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...

we propose a new ring resonator side-coupled m-z interferometer all-optical switch throughthe pumped nonlinear directional coupler. by controlling pump power p to lead the coupler reflectivityr approaching to 1, the resonator finesse will be enhanced dramatically, and then the minimumswitching power in silica-based practice devices can be obtained. as a sample, we use a nonlinearcoupler made by...

in this paper a novel design of all-optical half-subtractor based on nonlinear directional coupler is proposed. by using four waveguides and appropriately adjusting the refractive indices and selecting the proper length of waveguides, halfsubtractor function can be obtained. the operation of this function is simulated by rsoft cad-layout (beamprop) simulator. the simulation results confirm the ...

Linear and nonlinear directional couplers are currently used in fiber optics communications. They may also play a role in multiphoton approaches to quantum information processing if accurate control is obtained over the phases and polarizations of the signals at the output of the coupler. With this motivation, the constants of motion of the coupler equation are used to obtain an explicit analyt...

In this paper a novel design of all-optical half-subtractor based on nonlinear directional coupler is proposed. By using four waveguides and appropriately adjusting the refractive indices and selecting the proper length of waveguides, halfsubtractor function can be obtained. The operation of this function is simulated by RSoft CAD-Layout (BeamPROP) simulator. The simulation results confirm the ...

In this paper a novel design of all-optical half-subtractor based on nonlinear directional coupler is proposed. By using four waveguides and appropriately adjusting the refractive indices and selecting the proper length of waveguides, halfsubtractor function can be obtained. The operation of this function is simulated by RSoft CAD-Layout (BeamPROP) simulator. The simulation results confirm the ...

We report on intensity-dependent switching in lithium niobate directional couplers. Large nonlinear phase shifts that are due to cascading detune the coupling between the coupler branches, which makes all-optical switching possible. Depending on the input intensity, the output could be switched between the cross and the bar coupler branches with a switching ratio of 1:5 and a throughput of 80%.

Absfrucf-A comprehensive analysis of the symmetric nonlinear directional coupler as a function of the excitation conditions is reported. The analysis is based on a coupled-mode technique in normalized (dimensionless) parameters, using the linear supermodes of the guiding structure, most of the results being derived from the Hamiltonian of the resulting nonlinear equations. The exchange of power...