Semiconductor device

A semiconductor device comprising:

• a semiconductor laser;
• a semiconductor laser driver which drives the semiconductor laser;
• an optical waveguide in which laser light emitted from the semiconductor laser propagates;
• an optical modulator which modulates the laser light propagating in the optical waveguide, based on first data transmitted as a first electrical signal, and converts the first electrical signal into an optical signal;
• and
• a monitor element which is disposed between the semiconductor laser and the optical modulator and converts the received laser light into a second electrical signal,
• wherein a light intensity of the laser light emitted from the semiconductor laser is adjusted by controlling the semiconductor laser driver based on second data transmitted as the second electrical signal.

A semiconductor device comprising:

• a semiconductor laser;
• a first optical waveguide in which laser light emitted from the semiconductor laser propagates;
• an optical modulator which modulates the laser light propagating in the first optical waveguide;
• a second optical waveguide which is branched from the first optical waveguide between the semiconductor laser and the optical modulator;
• and
• a monitor element which is connected to an end of the second optical waveguide and converts part of beams of the received laser light into a first electrical signal of a reverse phase,
• wherein the first electrical signal is superimposed on a second electrical signal transmitted from an outside, the second electrical signal is converted into a third electrical signal, and the optical modulator adjusts a light intensity of the laser light based on data transmitted as the third electrical signal and converts the third electrical signal into an optical signal.