Extended cavity lasers in InGaAs-InGaAsP and InGaAlP-GaAs multi-quantum well structure using a sputtered SiO2 technique

Sputtering a thin layer of SiO₂ (≈200 nm) followed by high temperature annealing has recently been found to be very promising in promoting quantum well intermixing. The intermixing is thought to be due to point defects generated by the sputtering plasma diffusing through the material during a subsequent high temperature anneal. The process uses simple low-cost techniques, and is extremely reproducible and reliable. In this paper we describe the technique using the sputtered SiO₂ and subsequent high temperature annealing, either by rapid thermal annealer (RTA) or CW Nd:YAG laser operated at 1.064 μm. Differential blue shifts of up to 60 meV and 120 meV have been obtained for InGaAs/InGaAsP and GaInP/AlGaInP material systems. Extended cavity lasers have been fabricated and characterised for both material systems