Experimental investigation of evolution of dynamics in short-resonant-cavity DFB laser with optical feedback

We conducted experiments to investigate the evolution of dynamics in short-resonant-cavity distributed feedback laser subject to optical feedback. Results reveal that the transition of the laser into chaos involves a regular switching between the stable state and quasi-periodic state. When exiting the chaotic state, the laser exhibits a switching between stable state and chaotic state, ultimately evolving into feedback locking. A new dynamic evolution path of the DFB laser has been proposed: stable state → switching between the stable state and quasi-periodic state → quasi-periodic state → chaotic state → switching between stable state and chaotic state → feedback locking. The influences of feedback strength on the duty cycle of quasi-periodic oscillation are examined. Moreover, a mapping of dynamics with respect to feedback strength and bias current is presented.