Input Phase Research Articles

Generation of photons with all-optically-reconfigurable entanglement in integrated nonlinear waveguides

We predict that all-optically-reconfigurable generation of photon pairs with tailored spatial entanglement can be realized via spontaneous parametric down conversion in integrated nonlinear coupled waveguides. The required elements of the output quantum wave function are directly mapped from the amplitudes and phases of the classical laser pump inputs in each waveguide. This is achieved through special nonuniform domain poling, which locally inverts the sign of quadratic nonlinear susceptibility and accordingly shapes the interference of biphoton quantum states generated along the waveguides. We demonstrate a device configuration for the generation of any linear combination of two-photon Bell states.

Modeling and Controller Design for a SEries-Connected Output Universal Link Converter

This paper conducts modeling and controller design for a SEries-connected Output Universal Link (SEOUL) converter. The SEOUL converter was proposed to interface multiple distributed power sources to the grid with a reduced amount of reactive components. It employs a high-frequency (HF) transformer instead of a bulky line-frequency transformer like solid-state transformers (SSTs). In addition, it does not use a large dc-link capacitor at the input side and reduces the size of the input filter. This is inherently possible due to its original operating characteristic. The input phase current is not actively controlled but synthesized indirectly by HF power transfer between input and output sides of the SEOUL converter. Therefore, it is important to properly control the HF power transfer part, on which this paper focuses. An analytic model is developed, and a control strategy is proposed based on the model with a decoupling control method. The developed model and the proposed control method were verified by experiments.

Phase-diversity phase-sensitive amplification in fiber loop with polarization beam splitter

In this paper, we propose a parametric amplification scheme based on phase-sensitive amplification in an optical fiber. The proposed system consists of a nonlinear fiber and a dispersive medium in a loop configuration with a polarization beam splitter, where phase-sensitive amplification occurs bi-directionally. The dispersive medium shifts the relative phase between signal and pump lights, due to which the amplified signal light is always obtained regardless of the signal input phase, i.e., a phase-diversity operation is achieved, while the output phase is digitized as in conventional phase-sensitive amplifiers.

Design and implementation of the monitoring and control systems for distribution transformer by using GSM network

Abstract This paper designs and implements the monitoring and control systems for tap changer of the distribution transformers by using GSM (global system for mobile) network. The proposed method comprises an embedded system which collects and processes the transformer parameters such as temperature, humidity, silicone gel color, Buchholz relay status, the status of input and output phases, the current flow in each phase and power of each phase. If the parameters exceed the permitted level, the system sends all parameters using the GSM modem through GSM network to the control center, and the center receives and processes them by the GSM modem, and then they are displayed on computer. Furthermore, some commands are sent from the center to change the tap changer position, denoting the transformer position and making report on the transformer parameters. Some advantages of this system can be denoted as extending the lifetime of the transformer, consumers, wires and facilities, no need to the operator, simplifying the troubleshooting in distribution network, balancing the loads and providing customers with proper service.

A Biomedical Search Support System for Improving the Data Search Accuracy

Medical domain is a huge scientific domain where a large amount of data is available for analysis and discovery. In this proposed work a search improvement technique is suggested which provides guidelines for finding appropriate data during medicine search. That is because the basic search systems contains three major modules first query interface, second for search methodology and finally search ranking. User provide input to the search interface than the search system find the data from database according to the user query, finally results are ranked according to the relevancy of the user query. The proposed improvement is implemented on the query input phase for improving the user query for finding the more accurate and nearer medicines from the database.

60-GHz Polarization-Adjustable Antenna Arrays

This paper proposes $2 \times 2$ and $4 \times 4$ polarization-adjustable millimeter-wave antenna arrays. The antennas were designed to function at 60 GHz and are planar and vialess. The proposed antenna designs contain two input ports; if the input phases and magnitudes of the two input ports can be controlled, enabling the proposed antenna to generate six types of polarization: right-handed circular polarization, left-handed circular polarization, and linear polarization along the ${\rm \varphi } = 0^\circ $ , ${\rm \varphi } = 45^\circ $ , ${\rm \varphi } = 90^\circ $ , and ${\rm \varphi } = 135^\circ $ axes. The achieved antenna gain of the $2 \times 2$ polarization diversity array was approximately 12 dBi, whereas that of the $4 \times 4$ array was 16 dBi. Prototypes of both the $2 \times 2$ and $4 \times 4$ arrays were fabricated and tested. The operating mechanism and design steps are described in detail in this paper.

