Abstract

Optically-pumped, vertical external cavity semiconductor lasers (VECSELs) offer the intriguing possibility of generating high power, high brightness (near TEM₀₀), wavelength agile laser sources for a broad scope of applications. However, these devices are particularly susceptible to thermal shut-off at increased pump levels. The design parameter space of the complex semiconductor sub-cavity (resonant periodic gain (RPG) and high reflectivity DBR stack) making up the active mirror in a two mirror cavity) is enonnous rendering a trial and error approach to designing such lasers as essentially useless. Using a fully microscopic approach to calculating all of the critically important ingredients of the semiconductor optical response, we recently demonstrated the first closed-loop design and prediction of the L-I characteristic for an electrically-pumped low power InGaPAs 1.3 μm edge emitter without resorting to the use of free fit parameters¹. This microscopic quantum approach rigorously computes the low-density photoluminescence (PL) spectra (wafer diagnostic), inverted semiconductor gain (and refractive index) spectra, radiative (spontaneous) and Auger recombination losses for the specific QW structure. The only free parameters remaining are the cavity losses (intrinsic and mirror). In reference 1, the intrinsic losses were measured via cut-back experiments removing all adjustable parameters.

© 2007 IEEE