Broadband lasing characteristics of a chirped InAs/InP quantum-dash laser

We investigate the temperature dependent spectral characteristics of an InAs multi-stacked quantum-dash-inwell laser. The multi-stack active medium optical transitions are dispersed by varying the thickness of AlGaInAs barrier layers. The analysis is carried out via a Fabry-Perot 700 μm long-cavity laser with a ridge width of 2 μm at different temperatures. A lasing bandwidth of <40 nm is observed at room temperature with total optical power of <150 mW. Moreover, broadening of lasing spectrum is observed with increasing the temperature, due possibly to a thermionic assisted emission and to optical pumping, enabling a full exploitation of the inhomogeneous optical transitions within the active region which indicates an increase in the available states in the active region. Therefore, proper optimization of the multi-stack active medium is required to fully utilize these optical transitions while maintaining high quantum efficiency, and proper bandgap engineering the device structure.