Near‐zero dead zone phase frequency detector with wide input frequency difference

An all-digital phase frequency detector design capable of accepting an infinite range of input frequency differences and [0 2π] radians input phase difference is presented. The proposed phase frequency detector design minimises the dead zone, supresses unwanted output glitches, achieves a high maximum operating frequency, can drive high-capacitive loads and avoids differential outputs. The proposed phase frequency detector takes advantage of a fast reset operation from modified tristate inverters acting as a D flip-flop. Simulation results indicate that the design can detect input phase differences as small as 750 fs apart for all process corners at input operating frequencies of 38 kHz–2.5 GHz in 1.2 V, 90 nm CMOS technology.

Dynamic control of light beams in second harmonic generation.

In this Letter, we report the dynamic control of the spatial shape of the second harmonic (SH) beam generated in a nonlinear crystal, by controlling the phase of the input fundamental beam before entering the crystal. This method enables 2D beam shaping and does not require any special fabrication beforehand. We have shown in simulation and experiment that this is possible for both short and long crystals: for short crystals, we assume the transverse phase of the SH beam is doubled relative to the input phase of the fundamental beam; for longer crystals, genetic algorithms were used in order to solve the inverse phase problem, which generally does not have an analytical solution. The method we present enables us to dynamically shape a beam in a nonlinear process, using standard crystals and optical equipment, and without the need to use any optical element after the nonlinear crystal.

HCN channels enhance spike phase coherence and regulate the phase of spikes and LFPs in the theta-frequency range

What are the implications for the existence of subthreshold ion channels, their localization profiles, and plasticity on local field potentials (LFPs)? Here, we assessed the role of hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels in altering hippocampal theta-frequency LFPs and the associated spike phase. We presented spatiotemporally randomized, balanced theta-modulated excitatory and inhibitory inputs to somatically aligned, morphologically realistic pyramidal neuron models spread across a cylindrical neuropil. We computed LFPs from seven electrode sites and found that the insertion of an experimentally constrained HCN-conductance gradient into these neurons introduced a location-dependent lead in the LFP phase without significantly altering its amplitude. Further, neurons fired action potentials at a specific theta phase of the LFP, and the insertion of HCN channels introduced large lags in this spike phase and a striking enhancement in neuronal spike-phase coherence. Importantly, graded changes in either HCN conductance or its half-maximal activation voltage resulted in graded changes in LFP and spike phases. Our conclusions on the impact of HCN channels on LFPs and spike phase were invariant to changes in neuropil size, to morphological heterogeneity, to excitatory or inhibitory synaptic scaling, and to shifts in the onset phase of inhibitory inputs. Finally, we selectively abolished the inductive lead in the impedance phase introduced by HCN channels without altering neuronal excitability and found that this inductive phase lead contributed significantly to changes in LFP and spike phase. Our results uncover specific roles for HCN channels and their plasticity in phase-coding schemas and in the formation and dynamic reconfiguration of neuronal cell assemblies.

Pattern recognition with magnonic holographic memory device

In this work, we present experimental data demonstrating the possibility of using magnonic holographic devices for pattern recognition. The prototype eight-terminal device consists of a magnetic matrix with micro-antennas placed on the periphery of the matrix to excite and detect spin waves. The principle of operation is based on the effect of spin wave interference, which is similar to the operation of optical holographic devices. Input information is encoded in the phases of the spin waves generated on the edges of the magnonic matrix, while the output corresponds to the amplitude of the inductive voltage produced by the interfering spin waves on the other side of the matrix. The level of the output voltage depends on the combination of the input phases as well as on the internal structure of the magnonic matrix. Experimental data collected for several magnonic matrixes show the unique output signatures in which maxima and minima correspond to specific input phase patterns. Potentially, magnonic holographic devices may provide a higher storage density compare to optical counterparts due to a shorter wavelength and compatibility with conventional electronic devices. The challenges and shortcoming of the magnonic holographic devices are also discussed.

Soliton Formation in Whispering-Gallery-Mode Resonators via Input Phase Modulation

We propose a systematic method for soliton formation in whispering-gallery-mode (WGM) resonators through input phase modulation. Our numerical simulations of a variant of the Lugiato–Lefever equation (LLE) suggest that modulating the input phase at a frequency equal to the resonator free spectral range and at modest modulation depths provides a deterministic route toward soliton formation in WGM resonators without undergoing a chaotic phase. We show that the generated solitonic state is sustained when the modulation is turned off adiabatically. Our results support parametric seeding as a powerful means of control, in addition to input pump power and pump-resonance detuning, over frequency comb generation in WGM resonators. Our findings also help pave the way toward ultrashort pulse formation on a chip.

