Amplitude modulation of an injection-locked semiconductor laser for heterodyne-type optical communications

A direct amplitude-modulation technique of semiconductor lasers featuring good frequency-modulation-component suppression was developed for ASK heterodyne optical communications. A slave laser strongly injection-locked by a highly stabilized master laser is directly modulated through the driving current. The signal is then demodulated by optical heterodyning. It has been shown that the frequency-modulation component of the slave laser is effectively suppressed by the injection locking.