Optical transmitter

An optical transmitter comprising:

• a laser comprising an optical output and configured to provide an optical signal to the optical output based on a control current;
• a control unit electrically coupled to the laser and configured to modulate the laser using the control current, wherein the control current comprises a direct current component and a temporally varying modulation component configured to cause a temporal variation of a wavelength of at least one spectral line in the optical signal;
• a semiconductor optical amplifier comprising an optical input and an optical output, wherein the optical input of the semiconductor optical amplifier is optically coupled to the optical output of the laser and the semiconductor optical amplifier is configured to receive the optical signal from the optical output of the laser, amplify the optical signal while operating in a saturation mode, and provide the amplified optical signal to the optical output of the semiconductor optical amplifier;
• and
• an optical fiber interface optically coupled to the optical output of the semiconductor optical amplifier.