THEORYOFTHENONLINEARALL-OPTICAL LOGICALGATESBASED ONPBGSTRUCTURES

Inourwork, weshowthat photonic bandgap (PBG) systems containing nonlinear insertions areof interest forpossible applications astheall-optical adders andlogical gates. Twoprincipal schemes ofanall- optical adder based onthecombined ID-3D PBGmaterials containing optically nonlinear layers arediscussed. Duetotheelectromagnetic spectra nonlinear dependence onthelight signal intensity, thereflection properties of thesystem change significantly forchosen operation frequencies. Thephotonic structure behavior withchanging intensity isinvestigated for afewsystems consisting ofaperiodically layered structure covered with anoptically nonlinear material anda3Dopal PBGstructure. Thelatter plays therole ofamotherboard controlling and directing thesignals after thelogical trnsformation. Theoretical estimations oftheadder cell parameters are madefor Si/SiO2 andGaAs/AlAs photonic crystals covered with layers madefrom nonlinear doped glasses. The ideology ofangular signal processing isdeveloped. Itisshown that theangular-frequency diagram contains extremely sensitive areas inside thetotal reflection range, where theweaknonlinearity leads todramatic change inlight reflection andtransmission. Bothsolitary local modes andpure band modes areconsidered. For256-digit capacity theadder body hastoconsist of32768 cells connecting byoptical channels inthebothschemes. In summary, wediscuss somegeneral problems of"all-optical" signal processing, mechanisms ofnonlinear signal transformation andtheoptical negative differential resistance areas existence, heating, energy losses andenergy redistribution channels andgeometry factors.