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We proposed an effective approach to enlarge the slow light bandwidth and normalized-delay-bandwidth product in an optimized moiré lattice-based photonic crystal waveguide that exhibits intrinsic mid-band characteristics. A flatband corresponding to a nearly constant group index of 34 over a wide bandwidth of 82 nm centered at 1550 nm with near-zero group velocity dispersion was achieved. A large normalized-delay-bandwidth product of 0.5712 with a relative dispersion of 0.114%/µm was obtained, which is a significant improvement if compared with previous results. Our results indicate that the photonic moiré lattice waveguide could advance slow light applications.

We present a single-layer, transmissive metalens for focusing the orthogonal polarization components of incident light to two independent focal spots without affecting the initial orthogonal polarization states. To produce the required phase profile, the cross-shaped nanorod, as the unit cell of the metalens, is developed to support arbitrary combinations of two independent phase shifts (0- $2\pi$ ) of transverse electric and transverse magnetic polarized light. A deep neural network is trained to generate the design parameters of each unit cell efficiently and accurately. The metalens is simulated with finite-difference time-domain method and good agreements are observed comparing with theoretical prediction. This work provides a new solution to multi-foci metalens and polarization beam splitter and may find potential applications in deep sensing, holography, information encryption and display.

Modified near-ballistic uni-traveling-carrier photodiodes with improved overall performances were studied theoretically and experimentally. A bandwidth up to 0.2 THz with a 3 dB bandwidth of 136 GHz and large output power of 8.22 dBm (99 GHz) under the −2V bias voltage were obtained. The device exhibits good linearity in the photocurrent-optical power curve even at large input optical power, with a responsivity of 0.206 A/W. Physical explanations for the improved performances have been made in detail. The absorption layer and the collector layer were optimized to retain a high built-in electric field around the interface, which not only ensures the smoothness of the band structure but also facilitates the near-ballistic transmission of uni-traveling carriers. The obtained results may find potential applications in future high-speed optical communication chips and high-performance terahertz sources.

We systematically investigated graphene-based slot and multi-slot waveguides. A tri-slot waveguide which significantly enhances the light-graphene interaction was experimentally demonstrated with low insertion loss. By integrating a dual-layer graphene h-BN heterostructure on the tri-slot waveguide, a high efficiency modulator is designed, which combines the advantages of high modulation efficiency (0.376 dB/μm), low insertion loss (0.01 dB/μm), large modulation bandwidth (∼0.13 THz) and low power consumption (∼0.128 pJ/bit). Our work may promote the development of future high efficient graphene-based optical devices.

Electromagnetically induced transparency like effect, which can form a sharp transmission window within a broad spectrum, has been widely studied due to its potential in many optical devices. In this work, unlike traditional couple-ring resonator structure, we propose a new scheme to achieve electromagnetically induced transparency using only one hole-ring resonator. Thus, the proposed scheme can greatly miniaturize the device. At the wavelength of about 1550 nm, the structure can form multiple transparency windows and can behave as a refractive index sensor with high resolution, the figure of merit can reach larger than 530. The proposed scheme can pave the way for many practical applications such as optical sensors, optical switches and slow light devices.

Interconnection of wide-area microgrids encounters a lot of challenges in energy management. Energy interaction among microgrids requires more extensibility and flexibility in communication and decision-making compared to energy management of a single microgrid. To address the problem, two distributed interaction algorithms for both islanded and grid-connected modes are proposed here, where price signal motivates aggregators to adjust power consumption and generation. Privacy-preserving gossip algorithm is designed to avoid disclosing local privacy in islanded interaction. Demand response (DR), as an important means of interaction, can optimize resource distribution and realize virtuous and stable market operation in grid-connected mode. Perturbation primal-dual sub-gradient method is therefore designed to optimize distributed demand response (DDR) considering global predetermined inequal constraints. Finally, taking an actual multiple-microgrid system as an example, simulation verifies the effectiveness and robustness under communication uncertainties.

