Switching and enhanced bistability in an asymmetric nonlinear directional coupler with a metamaterial channel

Coelho, A. G.; Queiroz, Alex Sander Barros; Silva, M. G. da; Lyra, M. L.; Sombra, A. S. B.

doi:10.1016/j.cnsns.2012.09.025

Cited by 15 publications

(8 citation statements)

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“…The notion of inhomogeneous nonlinearity is emerging as a distinct route for making alloptical devices such as switches, logic gates, and other signal processing devices [27][28][29][30][31][32][33][34][35]. As the name implies, the term inhomogeneous nonlinearity refers to the variation in the nonlinearity ( ) as a function of propagation coordinate .…”

Section: Introductionmentioning

confidence: 99%

“…In other words, the value of the nonlinear coefficient is not constant, but it varies as the light traverses through the device [ ( )]. From a theoretical standpoint, scientific works which deal with the switching dynamics of anti-directional couplers (ADCs) [31], and directional couplers (DCs) [28,29,35] with inhomogeneous nonlinear profiles are many. There seem to exist a few works dealing with the switching in a grating with inhomogeneous nonlinearity.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to the conventional FBG devices with the homogeneous nonlinearities [27], gratings with varying nonlinear profiles switch at higher or lower critical intensities depending on the profile used and the value of the inhomogeneous nonlinearity parameter ( ( )). Different kinds of nonlinear profiles exist in the form of linear, Gaussian, exponential, logarithmic, and so forth [28,29,31,34,35]. Judicious selection of the nonlinearity profile and manipulation of the inhomogeneous nonlinearity parameter are necessary for acquiring low-power AOS.…”

Section: Introductionmentioning

confidence: 99%

“…The same material with a wide range of nonlinear coefficients can be manufactured by varying the doping levels. It is possible to produce a fiber with an inhomogeneous nonlinear profile by suitably controlling the thickness, the density of the dopant, or dopant diffusion time [28,29,31,34,35]. Controlling of these parameters independently produces inhomogeneity in the linear RI profile ( 0 ).…”

Section: Introductionmentioning

confidence: 99%

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Inhomogeneous nonlinearity meets parity–time-symmetric Bragg structures: route to ultralow power steering and peculiar stable states

et al. 2022

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In the context of parity–time ( P T )-symmetric fiber Bragg gratings, tailoring the nonlinear profile along the propagation coordinate serves as a new direction for realizing low-power all-optical switches. The scheme is fruitful only when the nonlinearity profile will be either linearly decreasing or increasing form. If the rate of variation of the nonlinearity profile is high, the critical intensities fall below the input power of value 0.01 in the unbroken regime provided that the light launching direction is right. Nowadays, every new theoretical inception into the parity–time fiber Bragg grating (PTFBG) has started making sense of switching in the broken P T -symmetric regime, which was once believed to be the instability regime. When the inhomogeneous nonlinearity acts together with the broken P T symmetry and right light incidence, it leads to two peculiar settings. First, the switch-up intensities are ultralow. Second, the switch-down action takes place at zero critical intensities. Such optical bistability curves are unprecedented in the context of conventional gratings and found only in plasmonic devices and anti-directional couplers. Even though the nonlinearity is inhomogeneous, the ramp-like first stable states persist in the broken P T -symmetric regime, giving an additional indication that the broken PTFBG is closely associated with the plasmonic structures. In the existing PTFBG systems, the switching intensities are relatively higher in the broken regime. However, the proposed system records the lowest switching intensities in the broken regime. The reported intensities ( <Introductionmentioning

confidence: 99%