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...

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...

The challenging goal of realizing on-chip quantum circuits in which spins are interfaced with photons that are then routed, processed and detected has triggered significant research efforts over the past decades [1]. InGaAs/GaAs quantum dots (QDs) integrated in photonic crystal (PhC) circuits are one of the most advanced technologies in this direction [2]. Most of the work has focused on Strans...

We suggest a novel scheme for multistep cascaded parametric processes based on a periodically poled nonlinear directional coupler and derive the conditions for simultaneous phase matching of the second-harmonic generation and sum-frequency mixing processes. We predict an efficient wavelength conversion by the cascaded third-harmonic generation from the third optical communication window (1.53-1...

We theoretically investigate the interaction of a single quantum dipole with the modes of a fiber-coupled semiconductor waveguide. Through a combination of tight modal confinement and phase-matched evanescent coupling, we predict that approximately 70% of the dipole's emission can be collected into a single-mode optical fiber. We further show that the dipole strongly modifies resonant light tra...

The design of grating-assisted, channel waveguide, codirectional couplers is demonstrated using the Gel’fand-Levitan-Marchenko inverse scattering method. Weighted coupling coefficients are computed from rational function expressions for the desired wavelength response. Approximate formulas are derived which relate the waveguide and grating geometries to the computed coupling coefficients. The t...

A coupler based on silicon spherical microcavities coupled to silicon waveguides for telecom wavelengths is presented. The light scattered by the microcavity is detected and analyzed as a function of the wavelength. The transmittance signal through the waveguide is strongly attenuated (up to 25 dB) at wavelengths corresponding to the Mie resonances of the microcavity. The coupling between the m...

For high-power operation of charged particle rf accelerators, the input coupler windows must withstand enormous stresses due to charging induced by the highenergy charged particle beam passing by and high rf power passing through. Since most couplers use a single coupling aperture, harmful asymmetrical rf kick on the beam at the coupler-cavity interface exists. If this problem is solved by dual...