Parametric analysis of semiconductor-doped glasses for all-optical switching

We use the basic physical parameters of semiconductor-doped glasses (SDG´s) to compute the dependence of their nonlinear index n₂ due to the bandgap resonant effect on pump intensity and to predict the power and length requirements of an all-optical SDG waveguide switch. The main conclusions are that (1) the pump and signal wavelengths should be in specific and different ranges to minimize the switching power and signal loss, (2) for CdSSe- and CdTe-doped glasses, n₂ is relatively small, (3) their power requirements are consequently quite high (2-100 W), although (4) much lower than in a comparable device operated near the half-bandgap. We provide evidence that this weak nonlinearity, compared to that of semiconductors in bulk, is due to the strong nonradiative recombination of carriers arising from the small size of the semiconductor microcrystallites. Projections indicate a reduction in switching power by up to a factor of 1000 by increasing the microcrystallite size, thus producing a slower (ns) but more power efficient switch