periodically in a fixedly spaced relationship from each other in the propagation direction of light;
• a wavelength of the continuous light outputted from the semiconductor laser being set to a wavelength in the proximity of a band edge on the longer wavelength side of a stop band of a transmission spectrum of the optical modulator.