Temperature dependence of electroabsorption dynamics in an InAs quantum-dot saturable absorber at 1.3 μm and its impact on mode-locked quantum-dot lasers

We report temperature-dependent absorption recovery times in an InAs p-i-n ridge waveguide quantum-dot modulator under low reverse bias, investigated via subpicosecond pump-probe measurements. The measured decrease in absorption recovery time with increasing temperature (293-319 K) is in excellent agreement with a thermionic emission model. A similar trend in pulse duration with increasing temperature is also observed from a two-section mode-locked quantum-dot laser fabricated from a similar epitaxial structure. These measurements confirm the key role of the absorber recovery time in the reduction in the pulses generated by two-section mode-locked quantum-dot lasers, both at room and elevated temperatures. © 2010 American Institute of Physics.