Temperature dependent lasing characteristics of multi-stacked quantum dot lasers

Temperature dependence of self-formed quantum dot lasers with a multi-stacked dot layer has been investigated in detail. Lasers oscillating at different subbands exhibit different behaviors against temperature change both in the spectral characteristics and the threshold current. A discontinuous shift of lasing wavelength from the second subband to the ground state is observed with lowering temperature, which is strongly related to emission efficiency of quantum dots and thermal excitation of carriers to higher-order subbands. High characteristic temperature over 300 K has been achieved in a laser with high-reflection coating on both facets in the temperature range 60-200 K. (C) 1997 American Institute of Physics.