we will present a detailed investigation of intersubband transitions process in core-multi shells quantum dots. the confined wave functions and eigenenergies of electrons in quantum dots have been calculated under the effective-mass approximation by solving a three-dimensional schrodinger equation. excellent dependence is found between size effects, time relaxation and degenerate four wave mixi...

in this paper a novel all-optical logic nand, nor and xor gate based on nonlinear directional coupler theory is demonstrated. we use the identical structure which contains three waveguides, for designing these gates; the only difference however, is the power of inputs light beam. in other words, while a beam with 4 w/μm in power considered as logical one, the output is nand gate and if a beam w...