1,720,987 research outputs found
Multilayer optical routing by means of vertical directional coupler with long range surface plasmons
No full textAnalysis of a phase shifter based on a slot polymeric waveguide with liquid crystal cladding
No full textWe numerically investigated a phase shifter based on a polymeric platform by using two different approaches. The device consists of a polymeric slot waveguide covered with an organic liquid crystal cladding, which is a promising configuration for the implementation of polymeric waveguide systems for computation, communication and sensing. Two different nematic liquid crystals have been considered, E7 and 5CB. At first, we have indirectly computed the phase shift through a combination of 2D Finite Element Method with index ellipsoid theory. Then, we have investigated the signal propagation by means of 3D Finite Difference Time Domain Method, which allowed to obtain also the intrinsic propagation loss of the structure and the materials. Although each approach introduces specific approximations and requires different resources, both give similar results and confirm the excellent quality of the device, namely low propagation losses and relevant phase shifting capability
All-optical and logic gate based on semiconductor optical amplifiers for implementing deep recurrent neural networks
No full textThe development of optical logic gates is a key
factor for enabling next generation of computations in the
context of Deep Learning and Quantum Computing. In this
work, we introduce a scheme for the implementation of an alloptical
AND logic gate, which makes use of semiconductor
optical amplifiers (SOA) in cross-phase modulation
configuration combined with an all-optical XOR gate. Our
analysis includes a realistic model of SOA, which considers
also the phase and the delay of the signals. We prove that our
scheme allows us to obtain almost ideal transitions in 3 out of
the 4 situations in a 2-bit logic, with any SOA. The remaining
combination shows a reduction of extinction ratio, which can
still be improved with better tuning of SOAs
Optical properties of a waveguide-fed plasmonic nano-array through approximated scattering theory
No full textWe analyze the optical scattering properties of an array of Au nano-cylinders fabricated upon an ion-exchanged waveguide. The integrated systems is considered for fluoroscopy and Raman spectroscopy. Absorption, scattering and extinction have been calculated through a combination of Finite Difference Time Domain (FDTD) method and scattering theory. While a portion of the excitation signal interacts with the array, the remaining part flows through the waveguide, enabling areas within the simulation box that complicate the calculation through standard procedures. Our analysis includes adjustments and approximations addressing this issue and making full use of computational capabilities of FDTD
Analysis on vertical directional couplers with long range surface plasmons for multilayer optical routing
No full textCoupling efficiency enhancement between SU-8 waveguides and plasmonic nanostructures through indium tin oxide thin films
No full textWe present an optical analysis of the light coupling between a SU-8 polymer waveguide and a nano-cylinder surface array, for biosensing applications with scattering-induced fluorescence. The coupling efficiency was studied in the 490-590 nm range using Finite Difference Time Domain (FDTD) method and scattering theory. We modeled thin films of indium tin oxide (ITO) buffer layers with different thicknesses to evaluate the behavior of the device in a sandwich configuration. We found that ITO enhances the waveguide-array coupling efficiency up to 5 times
Array of plasmonic vivaldi antennas coupled to silicon waveguides for wireless networks through on-chip optical technology - WiNOT
Full text linkOptical technology applied to on-chip wireless communication is particularly promising to overcome the performance limitations of the state-of-the-art networks on-chip. A key enabling component for such applications is the plasmonic antenna coupled to conventional silicon waveguides, which can guarantee full compatibility with standard optical circuitry. In this paper, we propose an antenna array configuration based on tilted plasmonic Vivaldi antennas coupled to a silicon waveguide. The details of the single antenna and of the array design are reported. The radiation characteristics of the array are suitable for on-chip point-to-point communication, i.e. in-plane maximum gain of 14.70 dB for an array with five antennas. The array exploits a travelling wave feeding scheme and, therefore, is compact in size (about 3.5 μm x 8.7 μm)
Planar plasmonic bean-Like nano structures for high dichroic filtering: theory, fabrication and esperiment
No full text
Photonic devices with periodic nanostructures and plasmonic metasurfaces
No full textIn this work we present the potentialities of a class of metasurfaces based on Titanium nanocommas that features a relevant circular dichroism, a highly sought-after characteristic in sensing applications for photonic devices. The numerical results reveal promising values of dichroism in ultraviolet and visible frequencies, which further validates the use of Titanium for this type of devices. The variations of the performances descending from the superficial oxidation of the metal are reported, together with a discussion on details, results and guidelines from the fabrication processes
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