Single Output Port Research Articles

Generalized Mach Zehnder Interferometers Integrated on Si3N4 Waveguide Platform

We demonstrate 3 × 3 and 4 × 4 Generalized Mach Zehnder Interferometers (GMZI) integrated on the Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> waveguide platform and present their experimental performance as switching and variable power splitting modules. The GMZI structures have been theoretically modelled by means of a transfer matrix model, evaluating also the GMZI spectral response in the case of fabrication errors that may lead to variations in GMZI arm lengths, MMI phase shifts and MMI splitting ratios. Both 3 × 3 and 4 × 4 GMZI structures were fabricated as integrated Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -based circuits and were experimentally characterized with the experimental results being in close agreement with the theoretical predictions. They both reveal a resonant spectral behavior with an FSR of 1.9 nm and low average insertion losses per port that were measured to be 1 ± 0.2 and 2.4 ± 0.4 dB. The two GMZI structures were utilized as 1:3 and 1:4 switching elements, respectively, with average crosstalk levels being always greater than 10 dB for all possible input-output port combinations. Finally, their credentials to serve within linear optical circuit implementations were evaluated through their experimental characterization in variable power splitting applications, showing that the power level at a single output port can take any value between 0 and 100% of the input signal.

Self-configuring programmable silicon photonic filter for integrated microwave photonic processors

Reconfigurable photonic filters show great promise as a potential solution to meet the evolving needs of future microwave communication systems. By integrating high-performance filters into programmable microwave photonic processors, they can provide significant benefits for signal processing applications. The development of an algorithm that can automatically characterize and reconfigure the filter using a single optical input and output port is essential for this purpose. This paper presents an optimization technique for a fully tunable ring-assisted Mach–Zehnder interferometer filter. The proposed filter design eliminates the need for monitoring components and employs a novel algorithm that operates independently in each ring by switching between the two arms of the filter. In addition, the filter can be configured to implement different filter architectures, allowing for flexible filtering requirements. Measurements were performed using the device as an interleaver, implementing different types of infinite impulse response filters in the optical and radio frequency domains. Side-coupled integrated spaced sequence of resonator filters were also implemented by reconfiguring the same device. These results demonstrate the exceptional reconfigurability of the filter design proposed herein in terms of bandwidth and central frequency.

Double-port homodyne detection in a squeezed-state interferometry with a binary-outcome data processing

Performing homodyne detection at a single output port of a squeezed-state light interferometer and then separating the measurement quadrature into two intervals can realize super-resolving and super-sensitive phase measurements, which is equivalent to a binary-outcome measurement. Obviously, the single-port homodyne detection may lose almost part of the phase information, reducing the estimation precision. Here, we propose a data-processing technique over the double-port homodyne detection, where the two-dimensional measurement quadrature (p 1, p 2) has been divided into two regions. With such a binary-outcome measurement, we estimate the phase shift accumulated in the interferometer by inverting the output signal. By analyzing the full width at half maximum of the signal and the phase sensitivity, we show that both the resolution and the achievable sensitivity are better than that of the previous binary-outcome scheme.

Analysis of End-Effect Torque and Multi-Objective Optimization for Multi-Port Spatial Permanent Magnet Synchronous Motor

Multi-port spatial permanent magnet synchronous motor (MSPMSM) combines the advantages of disk motor and permanent magnet (PM) planetary gear drive, which solves the problem of single output port on traditional PM synchronous motor (PMSM) and realizes multi-port outputs and direct drive. Due to the special structure of disk stator, the planetary gear rotors are affected by end-effect torque in rotation process. The end-effect torque will not only cause torque ripple but also cause vibration and noise. Aiming at the problem of end-effect torque, the generation mechanism of end-effect torque is analyzed. In order to analyze air-gap magnetic field distribution accurately, the arc slotless subdomain (SD) model of planetary gear rotor and disk stator is established in polar coordinate system. The end-effect torque is derived by the Maxwell stress tensor method. Based on Box–Behnken design (BBD) method, a response surface model (RSM) is constructed to reduce end-effect torque amplitude and increase electromagnetic torque. The influences of structural parameters on end-effect torque amplitude are analyzed, and a set of optimal structural parameters are obtained. The end-effect torque and electromagnetic torque of the optimized MSPMSM are analyzed by finite-element analysis method (FEM), and the effectiveness of multi-objective optimization design method is verified. These research results have a good effect on improving the output performance of MSPMSM.

High performance of dual input H-bridge DC-DC converter in solar application

Three-port power converter (TPC) is key element in solar photo-voltaic (PV)-battery based power conversion applications. In this paper, dual input bridge converter (DIBC) is considered, which is a TPC with high-frequency transformer isolation between power source and load. It has dual inputs for connecting two energy sources (PV module and battery) and single output port. At first, this paper describes design steps to decuple two important controllers, namely input voltage controller (IVC) and output voltage controller (OVC) for load. Here, the switching signals for four power semiconductor switches of the DIBC are produced by joint actions of above said control loops. The performance of traditional system is found satisfactory under maximum power point tracking (MPPT) operation. But the conventional system fails to work during fully charging condition of battery during MPPT mode due to power imbalance and it can also overcharge battery. In the situation, load power tracking (LPT) operation for DIBC is developed and proposed in this paper to keep power balance. Thus, the overcharging of battery is prevented by LPT operation and thus, degradation of battery is avoided i.e. its life-time can be improved. The controllability of DIBC under MPPT and LPT modes is verified through MATLAB-SIMULINK software and hardware testing prototype. The obtained results of both studies affirm high performances of overall system during wide operating conditions.