A number of valid possible arrangements of renewable energy sources (wind turbines, solar photovoltaics) with energy storage systems (electrochemical storage, fuel cell, battery) for the large-scale electric grid system (26 GW) are explored in this paper. There are two core motivations for choosing such arrangements. First, the same type of renewable resources located at a single site have high fluctuation, so we model various type of renewable resources located at various locations to have lesser fluctuations accompanied with relatively compact energy storage systems. The second incentive is to find the true minimum cost combination, excluding subsidies and relaxation in taxes for governments. This study includes the whole year (hourly, 8760 h in total) electric load and related weather elements. It is found that the least cost combinations require excessive generation capacity, diverse renewable generation resources and energy storage techniques, which would meet the load requirements and have less carbon emissions.

Inspired by the recent development of graphene, we propose and experimentally demonstrate a novel metasurface, namely, spoof surface plasmonic graphene, for controlling the transports and emissions of electromagnetic waves. Similar to graphene, at the corners of the Brillouin zone for our designed metasurface, two bands of spoof surface plasmon polaritons (SSPPs) linearly touch together, forming Dirac-like cones. In the experiments, we directly observed the Dirac cones in the momentum space by using near-field scanning. When the frequency is changed from the lower cone to the Dirac point and to the upper cone, the corresponding SSPPs’ transport on the metasurface shows negative group velocities, pseudodiffusion characteristics, and positive group velocities, respectively. The emission of the SSPPs to the air shows a transition of the wavefront from a concave to flat and finally to convex. The metasurface proposed here may find many potential applications in directional antennas, waveguide, diffusion-like transport, focusing and imaging devices, and integrated spoof plasmonic circuits.

A decentralized self-discipline scheduling strategy based on virtual leader agents is proposed for the coordination of microgrids and distributed generations, which has incorporated the optimization for tie-line power, distributed consensus λ-iteration algorithm and reference tracking under the framework of multi-agent system. Using synchronous ADMM algorithm, the sub-optimization problems coupled with boundary constraints are transformed into decoupled sub-optimization problems. With the help of virtual leaders, both the scheduling of distributed generations and that of interconnected microgrids, are integrated. That is, it can infinitely approach to global optimization obtained by traditional centralized algorithm. On the other hand, it can avoid the sharing of participants’ private information and the need for a control center with a dedicated wide-area communication network. Finally, an actual study case with 5 microgrids verifies the effectiveness and robustness under various uncertainties of the proposed scheduling strategy.

The development of autonomous or semiautonomous surgical robots stands to improve the performance of existing teleoperated equipment but requires fine hand-eye calibration between the free-moving endoscopic camera and patient-side manipulator arms (PSMs). A novel method of solving this problem for the da Vinci robotic surgical system and kinematically similar systems is presented. First, a series of image-processing and optical-tracking operations are performed to compute the coordinate transformation between the endoscopic camera view frame and an optical-tracking marker permanently affixed to the camera body. Then, the kinematic properties of the PSM are exploited to compute the coordinate transformation between the kinematic base frame of the PSM and an optical marker permanently affixed thereto. Using these transformations, it is then possible to compute the spatial relationship between the PSM and the endoscopic camera using only one tracker snapshot of the two markers. The effectiveness of this calibration is demonstrated by successfully guiding the PSM end-effector to points of interest identified through the camera. Additional tests on a surgical task, namely, grasping a surgical needle, are also performed to validate the proposed method. The resulting visually guided robot positioning accuracy is better than the earlier hand-eye calibration results reported in the literature for the da Vinci system while supporting the intraoperative update of the calibration and requiring only devices that are already commonly used in the surgical environment. Note to Practitioners —The problem of hand-eye calibration for the da Vinci robotic surgical system and kinematically similar systems is addressed in this article. Existing approaches have insufficient accuracy to automate low-level surgical subtasks and often require external patterns or subjective human intervention, none of which are applicable to practical robotic minimally invasive surgery (RMIS) scenarios. This article breaks down the calibration procedure into systematic steps to reduce error accumulation. Most of the time-consuming steps are performed offline, allowing them to be retained between movements. Each time the passive joints of the manipulator or the endoscope move, all that needs to be done is to refresh the transformation between the fixed markers. This key idea enables intraoperative updates of the hand-eye calibration to be performed online without sacrificing precision. The calibration method presented here demonstrates that the achieved accuracy is sufficient for automating basic surgical manipulation tasks, such as grasping a suturing needle. The hand-eye calibration will be incorporated into a visually guided manipulation framework to perform high-precision autonomous surgical tasks.

