Evaluating the continuous-wave performance of AlGaInP-based red (667 nm) vertical-cavity surface-emitting lasers using low-temperature and high-pressure techniques

By measuring visible AlGaAs/AlGaInP vertical-cavity surface-emitting lasers (VCSELs) and similar edge-emitting lasers (EELs) as a function of temperature and pressure, we study the contributions of electron leakage and gain-cavity detuning on the threshold current, Ith, of VCSELs. In the EELs, leakage accounts for ∼20%Ith at room temperature, rising to ∼70%Ith at 80 °C. Similarly, leakage accounts for almost all of the increase in the VCSEL Ith above −100 °C and limits the cw output power. At low temperature or high pressure, however, the VCSEL Ith increases sharply due to misalignment of the gain peak to the high-energy side of the cavity mode. Under normal operating conditions, carrier leakage has the greatest effect on the VCSELs with gain-cavity detuning only becoming important at very low temperatures.