A 2.5-Gb/s DLL-Based Burst-Mode Clock and Data Recovery Circuit With <inline-formula> <tex-math notation="LaTeX">$4\times$ </tex-math></inline-formula> Oversampling

In this brief, a delay-locked loop (DLL)-based burst-mode clock and data recovery (BMCDR) circuit using a $4\times$ oversampling technique is realized for passive optical network. With the help of DLL to track the input phase, the proposed circuit can recover the burst-mode data in a short acquisition time and achieve large jitter tolerance. In addition, a 2.5-GHz four-phase clock generator is embedded in the chip. Implemented with a 0.18- $\mu{\rm m}$ CMOS technology, experiment shows that the acquisition time can be accomplished in the time of 31 bits. Incoming 2.5-Gb/s input data of $2^{31}{-}1$ pseudorandom binary sequence, the retimed data has a root-mean-square jitter of 8.557 ps and a peak-to-peak jitter of 32.0 ps, and the measured bit error rate is less than $10^{-10}$ . The area of the whole chip is 1.4 $\,\times\,$ 1.4 ${\rm mm}^{2}$ , where the BMCDR circuit core occupies 0.81 $\,\times\,$ 0.325 ${\rm mm}^{2}$ . The total power consumption is 130 mW from a 1.8 V supply voltage.

The 40‐Hz auditory steady‐state response: a selective biomarker for cortical NMDA function

When subjected to a phasic input, sensory cortical neurons display a remarkable ability to entrain faithfully to the driving stimuli. The entrainment to rhythmic sound stimuli is often referred to as the auditory steady-state response (ASSR) and can be captured using noninvasive techniques, such as scalp-recorded electroencephalography (EEG). An ASSR to a driving frequency of approximately 40 Hz is particularly interesting in that it shows, in relative terms, maximal power, synchrony, and synaptic activity. Moreover, the 40-Hz ASSR has been consistently found to be abnormal in schizophrenia patients across multiple studies. The nature of the reported abnormality has been less consistent; while most studies report a deficit in entrainment, several studies have reported increased signal power, particularly when there are concurrent positive symptoms, such as auditory hallucinations. However, the neuropharmacological basis for the 40-Hz ASSR, as well as its dysfunction in schizophrenia, has been unclear until recently. On the basis of several recent reports, it is argued that the 40-Hz ASSR represents a specific marker for cortical NMDA transmission. If confirmed, the 40-Hz ASSR may be a simple and easy-to-access pharmacodynamic biomarker for testing the integrity of cortical NMDA neurotransmission that is robustly translational across species.

Cell Type-Specific Control of Spike Timing by Gamma-Band Oscillatory Inhibition.

Many lines of theoretical and experimental investigation have suggested that gamma oscillations provide a temporal framework for cortical information processing, acting to either synchronize neuronal firing, restrict neuron's relative spike times, and/or provide a global reference signal to which neurons encode input strength. Each theory has been disputed and some believe that gamma is an epiphenomenon. We investigated the biophysical plausibility of these theories by performing in vitro whole-cell recordings from 6 cortical neuron subtypes and examining how gamma-band and slow fluctuations in injected input affect precision and phase of spike timing. We find that gamma is at least partially able to restrict the spike timing in all subtypes tested, but to varying degrees. Gamma exerts more precise control of spike timing in pyramidal neurons involved in cortico-cortical versus cortico-subcortical communication and in inhibitory neurons that target somatic versus dendritic compartments. We also find that relatively few subtypes are capable of phase-based information coding. Using simple neuron models and dynamic clamp, we determine which intrinsic differences lead to these variations in responsiveness and discuss both the flexibility and confounds of gamma-based spike-timing systems.

Polarization or phase insensitive fiber parametric amplifier with clamped output phase.

This paper proposes a low polarization- or phase-dependent fiber parametric amplifier system with a clamped output phase, which consists of an orthogonally pumped nonlinear fiber and a fiber loop with a polarization beam splitter. Numerical calculations show that the proposed system exhibits a constant output phase, low insensitive to the signal input phase or polarization state.