Stability of inverter-dominated microgrids (MGs) faces many challenges such as inertia shortage, mutual interactions among converters and sudden external disturbances. To enhance the stability of MGs, a distributed non-linear stabiliser is designed in this study based on synergetic control theory. First, inverter interfaces are uniformly modelled as virtual synchronous generators, whose small-signal stability is then analysed with the state-space average method. Also, the objective of the following control strategy, i.e. the system unstable domain, is obtained. Second, macro-variables applicable to droop control are constructed based on the typical dynamic model and then the analytic expression of the controller output could be derived. When external disturbances occur, or droop coefficients with high gains are chosen, power system stability could be guaranteed by adding a non-linear stabiliser. Finally, taking a 9-node MG as an example, simulation verifies the feasibility of the proposed strategy in cases of small disturbances, large disturbances and mode transition.

To enhance the delay-dependent stability of interconnected microgrids, a novel adaptive control strategy is designed in this paper. Firstly, an adaptive robust control model is established to coordinate multi-MGs energy management. By regulating control parameters, Lyapunov stability without delay can be guaranteed. Secondly, stability evaluation methods considering uncertainty, such as mode perturbation and communication failure, are proposed to analyze delay-independent system. On this basis, to eliminate the adverse effects of delay caused by wide-area measurement, an active disturbance rejection stabilizer is designed here, which can be self-adjust adaptively via delayed time, and doesn’t require multiple iterations in the parameters regulation. Through Schur complement theorem, the analytic expression of feedback gains is obtained from linear matrix inequalities. Finally, with an IEEE 118-node test feeder as an example, the numerical simulation verifies the feasibility of the proposed stabilizer under the cases of long delays.

We report a highly efficient graphene-based modulator by using an edge plasmonic effect in this paper. The modulation efficiency of the proposed modulator can be as large as 1.58 dB/μm, which is several times larger than that of previous reported modulators. By enhancing the gap plasmon mode and the edge plasmonic effect in a well-designed diagonal waveguide, a wedge-to-wedge SPP mode is strongly confined in both horizontal and vertical directions in terms of a small mode area (Aef /A0

With the development of energy internet technology and smart power distribution & utilisation technology, multiparty interaction based on the complementarity of multi-energy demand has become an alternative solution to avoiding power shortage and improving comprehensive energy efficiency. The industrial integrated energy system with CCHP (combined cooling heating and power) as a generation source of heating and cooling energy is studied. Based on the traditional electrical demand response (DR) mechanism, the demand for electricity, heating and cooling is incorporated in the scope of generalised demand side resources. Considering the difference on price, demand and supply characteristics of multiple energy resources, the multi-energy-based DR scheme and the corresponding optimisation model are established to minimise dispatching expenses and improve the interaction between electricity companies, CCHP and industrial consumers. The numerical analysis shows that the proposed scheme could effectively engage CCHPs and consumers in multi-energy interaction, and the overall expenses can be significantly reduced.

Computational study of nanopillar Si/poly (3,4-ethylene dioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) heterojunction solar cell is performed by using finite element method to solve Poisson equation, drift-diffusion equations, and current continuity equations. The depletion width around the edge of the Si nanopillar is almost the same as that of planar junction, while the depletion width around the middle of the Si nanopillar is much wider than that of planar junction. As a result, besides the enhanced light absorption due to light trapping induced by nanopillar array as in previous studies, larger depletion region, which leads to higher electron-hole separation efficiency under light illumination, is another reason for short-circuit current increase of nanopillar solar cell. The reason for less open-circuit voltage of nanopillar solar cell is also clarified by explaining the reason for large dark current of the nanopillar solar cell compared to its planar structure counterpart as follows. The kink of the potential profile along the lines around the edge nanopillar leads to much sharper potential drop in the following depletion region, and results in greater hole density slope when the solar cells are forwarded biased. Since the Si/PEDOT:PSS behaves like a pn junction rather than a Schottky junction as clarified in the previous study and the PEDOT:PSS is much highly doped, nanopillar heterojunction has larger dark current than planar junction due to the larger hole diffusion current around Si nanopillar edge.

