GaAs-based vertical-cavity surface-emitting lasers with GaSb quantum rings (QRVCSELs)

Vertical-cavity surface-emitting lasers (VCSELs) are small, fast, cheap lasers with a low-divergence circular-beam profile. They are ideally suited for sending signals down the optical fibres that are used to carry the vast amounts of information that we take for granted every day. VCSELs are already widely available for generating light in 600 to 1100 nm range for datacoms applications, e.g. relaying information around a datacentre, but, because of the distributed Bragg reflector (DBR) technology that is the key to their operation, they are invariably GaAs-based. This has limited their use in telecoms applications, which requires longer wavelengths (1260 nm to 1675 nm): it has proven difficult to generate a GaAs-based active region that emits at telecoms wavelengths. In this feasibility study we will assess the potential for commercially-viable, GaAs-based VCSELs, that can operate cooler-free at high-speed and at telecoms wavelengths, by exploiting the novel self-assembled GaSb quantum ring technology developed in Lancaster in the active region of the device.