Design an All-Optical Combinational Logic Circuits Based on Nano-Ring Insulator-Metal-Insulator Plasmonic Waveguides

In this paper, we propose, analyze and simulate a new configuration to simulate all-optical combinational logic functions based on Nano-rings insulator-metal-insulator (IMI) plasmonic waveguides. We used Finite Element Method (FEM) to analyze the proposed plasmonic combinational logic functions. The analyzed combinational logic functions are Half-Adder, Full-Adder, Half-Subtractor, and Comparator One-Bit. The operation principle of these combinational logic functions is based on the constructive and destructive interferences between the input signal(s) and control signal. Numerical simulations show that a transmission threshold exists (0.25) which allows all proposed four plasmonic combinational logic functions to be achieved in one structure. As a result, the transmission threshold value measures the performance of the proposed plasmonic combinational logic functions. We use the same structure with the same dimensions at 1550 nm wavelength for all proposed plasmonic combinational logic functions. The proposed all-optical combinational logic functions structure contributes significantly to photonic integrated circuits construction and all-optical signal processing nano-circuits.

High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities

In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM) value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators.

A Plasmonic Temperature-Sensing Structure Based on Dual Laterally Side-Coupled Hexagonal Cavities

A plasmonic temperature-sensing structure, based on a metal-insulator-metal (MIM) waveguide with dual side-coupled hexagonal cavities, is proposed and numerically investigated by using the finite-difference time-domain (FDTD) method in this paper. The numerical simulation results show that a resonance dip appears in the transmission spectrum. Moreover, the full width of half maximum (FWHM) of the resonance dip can be narrowed down, and the extinction ratio can reach a maximum value by tuning the coupling distance between the waveguide and two cavities. Based on a linear relationship between the resonance dip and environment temperature, the temperature-sensing characteristics are discussed. The temperature sensitivity is influenced by the side length and the coupling distance. Furthermore, for the first time, two concepts—optical spectrum interference (OSI) and misjudge rate (MR)—are introduced to study the temperature-sensing resolution based on spectral interrogation. This work has some significance in the design of nanoscale optical sensors with high temperature sensitivity and a high sensing resolution.

All-optical logic gates based on nonlinear plasmonic ring resonators

A nonlinear plasmonic T-shaped switch based on a square-shaped ring resonator is simulated by the finite-difference time-domain numerical method. Three optical logic gates-a NOT, with one T-shaped switch, and AND and NOR gates, each with two cascaded T-shaped switches-are proposed. The nonlinear Kerr effect is utilized to show the performance of our proposed logic gates. The values of transmission at the ON and OFF states of NOT and NOR gates are 70% and less than 0.6% of the input lightwave, respectively, while these values for the AND gate are 90% and less than 30%, respectively.

A high throughput supra-wavelength plasmonic bull's eye photon sorter spatially and spectrally multiplexed on silica optical fiber facet

This paper presents a plasmonic bull's eye consisting of a micron-sized hole and a concentric nano-antenna metallic ring surrounded by periodic circular grooves on a thin gold film. The unique metallic nano-ring imbedded in the supra-wavelength-sized hole acts as an amplifying and filtering component to simultaneously provide a significantly lower spectral noise and a higher power transmission at the resonance wavelength, in comparison to prior sub-wavelength bull's eyes. Systematic numerical analyses based on finite-difference time-domain method were carried out to find the impacts of the structural parameters. Experimentally we integrated three proposed plasmonic structure on a cleaved facet of an optical fiber that can act as a spatially and spectrally multiplexed photon sorter. Transmission characteristics of the proposed devices were characterized in terms of the spectral response and signal to noise ratio. Potential applications of the fiber optic photon sorter were also discussed.