1,721,013 research outputs found
Wideband multimode parametric amplification in optical fibers
No full textModulational instability in multimode fibers is theoretically and numerically investigated. A phenomenon of collective mode amplification is put in evidence, where all fiber modes are simultaneously amplified in a broad frequency band
Analytical approximations of the dispersion relation of the plasmonic modes propagating around a curved dielectric-metal interface
No full textWe find some useful and effective approximations of the dispersion relation of the fundamental surface plasmon wave propagating around a curved dielectric-metal interface. These estimations are valid even with a very small curvature radius, which is the case of interest for nano-optics applications, and are validated through the numerical solution of the characteristic equation of the curved interface
Complex dispersion relation of a double chain of lossy metal nanoparticles
No full textWe study the propagation characteristics of optical signals in waveguides composed of a double chain of metallic nanoparticles embedded in a dielectric host. We find that the complex Bloch band diagram for the guided modes, derived by the Mie scattering theory including material losses, exhibits strong differences with respect to the previously studied single chain. The results of the model are validated through the finite element solution of the Maxwell equations
All-optical sampling and magnification based on XPM-induced focusing
No full textWe theoretically and experimentally investigate the design of an all-optical magnification and sampling function free from any active gain medium or additional amplified spontaneous noise emission. The proposed technique is based on the co-propagation of an arbitrary shaped signal together with an orthogonally polarized intense fast sinusoidal beating within a normally dispersive optical fiber. This process allows us to experimentally demonstrate a 40-GHz sampling operation as well as an 8-dB magnification of an arbitrary shaped nanosecond signal around 1550 nm in a 5-km long optical fiber. The experimental observations are in good agreement with numerical and theoretical analysis
Strategies for wideband light generation in nonlinear multimode integrated waveguides
No full textIn this paper we discuss two strategies to achieve wideband light generation through intermodal nonlinear parametric processes in multimode integrated waveguides. We outline how the interplay among intermodal interactions and high dispersion may lead to the generation of light characterized by substantial power spectral density if compared to supercontinuum sources. These results are valid independently of the waveguide material; however, our numerical simulations focus on silicon waveguides, which are nowadays at the core of integrated photonics. The long-term vision is that by exploiting an adequate number of intermodal processes, widely tunable radiation having high-power spectral density can be generated in a broad portion of the transparency window of silicon
Nonlinear polarizers based on four-wave mixing in high-birefringence optical fibers
No full textParametric amplification or four-wave mixing in high-birefringence optical fibers may be exploited to implement a novel type of nonlinear polarizer. Such a device leads to the simultaneous amplification, frequency conversion, and repolarization of both signal and idler waves along one of the principal birefringence axes of the fiber, independently of the pump, signal, and idler input state of polarization, power, and frequency detuning. We discuss the conditions for the observation of polarization attraction in fiber optics parametric amplifiers operating with a pump in either the normal or the anomalous dispersion regime
Polarization chaos and random bit generation in nonlinear fiber optics induced by a timedelayed counter-propagating feedback loop
No full textWe demonstrate that the nonlinear interaction in an optical fiber between an incident beam and its backward delayed replica leads to a chaotic dynamics of its output polarization state, enabling a powerful scrambling process that can be exploited for generates random bits.</p
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