An optical transmitter includes photonic integrated circuits configured to respectively output optical transmission signals in different wavelength ranges. A photonic integrated circuit may include emitters configured to emit beams having different wavelengths; drivers configured to respectively provide power to the emitters, and a wavelength division multiplexer configured to transmit the beams emitted by the emitters. A photonic integrated circuit may include a switch device that controls the drivers, and light detectors configured to detect intensities of the beams emitted from the emitters. The switch device may selectively operate at least one driver of the plurality of drivers based on information associated with intensities of the beams. The switch device may selectively operate a driver connected to an emitter, based on a determination that an intensity of a beam emitted by another emitter is less than a threshold intensity value.