ABSTRACT
Threshold Current 359 12.6 1.3-gm GaInNAs/GaAs VCSELs 362 12.7 LASERS OPERATING AT WAVELENGTHS LONGER
THAN 1.3-gm 365 12.8 SUMMARY AND CONCLUSIONS 366
Acknowledgments 367 References
12.1 INTRODUCTION
A major commercial force driving the development of GaInNAs alloys is the need to develop semiconductor lasers on GaAs substrates that can operate in the 1.3-1.551.tm wavelength range, which is used for opticalfiber communications. For example, monolithic vertical-cavity surfaceemitting lasers (VCSELs), with their cheaper batch processing and simple optics, can be grown on GaAs. Of crucial importance to the operation of diode lasers is the value of the current density, Jth, that must be passed through the device in order to reach the required optical gain. Also, since the lasers must be able to operate over quite a wide temperature range, the variation of 7th with temperature is another important parameter. It is therefore extremely important to be able to quantify the electron-hole recombination mechanisms that lead to Jth and their variation with temperature. It should be emphasized that this does not just involve identifying which recombination mechanisms may be present, but also determining their relative magnitudes at the injected carrier density required by the lasing process.
