Semiconductor lasers with improved frequency modulation response

A frequency-modulated continuous wave semiconductor laser, comprising:

• a single mode laser cavity comprising a stack of semiconducting layers defining a transversal p-n junction and having a longitudinal light propagation direction;
• a plurality of electrodes each coupled to a corresponding section of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section inside of the single mode laser cavity;
• one or more DC sources each coupled to the electrodes associated with said amplification sections and operable to forward-bias the p-n junction above transparency so as to provide gain in the associated amplification sections;
• and
• one or more modulation signal sources each coupled to the electrodes associated with said modulation sections and operable to apply a modulation signal across said p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser, the one or more modulation signal sources comprise at least one AC current source configured to inject a modulated current accross the p-n junction in the modulation sections, the modulated current differing from the one modulation section to another;
• wherein each modulation section is operated in photovoltaic mode.