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Mass-deployable implementations for quantum communication require compact, reliable, and low-cost hardware solutions for photon generation, control and analysis. We present a fiber-pigtailed hybrid photonic circuit comprising nonlinear waveguides for photon-pair generation and a polymer interposer reaching 68 dB of pump suppression and photon separation based on a polarizing beam splitter with > 25 dB polarization extinction ratio. The optical stability of the hybrid assembly enhances the quality of the entanglement, and the efficient background suppression and photon routing further reduce accidental coincidences. We thus achieve a 96 - 8 + 3 % concurrence and a 96 - 5 + 2 % fidelity to a Bell state. The generated telecom-wavelength, time-bin entangled photon pairs are ideally suited for distributing Bell pairs over fiber networks with low dispersion. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of high-voltage flexible direct current (DC) transmission systems, more and more multi-port high-voltage DC systems have been successfully put into operation. Therefore, the number of connecting ports on the DC bus is gradually increasing, which necessitates higher requirements for clearing fault current. To better protect the DC power grid, this paper integrates a DC fault current limiter with a multi-port DC circuit breaker. This article proposes a modular cascaded multi-port hybrid DC circuit breaker topology. It also elaborates on the topology structure, working principle, and control program under three different fault conditions. It completes the theoretical derivation and analysis of the circuit breaker fault isolation process, as well as the parameter design of the core components. Finally, a model is established in PSCAD/EMTDC for simulation verification. The application performance of the circuit breaker in four-terminal DC systems is studied and analyzed, and the current-limiting effect of the multi-port DC circuit breaker proposed in this article is demonstrated. In addition, the disconnection performance and energy consumption of the arrester have been improved to a certain extent, which has good feasibility and economy. [ABSTRACT FROM AUTHOR]

In the field of fault isolation and clearance in flexible DC power grids, hybrid DC circuit breakers (HDCCB) have been widely used because of their advantages. However, their development is limited by high construction costs and inapplicability in some fault cases. In addition, adaptive reclosing capability is required for overhead DC lines with high fault probability. Therefore, this paper proposes a new type of multi-port hybrid DC circuit breaker (MP-HDCCB) with current limiting, breaking, and self-charging capabilities. The capacitor polarity reversal circuit is designed to reduce the influence of capacitor pre-charging on the normal operation of the system and to solve the problem of two consecutive line faults occurring in a short period of time. In addition, the circuit breaker can limit the current and break in the face of a single line fault, multiple line faults at the same time, and bus faults. It also has the ability of adaptive reclosing and normal operation of the line after a bus fault. Based on the proposed topology, a 500 kV four-terminal DC system is designed, and a model is established in PSCAD/EMTDC to verify the capabilities of the circuit breaker. Results show that the circuit breaker has adaptive reclosing capability and can realize fault current limiting and breaking under different fault conditions. [ABSTRACT FROM AUTHOR]

In this paper, a controllable hybrid plasmonic integrated circuit (CHPIC) composed of hybrid plasmonic waveguide (HPW)-based rhombic nano-antenna, polarization beam splitter, coupler, filter, and sensor has been designed and investigated for the first time. In order to control the power into a corresponding input port, a graphene-based 1 × 3 power splitter with switchable output has been exploited. The functionality of each device has been studied comprehensively based on the finite element method and the advantages over state-of-the-art have been compared. Moreover, the effect of connection of CHPIC to the photonic and plasmonic waveguides has been studied to exhibit the capability of variety excitation methods of the CHPIC. Furthermore, the performance of the proposed CHPIC connected to inter/intra wireless transmission links has been investigated. The wireless transmission link consists of two HPW-based nano-antennas as transmitter and receiver with the maximum gain and directivity of 10 dB and 10.2 dBi, respectively, at 193.5 THz. The suggested CHPIC can be used for applications such as optical wireless communication and inter/intra-chip optical interconnects. [ABSTRACT FROM AUTHOR]

