Optical bistability in InGaN-based multisection laser diodes

Optical bistability is observed in cw-operating InGaN-based laser diodes including a saturable absorber (SA) section. The dependence of the light-current hysteresis on the SA section length and reverse bias $\left(V_{\text{SA}}\right)$ has been studied. An analytical approach is developed to estimate the carrier lifetime ${\tau }_a$ in the SA section from the measurements of the hysteresis width, which leads to ${\tau }_a=1.9\text{ns}$ at zero bias. ${\tau }_a$ is found to decrease rapidly for higher reverse biases and a minimum of ${\tau }_a=0.4\text{ns}$ is interpolated for flatband conditions. We explain the dependence of the carrier lifetime on $V_{\text{SA}}$ via the modification of the quantum-confined Stark effect.