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 (VSA) 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 ns at zero bias. tau(a) is found to decrease rapidly for higher reverse biases and a minimum of tau(a) = 0.4 ns is interpolated for flatband conditions. We explain the dependence of the carrier lifetime on V-SA via the modification of the quantum-confined Stark effect. (C) 2011 American Institute of Physics. [doi:10.1063/1.3591977]