Flexible direct current (DC) grids face a serious challenge in terms of rapidly isolating DC faults. A DC circuit breaker is an effective solution for DC fault isolation. To improve the fault-isolation and reclosing capability of flexible DC systems, a new high voltage direct current (HVDC) circuit breaker topology with adaptive reclosing capability is proposed in this paper. The topology of the circuit breaker is a T-shaped structure, which has the ability to break the current in both directions and effectively reduce the cost of components. Meanwhile, after the fault is cleared, the circuit breaker is controlled to inject a voltage signal into the line. Based on this, to prevent the circuit breaker reclosing in the event of a permanent fault from having an impact on the system, a method for fault identification based on Euclidean distance that uses the voltage signal to identify the fault properties is proposed. Finally, the performance of the circuit breaker is simulated and verified by PSCAD/EMTDC simulation software, and compared with the typical existing circuit breakers to verify the effectiveness of the circuit breaker and reclosing scheme. [ABSTRACT FROM AUTHOR]

Nowadays, traditional DC circuit breakers (DCCBs) are always expensive and lack current-limiting capabilities. Hence, this paper proposes a current limiting and low-cost hybrid DC circuit breaker (HCB). When a fault occurs, the paralleled inductors in the proposed HCB are converted to a series connection due to the cutoff of the converter module, effectively limiting the increase of fault current. Then the cascaded IGBTs undertake the transient interruption voltage. Energy dissipation circuits (EDCs) reduce the fault isolation time (FIT) by bypassing the current-limiting inductor during energy dissipation based on the metal oxide varistors (MOVs). Therefore, the proposed HCB can limit the rate of the fault current increase, reducing the FIT and cost. Finally, the feasibility of the proposed HCB is verified by a single-ended equivalent system and DC grid test systems built in PSCAD/EMTDC. In addition, the proposed HCB FIT is 33.7% quicker, its energy consumption is 87%, and its cost is lower than that of the traditional ABB HCB. [ABSTRACT FROM AUTHOR]

A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake (SP) insert no-insulation (NI) coil in a hybrid magnet during the charging and discharging processes. The coupled problem is resolved by means of the finite element method (FEM) for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system. The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet. Moreover, a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process, while a forward azimuthal current and a tensile hoop stress are observed during the discharging process. The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists. Therefore, it brings forth significant Joule heat, causing a temperature rise and a uniform distribution of this heat in the coil turns. Accordingly, a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil. It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil, while a discharging will not. The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications. [ABSTRACT FROM AUTHOR]

Four optical combinational circuits based on hybrid plasmonic waveguides utilizing squared-shaped nanoring resonators have been presented, designed, and studied standing on finite element method with COMSOL software package version 5.5. The optical combinational circuits half adder, half subtractor, full adder, and 4-bit binary to gray converter have been established in a layout with dimensions of 850 nm × 400 nm and 1750 nm × 400 nm for the 4-bit converter. The leading guide to building these optical circuits is the constructive and destructive interference founded on the phase shift angles between the input ports and the control port(s). The performance of the four optical combinational circuits has been evaluated based on the transmission value at each output port which has a threshold of 30%, contrast ratio, modulation depth, and insertion loss, with a system for an operating wavelength of 1310 nm. The transmission exceeds 100% in the full adder, in the output carry of the half adder, and in the most significant bit of the 4-bit binary to gray converter with a 202.6% each. Forty-six decibels is the value of the contrast ratio in the most significant bit of the converter and 99.99% as a modulation depth for the sum output of the full adder. [ABSTRACT FROM AUTHOR]

Hybrid perovskite solar cell technology has a distinct advantage over the conventional solar cell technologies due to its high predicted efficiency and low manufacturing cost. However, its commercialization is hindered by the unpredictability existing in its J-V characteristics leading to ambiguous efficiency estimation. Modeling the hysteresis in the J-V characteristics is a means of curtailing this ambiguity. It is established in literature that hysteresis models can be derived from the non-linear behavior of ferroelectric materials. Perovskite, which forms the light absorbing region of the solar cell is a ferroelectric material. In this paper, an equivalent circuit model for the hybrid perovskite solar cell is proposed in which the reasons for origin of hysteresis is characterized as varying capacitance to model hysteresis. A Landau–Khalatnikov subcircuit which portrays this variation is the principal addition to the conventional model to include hysteresis effect. The model parameters of the subcircuit are estimated from the inherent properties of perovskites. Hence, the proposed equivalent circuit model is completely physics based and it links the material property of perovskite to its equivalent circuit model parameters. [ABSTRACT FROM AUTHOR]

