In this paper an improved dynamical model of a three-section distribut
ed Bragg reflector (TSDBR) laser that includes gain saturation effects
and mode competition is used to carefully analyze the tuning static c
haracteristics, the switching dynamics, and the optically-controlled f
requency conversion of the device. As a result, reasonable estimates o
f the switching times and insights into the device behavior are obtain
ed, together with curves showing the IM/FM frequency and modulation co
nversion.