To improve the automation level of distributed generation, a hierarchical optimisation strategy is proposed in this study. The strategy consists of day-ahead dispatch and scheduling implementation by power control. The energy management framework about the multi-agent system is also designed. Given the collaborative gaming process between microgrid and distributed network, a day-ahead dispatch is used to minimise the general expenses. Moreover, considering security constraints, the secondary control strategy is proposed to realise the precise control of the active power, which is adaptive to voltage inconsistency. Besides, the consensus algorithm is utilised to trace the dispatch target of tie-line power by monitoring power deviation at the point of common coupling. Finally, a series of simulation verifies the effectiveness of the method proposed. The influence of communication delay is also discussed.

This paper provides an insight into the demand response (DR) optimization in distribution markets consisting of a retailer and multiple demand response aggregators (DRA), where a retailer determines DR incentives based on power consumption profile. Conventional DR optimization with global states and constraints is intractable to be implemented in a distributed framework, which restricts the application feasibility and the potential profit of DR. To handle these limitations, we design a multi-agent architecture for distributed demand response (DDR). An online data-mining method is developed to identify the characteristics of DR. A leader–follower structure decomposes the original problem into a leader problem with global variables and aggregators of sub-problems, where discrete singular consensus is designed to broadcast the leader’s strategy to followers in real-time. The distributed perturbation primal–dual sub-gradient (D-PPDS) algorithm is proposed to solve the DDR problem with global inequality constraints in a completely distributed fashion. The proposed DDR strategy is tested by an actual case. The simulation results demonstrate that the asynchronous D-PPDS algorithm can obtain the near-optimal solution of the problem with global inequality constraints, and is robust against delay or plug-and-play.

This paper presents an L-2L de-embedding method for characterizing the electromagnetic properties of through-silicon-vias (TSVs) in 3-D ICs. To the best of our knowledge, this is the first paper that discusses the use of de-embedding method for multiport TSVs. The L-2L de-embedding structure and the analysis algorithm are first introduced. Then, the techniques for meeting two crucial requirements in accurately applying the method on multiport TSVs are proposed. To meet these two requirements, the de-embedding structure is designed to enhance the symmetry and the shielding TSVs are used to decrease the mutual admittance. The simulation results show that with the appropriate design, the shielding TSVs are able to greatly reduce the mutual admittance with little impact on TSVs and RDLs. Finally, the performance of the designed structures with and without shielding TSVs is examined via both full-wave simulation and the measurements. With the full-wave simulation results of TSVs as reference, it turns out that the de-embedding accuracy is significantly improved with the shielding TSVs. Moreover, the de-embedding results based on the measurements show good agreements with those of the simulation ones.

This paper presents a series of scalable equivalent circuits using an analytical method describing the electromagnetic coupling in the lightly doped CMOS substrate and the isolation structures such as the implanted guard ring. Implemented in Grace Semiconductor Manufacturing Corporation (GSMC) generic 0.13μm RF CMOS technology, the measurement and full-wave simulation are carried out to verify the proposed models in a broad frequency band ranging from 100 MHz to 40 GHz. By analyzing these layout-dependant models in detail, some layout and substrate characteristics impacting on guard ring performance are concluded and the design flow with guidelines for the guard ring structures implementation in engineering practice for RF signal isolation are presented.

