The present article deals with device physics and modeling of an Hg<sub>0.28</sub>Cd<sub>0.72</sub>Te wide-area electron-initiated avalanche photodiode, with main input data extracted from first principles electronic structure codes. Due to the large dimensions of 30 μm x 30 μm x 11 μm a method which combines Monte Carlo transport simulation in the active multiplication layer with ‘weak conduction’ modeling in the charge carrier exit paths is introduced. Consequences resulting from adding perturbative, non-self-consistent small-signal analyses upon a self-consistent, large-signal background bias simulation are briefly examined. Likewise, the issue of ambipolar versus independent electron-hole transport in the absorption layer is discussed. We investigate the effects of alloy scattering on avalanche gain and compare alloy scattering rates used in some recent studies. Alloy scattering is for this particular device and model shown to increase the gain by more than an order of magnitude at typical bias voltages.
N-on-1 LIDT measurements were performed on ytterbium doped preforms used to make high peak power fiber amplifiers. Damage measurements were complicated by large index of refraction changes across the preforms. These difficulties were overcome by monitoring the beam profile before and after the samples and by only taking data where the transmitted beam was not significantly distorted. Single and 1000 shot data suggest slight laser conditioning of the preforms and rule out laser fatigue in the doped cores and surrounding fused silica. At 1064 nm, inside the emission spectra, there seemed to be little influence of the Yb dopant concentration on the measured LIDT.