Title :
Scaling behavior of bipolar cascade VCSELs
Author :
Knödl, T. ; Straub, A. ; Golling, M. ; Michalzik, R. ; Ebeling, K.J.
Author_Institution :
Dept. of Optoelectron., Ulm Univ., Germany
Abstract :
We present theoretical and experimental results on the scaling properties of bipolar cascade vertical-cavity surface-emitting lasers with respect to active region stacking and out-coupling mirror reflectivity. The measurement results at around 980-nm wavelength confirm the theoretically expected behavior of an almost linear increase in slope efficiency and a reduction in threshold current density with the number of stages. A three-stage laser shows a differential quantum efficiency of 128% in continuous-wave operation at room temperature. For the threshold current density, we obtain a decrease from 3.75 kA/cm/sup 2/ for the conventional VCSEL to about 1.2 kA/cm/sup 2/ for a three-stage device. Such multi-diode cascade VCSELs are highly interesting for optical links, analog systems, and high-power applications.
Keywords :
current density; laser mirrors; reflectivity; surface emitting lasers; 980 nm; active region stacking; analog systems; bipolar cascade VCSELs; continuous-wave operation; differential quantum efficiency; high-power applications; multi-diode cascade VCSELs; optical links; out-coupling mirror reflectivity; room temperature; scaling behavior; slope efficiency; three-stage laser; threshold current density; Density measurement; Laser theory; Mirrors; Optical surface waves; Quantum cascade lasers; Reflectivity; Stacking; Surface emitting lasers; Threshold current; Vertical cavity surface emitting lasers;
Journal_Title :
Photonics Technology Letters, IEEE