A low-profile broadband bandpass frequency selective surface (FSS) with two rapid band edges is proposed in this paper for 5G near-field applications. The overall structure consists of three metallic layers, separated by two thin substrates with a thickness of 0.07λ. In addition, some centro-symmetric miniaturized slots are introduced in the middle metallic layer to further improve its stability and reduce its physical dimensions. A corresponding equivalent circuit model (ECM) is also proposed to better analyze the principles of the proposed FSS. Finally, an FSS prototype working at the center frequency of 27.5 GHz with a relative -3 dB bandwidth of 20.5% is fabricated and measured. More than 25 dB shielding effectiveness can be obtained out of the passband for a bandwidth of 1.46 GHz in this experiment. Both 3-D full-wave simulations and ECM results are in good agreement with the experimental results, having a maximum deviation of only 2.257% in the transmission zeros and poles. These results demonstrate that the proposed FSS is a good candidate for 5G near-field EMI shielding.

An active absorber with nearly zero static power consumption is proposed based on nonvolatile floating-gate graphene structure. Such absorber has almost no static power consumption benefited from the nonvolatile design. In such design, the central graphene can capture the tunneled electrons under the positive applied voltage, but cannot release these electrons after removing the voltage since it is electrically isolated from the external electrodes. Therefore, no extra power is needed to sustain the conductivity of graphene. Moreover, our proposed absorber exhibits an extremely strong absorption capacity. Even taking the strict condition for the bandwidth where all the absorptivity inside the bandwidth are larger than 90% as criterion, the proposed absorber provides more than 60 GHz absorption bandwidth which is twice larger than previous results. Furthermore, the proposed absorber shows high tolerance against large incidence angle ( $60^\circ $ ), different polarizations and nonideal factors of graphene. The results may promote various future nonvolatile absorber designs.

Grid structures are rapidly evolving in view of contemporary energy policies which ensure the addition of more renewable sources to reduce the carbon footprint. Compared to a centralized approach, low voltage grids (decentralized and distributed) are promising approaches to integrating non-dispatchable renewable energy sources (RESs). Installing local micro level power generation sources such as fuel cells, microturbines, and energy storage systems are a recent trend which helps in the intermittent effects of RESs and makes microgrids less dependable on the main grid. Due to the increasing variety of distributed generation sources having diverse characteristics, power dispatch scheduling of distributed microgrids is becoming challenging. A dispatch scheduling solution from an operator's point of view is presented by the authors. The core objective of this study is to minimize the carbon emissions and the cost of each microgrid. Further, it is observed that sales and purchases from the main grid are reduced. Consequently, transmission losses are also decreased.

This paper considers the problem of distributed online economic dispatch (DOED) from sequential data using reinforcement learning. Learning operation behavior in high-dimension environments with constraints is a major challenge for the DOED of networked microgrids (MGs), where insufficient exploration disables agents to build complex policies. Therefore, this paper develops a hierarchical reinforcement learning (HRL) to handle the DOED problem, where radial basis function (RBF) approximation is incorporated to make policies in continuous space. Based on the hierarchical framework, the HRL algorithm increases the training efficiency and reduces computational cost. The online HRL achieves distributed selfadaption and better performance of real-time dispatch by a modest number of interacting variables. In addition, guided by domain knowledge, the HRL algorithm avoids onerous additional learning beyond feasible action space. In the case of an actual networked MGcluster in Qingdao with real operation data, simulation is conducted to verify that the proposed learning framework can reduce longterm operation costs and enhance operation stability. To explore the learning process, we also provide its convergence condition andanalyze the sensitivity of the learning parameters.

Monolayer MoS2 photodetectors are modeled and simulated by self-consistently solving diffusive transport equations in the presence of light illumination and carrier recombination with the 2-D Poisson equation. The simulated results indicate that very high photoresponsivity (PR) of $\sim 1000$ A/W observed in others’ experiments is due to strong electrostatic effect of pile up of optically generated holes, and efficient optical absorption. It is found that the value of PR is sensitive to gate bias voltage, and the photodetector performance can be improved by decreasing hole mobility if side effects of low hole mobility, such as high recombination rate, slow response speed, and more noise, are suppressed. High quality monolayer MoS2 with large electron mobility and less Shockley–Read–Hall recombination defects is desired for achieving high performance. The PR increases as the gate insulator thickness increases. The channel length needs to be carefully designed by considering the carrier recombination behavior in monolayer MoS2. The optimization method of monolayer MoS2 photodetectors proposed here is also applicable to other monolayer transition-metal dichalcogenide materials in general.

