Thermal performance of 1.55μm 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 I_th is due to non-radiative 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 non-radiative 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.