Optimization of 1.3 µm GaAs-based oxide-confined (GaIn)(NAs) vertical-cavity surface-emitting lasers for low-threshold room-temperature operation

In this paper, use of a comprehensive self-consistent optical–electrical–thermal–gain threshold model of oxide-confined GaAs-based (GaIn)(NAs)/GaAs quantum-well vertical-cavity surface-emitting diode lasers (VCSELs) is demonstrated. The model was developed to facilitate better understanding of the physics of operation of the above devices including the full complexity of the many interactions, in the volumes of the devices, between individual physical phenomena. Besides this, the model was applied in designing and optimizing such VCSELs for long-wavelength 1.3 µm second-generation optical fibre communication system use and for examining their anticipated continuous-wave (CW) room-temperature (RT) low-threshold performance. The influences of many construction parameters on device CW RT lasing thresholds and mode selectivity were investigated. Some essential design guidelines were proposed to support efforts of technological centres to produce low-threshold single-mode RT CW devices. In particular, the 1.5λ-cavity VCSELs have been found to exhibit lower RT CW lasing thresholds, whereas the 3λ-cavity ones offer better thermal properties: higher values of the parameter T 0 and single-fundamental-mode operation possible at higher temperatures. As expected, the desired stable RT CW single-fundamental-mode operation is possible in smaller VCSELs (with active-region diameters not exceeding 6 µm in the case of the 1.5λ-cavity VCSELs). A deliberate detuning of the lasing mode from the RT active-region optical peak gain towards higher wavelengths ensures better device operation at higher temperatures.