Because of environmental benefits, wind power is taking an increasing role meeting electricity demand. However, wind power tends to exhibit large uncertainty and is largely influenced by meteorological conditions. Apart from the variability, when multiple wind farms have geographical adjacency, their power generation also displays strong correlation. Thus, scenario generation considering the spatiotemporal relationships is a useful tool to model the stochastic process. In this work, we propose a wind power scenario generation framework based on the conditional improved Wasserstein generative adversarial network (WGAN). The framework includes a cluster analysis to establish the classification rule, a support vector classifier (SVC) to predict labels, a conditional scenario generation process based on improved WGAN, and finally a scenario reduction procedure. We demonstrate that the clustering analysis and SVC based labeling model can provide accurate classification results and the scenarios conditioned on input labels can not only follow the marginal distribution of each category but also capture the spatiotemporal relationships. We also illustrate that by adding a gradient penalty term to the discriminator’s loss function to enforce the Lipschitz constraint, the quality of scenarios is better than that of the existing method.

This letter presents a novel graphene-embedded optical ring modulator that significantly enhances the modulation efficiency and tunability. Due to the enhanced light-matter interaction of graphene-embedded design, the shift rate of the resonance peak has been improved to 1.08 nm per applied voltage, which is two orders of the magnitude higher than previous ring modulators. The narrow bandwidth of the resonant modulator has been ameliorated to 149 GHz. In addition, our proposed modulator exhibits the advantages of high extinction ratio (22.13 dB) and smaller power consumption. Furthermore, a good tolerance of temperature drift (27 K) has been demonstrated in the proposed modulator.

The power distribution network (PDN) impedance of 3-D-through silicon vias (TSVs) interposer layer is modeled by considering the metal-oxide-semiconductor (MOS) structure effects. The Lambert W function is proposed to simulate the change of depletion width with the bias voltage in the static field, and the high-frequency MOS capacitance is obtained while considering the charges at the semiconductor-insulator interface. Furthermore, based on the depletion width and the insulating dielectric layer assumption, the electrical model of power-ground TSVs pair is presented by combining the MOS capacitance with TSVs parasitic RLGC (resistance-inductance-capacitance-conductance). Finally, the PDN impedance characteristics of the 3-D-IC integrated system with multiple TSVs are performed by using the proposed multitransmission line and model reduction methods, and the importance of the capacitance is presented.

In this paper, we propose a novel double-shielded interposer design with two metal layers directly contacting to the silicon substrate surfaces for high-speed signal propagating along through silicon vias (TSVs). To enhance the shielding effects, shallow highly doped silicon is made on both sides of the silicon interposer forming ohmic contact between the metallization layer and silicon. The metallization layer is etched into meshed pattern to prevent delamination. Based on the imaging method, we derive the equivalent circuit model of the proposed double-shielded interposer, and the accuracy and efficiency of the equivalent circuit model is verified by full-wave method. The proposed design can concentrate the electromagnetic field around TSVs, so that it has a lower insertion loss than the conventional ground-signal (GS) structure without shielding. This is especially useful when the low-resistivity silicon is used for the interposer. Finally, some applied guidelines are proposed to strengthen the performance and simplify the silicon fabrication processes.

We propose a graphene-based modulator integrated into currently used communication fibers. The graphene is directly built into the core of the fiber to ensure the coupling efficiency. The fiber is deliberately side-polished to enhance the light-graphene interaction. The two-dimensional model analysis method and three-dimensional finite difference time domain method are used to rigorously disclose the light modulation mechanism under the anisotropic graphene modeling, which is merely conducted in previous studies. Based on such a structure, a phase modulator with an arm length of 127 μm is numerically demonstrated with enhanced modulation efficiency. A quasi-linear relation between the phase change and chemical potential of graphene is found theoretically for the first time, providing a large linear dynamic range to control the phase of optical modulation.

