Dynamics of symmetrical mode beating in complex coupling two-section DFB lasers

Abstract

The effect of gain/loss coupling on the modal dynamics of weakly-coupled self-pulsating two section DFB lasers is studied in detail. A purely symmetrical mode-beating regime exists for imaginary coupling values between − 5% and 12.5%. The minimum required static detuning, the modulation index, and the tuning range of the predicted self-pulsations are sensitive to the magnitude of the gain/loss coupling. For the 10% gain-coupled DFB laser above 90% modulation index is predicted for self-pulsations between 34% and 123 GHz. For the 5% loss-coupled DFB laser above 50% modulation index is predicted for self-pulsations between 27 and 155 GHz.