Comparative analysis of various methods to reach the 1.3-µm emission in GaInNAs/GaAs QW VCSELs

Three methods to obtain in GaAs-based oxide-confined GaInNAs/GaAs quantum-well (QW) VCSELs an efficient emission of the 1.3-µm radiation have been analysed and compared with the aid of the comprehensive fully self-consistent model. In the tuned VCSEL, QW composition (high N content) and thickness are selected to tune the 1.3-µm emission which ensures low threshold currents. However, manufacturing of such N-rich GaInNAs layers and/or such thin QWs threatens with generation of structure defects or even cracking. The 1.3-µm emission may be also forced in VCSELs with lower nitride QW content by the cavity appropriately detuned with respect to the active-region gain spectrum. Such a detuned VCSEL exhibits excellent properties at elevated ambient temperatures whereas its operation at room temperature may be reached at the price of a very high lasing threshold only. Introducing inter-mediate layers of lower energy gaps on both QW sides also enables reaching the tuned 1.3-µm lasing emission in VCSELs with lower QW nitride content. However, this QW-modified VCSEL is more sensitive to temperature increases and its lasing operation is stopped at higher temperatures. Therefore it may be concluded, that a choice of the most appropriate active region structure depends on a particular VCSEL application.