One of the urgent tasks in the design of hybrid integrated circuits (HICs) is the construction of adapter-attenuators of film absorbing elements that provide a wide range of attenuations with the given values of input and output resistances. Known versions of adapter-attenuators based on homogeneous and piecewise-homogeneous resistive films provide a resistance transformation ratio of not more than 3 and 10–12, respectively. The paper proposes promising topologies of adapter-attenuators for HICs with an almost optimal profile of the input and output contacts. It is shown that these topologies make it possible not only to obtain a wide range of transformation ratios (more than 100) but also to reduce the maximum values of the potential gradient and power density by a factor of 10 to 30. When calculating the rectangular topology, the apparatus of the theory of functions of a complex variable is used. The optimized topology of adapter-attenuators for HICs is modeled by the finite element method implemented in the Elcut software package. The calculated ratios and graphs that show the relationship between attenuation, the transformation ratio, gain in the potential gradient, and power density depending on the ratio of the dimensions of the film element and the specific resistances of the resistive films used are presented. The features of fitting adapter-attenuators are considered. The results obtained are important for the operation of the film element of adapter-attenuators for well logging in the pulsed mode. [ABSTRACT FROM AUTHOR]

This paper proposes a thyristor-based hybrid DC circuit breaker (HDCCB), which is composed of a fast mechanical circuit breaker and an LC resonant circuit with thyristor switches. The proposed HDCCB provides a zero-crossing point for fault current by injecting a resonant current in the reverse direction of the fault current. The proposed HDCCB has a low conduction loss in normal operation using a mechanical circuit breaker, and it offers the advantages of low cost, high reliability, and large capacity using thyristor switches instead of IGBT switches. It also has the design flexibility to adjust the magnitude of the injection current depending on the fault current level. A bidirectional HDCCB is also proposed by adding several components to the developed unidirectional HDCCB, which can offer compact system size and low system cost. Design considerations of the proposed structure are discussed. The validity of the proposed HDCCB is verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

We present a one-step method to realize a multi-qubit controlled phase gate of multiple nitrogen-vacancy-center ensembles (NV ensembles). This multi-qubit phase gate is based on cross-Kerr nonlinearities, which are enabled by a superconducting flux qutrit dispersively coupled to multiple NV ensembles. Since the flux qutrit is not populated during the operation, the effect of qutrit decoherence is greatly suppressed. Moreover, the gate operation time is independent of the number of NV ensembles. Numerical simulations show that high-fidelity construction of a four-qubit controlled phase gate with four NV ensembles is feasible with present hybrid circuit QED technology. [ABSTRACT FROM AUTHOR]

Servo circuit of quartz flexible accelerometer is an important signal processing unit in inertial measurement system. This paper introduced the working principle of the quartz flexible accelerometer and the composition of the servo circuit. Taking the output saturation of a quartz flexible accelerometer during the test process of inertial measurement unit as an example, according to the failure analysis process of hybrid integrated accelerometer servo circuit and the fault tree analysis based on accelerometer servo circuit fault diagnosis expert system, the fault location and failure analysis of the failed circuit are carried out, and the failure mechanism and causes are studied and analyzed. The analysis results show that the failure circuit is caused by electrical damage to the differential capacitance detector in the differential capacitance–voltage converter. In view of this problem, the prevention and improvement measures are put forward to reduce the frequency of the failure mode. Above analysis and research are of guiding significance to improve the fault analysis technology and the use reliability of servo circuit of hybrid integrated quartz flexible accelerometer. [ABSTRACT FROM AUTHOR]