Graphene has shown promising perspectives in optical active components due to the large active-control of its permittivity-variation. This paper systematically reviews the recent developments of graphene-based optical modulators, including material property, different integration schemes, single-layer graphene-based modulator, multi-layer and few-layer graphene-based modulators, corresponding figure-of-merits, wavelength/temperature tolerance, and graphene-based fiber-optic modulator. The different treatments for graphene’s isotropic and anisotropic property were also discussed. The results showed graphene is an excellent material for enhancing silicon’s weak modulation capability after it is integrated into the silicon platform, and has great potentials for complementary metal oxide semiconductor (CMOS) compatible optical devices, showing significant influence on optical interconnects in future integrated optoelectronic circuits.

The investigation of few-layer graphene embedded in silicon waveguide (GESW) exhibits it has a superior performance than monolayer GESW where the effective mode index variation ( Δ n e f f ) at the given chemical potential change and the number of graphene layers N (N Δ n e f f of quadri-layer GESW can be as large as 0.047, based on which a Mach–Zehnder modulator has been proposed with the advantages of only 16.5 μm arm length, low energy consumption (8 fJ/bit), high extinction ration (31.8 dB) and small applied voltage (

The analytical model based on Poisson–Boltzmann equation in a cylindrical coordinate system is developed for simulating the electrical parameters of the three-dimensional Through Silicon Via (TSV) interconnection. Considering the effects of bias voltage, the accurate charge distribution and the high-frequency capacitance in the depletion layer of the semiconductor is obtained. Moreover, the resistance and inductance parameters of TSV are extracted by using the partial element equivalent circuit method. Finally, the full resistance–inductance–capacitance–conductance electrical model of TSV interconnection is presented first time with the semiconductor behaviour, and the transmission characteristics of signal-ground TSV structure are studied.

We analyze and optimize the performance of unconventional negative permeability (μ) metamaterial and demonstrate its ability to focus and restore the decaying Fourier harmonics (FH) in microwave regime operating frequencies. We show that multiple real μr' and imaginary μr'' values of μr at same or multiple operating frequencies for a resonant type of -μ metamaterial could not exhibit finest resolution at the region of interest (ROI), unless and until the distance of the source plane with respect to metamaterial and ROI could be re-optimized in accordance with μr' and μr'' of μr. Using the variable parameters to enhance the resolution limit of -μ metamaterial, we optimize the metamaterial's configuration for maximum propagation field absorption and regeneration of decaying FH at ROI. The optimization of the test bed that contains the source plane, -μ metamaterial, and ROI followed by the regeneration of the decaying FH from the source plane at the surface of the material, yielded a high image resolution at ROI.

The energy-momentum dispersion relation is a fundamental property of plasmonic systems. In this paper, we show that the method of dispersion engineering can be used for the design of ultra-compact graphene-based superscatterers. Based on the Bohr model, the dispersion relation of the equivalent planar waveguide is engineered to enhance the scattering cross section of a dielectric cylinder. Bohr conditions with different orders are fulfilled in multiple dispersion curves at the same resonant frequency. Thus the resonance peaks from the first and second order scattering terms are overlapped in the deepsubwavelength scale by delicately tuning the gap thickness between two graphene layers. Using this ultra-compact graphene-based superscatterer, the scattering cross section of the dielectric cylinder can be enhanced by five orders of magnitude., This paper has been accepted by IEEE Journal of Selected topics in Quantum Electronics

Slow light in planar photonic structures has attracted for some years an increasing interest due to amazing physical effects it allows or reinforces and to the degrees of freedom it raises for designing new optical functions. Controlling light group velocity is achieved through the use of periodical optical media obtained by nano-structuration of semiconductor wafers at the scale of light wavelength: the so-called photonic crystals. This article reviews present achievements realized in the field of slow light photonic bandgap structures, including the physical principles of slow light to the description of the most advanced integrated optical devices relying on it. Challenges and current hot topics related to slow light are discussed to highlight the balance between the advantages and drawbacks of using slow waves in integrated photonic structures. Then, future trends are described, which is focused on the use of slow wave slot waveguides for nonlinear optics and bio-photonic applications.

