Design and optimisation of MBE-grown GaAs-based "W"-lasers for O-band applications

Type-II GaInAs/GaAsSb "W"-active regions offer the potential for greater control over the temperature sensitivity of semiconductor lasers operating in the near-IR. In this paper we explore the theoretical design space available using "W"-QWs and discuss the interplay between active region design choices and waveguide optimisation, highlighting the importance of simultaneous optimisation in these systems. We demonstrate the molecular beam epitaxy growth of GaAs-based "W"-lasers emitting around 1250 nm, achieving a room temperature threshold current density of 480±10 A/cm². These initial results demonstrate the promising potential of "W"-lasers for energy-efficient O-band applications in data communications networks.