RF phase stability in the 100-MeV proton linac operation

The 100-MeV proton linac of the Korea multi-purpose accelerator complex (KOMAC) has been operated to provide a proton beam to users. The 100-MeV linac consists of a 3-MeV radio-frequency quadrupole accelerator (RFQ), four 20-MeV drift-tube linac (DTL) tanks, two medium-energy beam-transmitter (MEBT) tanks, and seven 100-MeV DTL tanks. The requirements of the field stability are within ±1% in RF amplitude and ±1 degree in RF phase. The RF phase stability is influenced by a RF reference line, RF transmission lines, and a RF control system. The RF reference signal is chosen to be a 300-MHz local oscillator (LO) signal, and a rigid copper coaxial line with temperature control was installed for an RF reference distribution. A phase stability of ±0.1 degrees was measured under a temperature change of ±0.1 °C. A digital feedback control system with a field-programmable gate-array (FPGA) module was adopted for a high RF stability. The RF phase was maintained within ±0.1 degrees with a dummy cavity and was within ±0.3 degrees at RFQ operation. In the case of the 20-MeV DTL tanks, one klystron drives 4 tanks, and the input phases of 4 tanks were designed to be in phase. The input phases of 4 tanks were fixed within ±1 degree by adjusting a phase shifter in each waveguide.

Defect induced wave-packet dynamics in linear one-dimensional photonic lattices

We study numerically light beam propagation across uniform, linear, one-dimensional photonic lattice possessing one nonlinear defect. Depending on the strength of nonlinear defect, input beam position and phase shift, different dynamical regimes have been identified. We distinguish input parameters set for which a regime of light propagation blockade by the nonlinear defect appears. Obtained results may be useful for all-optical control of transmission of waves in interferometry.

A phase-image watermarking scheme in gyrator domain using devil's vortex Fresnel lens as a phase mask

We propose a watermarking scheme for phase images, based on the use of devil’s vortex Fresnel lens (DVFL) as a phase mask. The DVFL provides much-desired parameter-rich phase masks which contribute to the enhanced security of the scheme in addition to overcoming the problem of axis alignment in the optical setup. The scheme uses gyrator transform (GT) in the input and the frequency domains to encrypt the input phase image before combining it with a host image. The scheme is validated for its efficacy, and analyzed for its sensitivity to various encryption parameters. Finally, it is examined for its robustness against occlusion and noise attacks.

Optimized designing of a patch phased array with a MoM-solver

Purpose – The purpose of this paper is to present an optimization process for the design of a 2×2 patch antenna phased array with application for an UHF RFID system. Design/methodology/approach – The optimization process is based on a method of moment (MoM)-solver, which was individually made to create such patch antenna phased arrays and simulate the radiated field pattern. In combination with this MoM-solver, a GUI, which gives the opportunity to change every physical antenna factor and create the antenna structure within a few minutes is presented. Furthermore the golden section search method is used to produce an even better solution in a more efficient way compared to the first attempt. After the simulation, different types of presentation of results can be chosen for a fast and easy optimization. Findings – The design process is discussed while the authors try to optimize the distance between the elements and the difference of input phase for each patch element. The final goal is to create an antenna with maximum directivity and coverage of field pattern. Practical implications – A physical implementation of an optimized patch antenna phased array and the results of measurement are presented in the end. Originality/value – An optimization process for the design of a 2×2 patch antenna phased array with application for an UHF RFID system is presented. Furthermore the golden section search method is combined with the design process to increase the accuracy of the solution and decrease the time effort.

A Novel Space Vector Technique for the Direct Three-level Matrix Converter

This study proposes a novel Direct Torque Control (DTC) method for the Direct Three level Matrix Converter (DTMC), which uses both the input phase voltage vectors (short vectors) and the input line voltage vectors (long vectors). The problem of voltage imbalance at the input filter capacitance due to the use of the short vectors is addressed with an additional voltage hysteresis comparator. With the errors of torque, flux, sin Ψ and the neutral point voltage, an Optimum Switching Table (OST) is designed for the DTMC. The OST generates the necessary switching signals for the DTC of the DTMC. The DTMC topology with the modified ISVM technique reduces the THD at the output. The proposed DTMC Indirect Space Vector pulse width Modulation (ISVM) technique uses the idea of multilevel inverter SVM technique along with the proposed neutral current balancing strategy for generating the firing pulses. The switching loss model for the DTMC is developed and the performance of the DTMC is compared with that of the Conventional Matrix Converter (CMC). The performance of the proposed DTC technique for the DTMC is evaluated through simulation to explain the reduced torque ripple characteristics. To validate the proposed DTMC ISVM technique, a 3 kVA direct multilevel matrix converter prototype was developed.