Fabrication of bandgap tuned lasers in GaAs/AlGaAs structure using sol-gel SiO₂ induced quantum well intermixing

Quantum well intermixing (QWI) is a promising technology for the fabrication of photonic integrated circuits (PICs). In this paper, we report the development of a new QWI process using undoped and Er-doped SiO₂ dielectric caps prepared using sol-gel technique. A differential bandgap shift of as large as 83 meV have been observed from samples intermixed with Er-doped and undoped SiO₂ respectively. Broad area gain guided lasers have been fabricated from the as-grown and samples with bandgap tuned to different degrees using undoped and Er-doped SiO₂. Lasers fabricated from the as-grown, undoped and Er-doped SiO₂ samples showed lasing wavelengths of 865 nm, 850 nm and 835 nm respectively. Compared to the 865 nm, the threshold current of the 850 nm and 835 nm wavelength lasers were found to increase by 5% and 9.5% respectively. The slope efficiencies from these lasers were found to exhibit only small change compared to the as-grown lasers. These results imply that the quality of the material remains relatively high after intermixed using sol-gel SiO₂ induced QWI technique.