Influence of Radiative Energy Transfer on the Thermal Behavior of Bonded InGaAs/GaAs Lasers

Temperature characteristics and thermal resistance of InGaAs/GaAs laser diode (LD) is investigated from below to beyond the lasing threshold. Spectrally-resolved emission measurements show that the heat generated in the active region is induced by the radiative energy transfer of free carriers. Below the lasing threshold, nonradiative recombination induces large heat generation in the active region. Beyond the lasing threshold, Joules heating due to the series resistance of the LD dominates the heating response. The dependence of the associated thermal resistance on different bonding configurations and its correlation with the output power is also discussed. Epi-side up and epi-side down bonding of LDs reduces the device temperature by ~ 30% and ~ 50%, respectively.