For the development of the market of modern microelectronics, methods are required that allow continuously increasing the productivity and energy efficiency of semiconductor products and, at the same time, reducing the required minimum area of the crystal while maintaining its functionality. Therefore, the integration of nonvolatile elements (memristors) and CMOS technologies, as well as the creation of methods for synthesizing digital circuits with smmristor functional units—memristor logic (MeMOS logic)—are urgent problems. The paper proposes a block method for the synthesis of hybrid MeMOS circuits, using minterm maps, which makes it possible to simultaneously synthesize a MeMOS circuit and optimize it. Examples of the synthesis of combinational (Exclusive OR) and sequential (RS-trigger) schemes. The existing and new variants of solutions to problems of the synthesis of combinational and sequential integrated circuits with memristors are considered. It is shown that the average power dissipated RS-trigger is 7.7 μW for the standard logic and 2.2 μW for the memristor logic. The power consumption of the XOR circuit is 13 μW for the standard logic and 9.2 μW for the memristor logic. [ABSTRACT FROM AUTHOR]

Due to the rapid development of DC transmission, research on DC side fault protection has also made significant progress. The bipolar short-circuit fault is one of the most severe types of DC side faults. It can cause a current surge, which affects the safe operation of a system. Therefore, this paper proposes a new type of hybrid DC circuit breaker (DCCB) to realize the rapid suppression of bipolar short-circuit current. The new DCCB consists of three parts: a nominal current branch (NCB), an energy absorption branch (EAB), and a freewheeling branch (FB). Different control strategies can be adopted to achieve line protection functions for different types of faults. For transient faults, the absorption and suppression of the fault current are achieved mainly through the EAB and FB. The DCCB ensures that the amplitude of the current delivered by the DC line is maintained in a safe operating area of the transmission line. The EAB is disconnected after a short-term of operation for permanent faults to achieve complete isolation between the converter side and the fault side. The parameter design of the DCCB is carried out to provide a reference for the practical application of this research. Finally, the effectiveness of the proposed DCCB protection strategy is verified by simulations, and the function of the DCCB is further verified by experiments. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) has the advantages of flexibility, safety, and high reliability. Thus, it is widely used in portable electronic equipment, electric vehicles (EV), medical equipment, and other fields. The resonance compensation method of wireless charging directly affects the gain characteristics of the output current and voltage. As a result, this is one of the main research focuses of wireless power transmission technology. A new hybrid compensation topology circuit is proposed in this paper, which is based on the EV constant-current (CC) and constant-voltage (CV) charging mode. In this hybrid topology circuit, an equivalent loosely coupled transformer T model is established for the primary and secondary coils. Through an analysis of the circuit principle, it is concluded that the wireless power transmission circuit can realize CC and CV outputs under a dynamic load change. The output power efficiency characteristics of the serial/parallel (S/P) compensation and serial/serial (S/S) compensation circuits are analyzed. In addition, the mutual inductance parameters are optimized by an efficiency power product method to achieve the overall optimal parameter design in terms of the circuit output power and efficiency. A simulation model and an experimental prototype of the wireless power transmission circuit are established. The design process of the circuit parameters under a given target current and voltage is also presented. The simulation verifies the correctness of the constant current and constant voltage output of the S/P–S/S hybrid compensation circuit. The experimental platform verifies the CC output under the S/P compensation topology, and the CV output under the serial/serial (S/S) compensation topology. [ABSTRACT FROM AUTHOR]

The emerging interconnections of renewable energy sources that generate DC power have resulted in demands on DC grid systems. In this situation, a low-voltage DC (LVDC) grid system could be a solution for these DC power sources. For the reliable operation of a LVDC grid, DC faults are an issue and DC circuit breakers (DC CBs) are appropriate devices to clear fault current. However, there are some difficulties in terms of breaking DC faults such as the absence of zero crossing of the current and voltage, and the high di/dt of the fault current. This paper proposes a hybrid circuit breaker (HCB) with a new structure for a LVDC grid system. The main switch consists of a vacuum interrupter (VI) and a permanent magnetic actuator (PMA). Some improvements are proposed to enhance the performance of the PMA. A bi-directional commutation loop consisting of a minimum number of power electronic devices is suggested. To absorb fault energy, a capacitor and a diode loop are applied. The principle of the proposed HCB and the design methods for all of the components are analyzed. Through a simulation model, the designed components are selected and verified. Experimental results with a realized prototype (750 V/300A) verify the design method and its performance. [ABSTRACT FROM AUTHOR]