Optical feedback effect on bistable laser diodes

The optical feedback effect on multi-section bistable laser diode characteristics, especially on light/current hysteresis, has been studied. A decrease in the bistable laser diode hysteresis width under optical feedback was observed for the first time. A theoretical analysis has been carried out by solving carrier density rate equations, combined with the light-field equation. The analysis shows that the observed hysteresis width decrease is due to the phase detuning, which is governed by the difference between the values of the α-parameters (line-width enhancement factors) in the gain section and the loss section.