In this paper, a new all-optical switching structure is proposed and analyzed. Switching is accomplished by embedded Kerr nonlinear rods in the coupling region of a photonic crystal directional coupler. We show that by modifying the supermodes dispersion curves, the switch length can be reduced 22% with respect to similar structures. Finite-Difference TimeDomain and Plane Wave Expansion methods...

We demonstrate that nonlinear directional coupler with special bending of waveguide axes can be used for all-optical switching of polychromatic light with very broad spectrum covering all visible region. The bandwidth of suggested device is enhanced five times compared to conventional couplers. Our results suggest novel opportunities for creation of all-optical logical gates and switches for po...

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...

We present simple and accurate relations for the study of parallel and curved tunable single-mode fiber directional couplers employing step-index or graded-index fibers. Analytical results for the various coupler parameters such as coupling coefficient, effective interaction length, tunability, and channel wavelength separation in directional coupler wavelength filters are presented. These resu...

We study, theoretically and experimentally, the evolution of optical waves with randomly-fluctuating phases in a spatially chirped nonlinear directional coupler. As the system crosses its linear resonance, we observe collective self-phase-locking (autoresonance) of all mutually-incoherent waves, each with its own pump, and simultaneous amplification until the pumps are exhausted. We show that t...

An all-fiber-ring resonator has been constructed using a single strand of single-mode optical fiber and a directional coupler. Derivation of the resonator finesse in terms of fiber and directional coupler parameters is given. A finesse of 80 has been achieved experimentally. Applications of such a fiber-ring resonator are discussed.

We suggest and demonstrate numerically that, by employing tapered waveguides in the geometry of a directional coupler, we can enhance dramatically the performance for optical switching of nonlinear plasmonic couplers operating at the nanoscale, overcoming the detrimental losses but preserving the subwavelength confinement. We demonstrate that, by an appropriate choice of the taper angle of the ...