Thermal Characteristics of 1.55- $\mu$ m InGaAlAs Quantum Well Buried Heterostructure Lasers

We have investigated the threshold current I_th and differential quantum efficiency as the function of temperature in InGaAlAs/InP multiple quantum well (MQWs) buried heterostructure (BH) lasers. We find that the temperature sensitivity of ith is due to nonradiative recombination, which accounts for up to ˜80% of J_th at room temperature. Analysis of spontaneous emission emitted from the devices show that the dominant nonradiative recombination process is consistent with Auger recombination. We further show that the above threshold differential internal quantum efficiency η_i is ˜80% at 20°C remaining stable up to 80°C. In contrast, the internal optical loss, α_i, increases from 15 cm^-1 at 20°C to 22 cm^-1 at 80°C, consistent with inter-valence band absorption (IVBA). This suggests that the decrease in power output at elevated temperatures is associated with both Auger recombination and IVBA.