Temperature dependence of gain saturation in multilevel quantum dot lasers

The temperature dependence of quantum dot (QD) optical gain is analyzed using a multilevel model and compared with experiment. The maximum gain is found to have a surprisingly strong temperature dependence that causes level switching and can limit laser performance in QD lasers. The model based on multiple discrete levels elucidates general design criteria that should be satisfied to obtain a stable threshold versus temperature in QD lasers. Good agreement is obtained between calculations and experiment for level switching in 1.3-/spl mu/m QD lasers.