Frequency-dependent linewidth enhancement factor of optical injection-locked quantum dot/dash lasers

Combining theoretical and experimental studies show that optical injection strongly changes the behavior of the linewidth enhancement factor (αH-factor) and the FM-to-AM indices ratio (FAIR) in quantum dash/dot semiconductor lasers. In contrast to solitary lasers, both the αH-factor and the FAIR at low-frequency modulation are reduced by optical injection. At high modulation frequency, however, the phase-amplitude coupling characteristics are little influenced by optical injection.