The effects of process-induced disorder location on planar photonic crystal waveguide properties are numerically investigated using three-dimensional finite difference time domain simulation by introducing random fluctuations of the hole radius, size, position, and shape of air-holes of two-dimensional planar photonic crystal slab. Results reveal that bandgap properties are extremely robust with respect to disorder. It is shown that the very first rows of holes play a major role in the amount of disorder-induced optical loss, and that keeping the first two rows of holes unchanged leads to a blue-shift of slow light waveguide properties.

An ultra-compact and low-loss transverse-electric (TE)-pass polarizer is proposed by utilizing a hybrid plasmonic ridge waveguide structure on a silicon-on-insulator platform. Since the transmission of a plasmonic polarizer is greatly influenced by the interaction between the metal and the optical field, there is a large insertion loss (IL) in the polarizer based on a hybrid plasmonic waveguide. Here, the electric field distribution and the periodic coupling between the fundamental transverse magnetic mode and plasmonic mode are taken into consideration to decrease the IL and shorten the length of the device. For a 4.2 μm-long polarizer, numerical simulations with the finite-differential-time-domain method show that it has a large extinction ratio (ER) of ∼29.5 dB with a low IL of 0.18 dB at the central wavelength 1550 nm. In addition, a more than 23 dB ER is achieved across a wide bandwidth of 100 nm.

This letter proposes a novel demodulation method for fiber-optic interferometer sensors. A fast square wave is added to the reference arm of the interferometer sensor in the form of phase modulation. Starting from this, we successfully developed a simple demodulation method that can greatly improve the conversion efficiency and overcome the unbalanced influences. Our experiment results show that a very small phase shift of about 6.3 × 10-5 rad can be detected, which proves high signal-to-noise ratio demodulated signal and low distortion in our demodulation method. The linearity between demodulated signal and test signal is shown to be over 99%.

Wideband slow light away from band edge in one-dimensional (1-D) structure is proposed and theoretically investigated for the first time. With carefully chosen structure parameters of the 1-D holey grating waveguide, an ideal chair shape band with unique inflection points of high group index beyond 1000 can be obtained. By chirping the structure according to the scaling law, wideband up to 31-nm slow light pulse propagation with a moderate group index of 14.6 is demonstrated by finite-difference time-domain simulation, and the relative pulse shape expansion is only 2.34%.

A novel type of semislow light photonic crystal waveguide obtained by shifting the boundaries of a W1 waveguide in the direction of light propagation is presented. The structure produces unusual "U-type" group index -frequency curves, which results in a nearly constant group index ng over large bandwidth. A versatile control of ng (11

Flat band slow light in symmetric line defect photonic crystal waveguides formed by adding dielectric pillars in the air holes nearest to the waveguide core is investigated. By adjusting the radii of the new dielectric pillars, a linear band in the photonic band structure appears which denotes low group velocity dispersion. High average group index of 74.4 with 2.3-nm bandwidth is demonstrated in an optimized waveguide by finite-difference time-domain simulation.

A hybrid plasmonic parallel transmission line scheme constructed by a spatial single mode with time-domain multiline waveguide is presented in this paper. The proposed configuration enables a nanometer light localization while retaining a long propagation distance (~74 μm) at optical communication wavelengths with no crosstalk between data channels. High extinction ratio between the nanoribs peak energies (~20 dB) has been achieved after optimization. Furthermore, the proposed optical parallel transmission line scheme shows the advantages of enabling an optical device with a large number of parallel transmission channels, as well as a good robustness with respect to the fabrication tolerances.

In this article, the fabrication process of annular photonic crystals on silicon-on-insulator wafers was addressed for the first time. A self-alignment procedure for nanofabrication using atomic layer deposition and sacrificial etching was established to place accurately nanosized dielectric rods in nanosized circular air holes. Avoiding the challenging electron-beam lithography alignment, this method achieves atomic level precision and shows high stability.