Optimization of Single-Mode Photonic-Crystal Results in Limited Improvement of Emitted Power and Unexpected Broad Range of Tuning

This paper provides a numerical analysis of the influence of photonic crystal etching depth on the confinement factor, slope efficiency, emitted power and tuning range of single mode VCSELs. Several mechanisms were used to determine the level of power emission, namely: selective leakage, thermal focusing, the waveguide effect induced by the photonic-crystal, gain spectrum red shift, and its maximum reduction with the increase of driving currents. We show that careful design of the photonic crystal allows for a 10% increase in the emitted power of a single-mode regime and for a broad range of steering currents from 5 to 50 mA. Such attributes support tuning of a single-mode emission beyond the 20 nm spectrum range.