Efficient tunable plasmonic mode converters infiltrated with nematic liquid crystal layers

This paper presents two efficient tunable plasmonic mode converters in the infrared regime. The proposed configurations consist of silver layer with etched rectangular holes as metal insulator metal waveguides with central cavities. The holes are infiltrated by nematic liquid crystal (NLC) material to increase the transmission through the suggested designs. Additionally, the NLC is used to have tunable operation where the modes at the output port can be controlled. The simulations are carried out using full vectorial finite element method. The first design has a single output port which converts the TM mode into the TEM mode with high transmission conversion efficiency of 70%. Further, the second structure allows the generation of the two plasmonic modes simultaneously in two output waveguides. During the biased state, the s- mode transmission conversion efficiency reaches 50% while the transmission of a- mode at the unbiased state is equal to 49%. It is expected that the proposed tunable mode converters will play an important role in the development of the plasmonic-photonic circuits.

Single-Port Homodyne Detection in a Squeezed-State Interferometry with Optimal Data Processing

Performing homodyne detection at a single output port of a squeezed-state light interferometer and then separating the measurement quadrature into several bins can realize superresolving and supersensitive phase measurements. However, the phase resolution and the achievable phase sensitivity depend on the bin size that is adopted in the data processing. By maximizing classical Fisher information, we analytically derive an optimal value of the bin size and the associated best sensitivity for the case of three bins, which can be regarded as a three-outcome measurement. Our results indicate that both the resolution and the achievable sensitivity are better than that of the previous binary–outcome case. Finally, we present an approximate maximum Likelihood estimator to asymptotically saturate the ultimate lower bound of the phase sensitivity.

A Multi-Bandgap Periodic Structure Device Acting as Multiplexer or Demultiplexer of Electromagnetic Signals

In this work, a device capable of acting as a multiplexer (MUX) and demultiplexer (DEMUX) for electromagnetic waves in gigahertz range is designed and modeled numerically. The device is based on optimized dielectric periodic structures. It can combine signals of different central frequencies injected at its input ports to a single output port, thus acting as a MUX. Reciprocally, the device can separate mixed signals of different frequencies to specific output ports, acting as a DEMUX. To this aim, specific imperfections are introduced into the periodic structure. The design and analysis of the device are performed using the finite-difference time-domain method (FDTD). Transfer functions between pairs of input and output ports are calculated and used to define the design metrics

Frequency-diverse multimode millimetre-wave constant-\u03f5r lens-loaded cavity

This paper presents a physical frequency-diverse multimode lens-loaded cavity, designed and used for the purpose of the direction of arrival (DoA) estimation in millimetre-wave frequency bands for 5G and beyond. The multi-mode mechanism is realized using an electrically-large cavity, generating spatio-temporally incoherent radiation masks leveraging the frequency-diversity principle. It has been shown for the first time that by placing a spherical constant dielectric lens (constant-ϵr) in front of the radiating aperture of the cavity, the spatial incoherence of the radiation modes can be enhanced. The lens-loaded cavity requires only a single lens and output port, making the hardware development much simpler and cost-effective compared to conventional DoA estimators where multiple antennas and receivers are classically required. Using the lens-loaded architecture, an increase of up to 6 dB is achieved in the peak gain of the synthesized quasi-random sampling bases from the frequency-diverse cavity. Despite the fact that the practical frequency-diverse cavity uses a limited subset of quasi-orthogonal modes below the upper bound limit of the number of theoretical modes, it is shown that the proposed lens-loaded cavity is capable of accurate DoA estimation. This is achieved thanks to the sufficient orthogonality of the leveraged modes and to the presence of the spherical constant-ϵr lens which increases the signal-to-noise ratio (SNR) of the received signal. Experimental results are shown to verify the proposed approach.

Design and analysis of optical logic gates based on trifurcation structured 2D photonic crystals

In this paper, a trifurcation structured optical logic gates is designed based on 2D photonic crystals that is composed of square lattice air holes in silicon. The results of the proposed structure confirm that it could exhibit the optical logic gate functionality of OR, AND, NOR and NAND gates. These gates were designed with three inputs port and single output port. Out of the three inputs, the centre port is considered as the reference input. The inputs are followed by a square shaped resonator design. The bit rate and footprint are calculated for the proposed optical logic gates. The contrast ratio for AND, NAND and NOR gate is 6.15 dB, 5.79 dB and 2.97 dB respectively. Additionally, phase shifts are introduced in the launch field to improve the contrast ratio and it is found that certain logic functions display improved power output. The contrast ratio for AND, OR gate (with 180° phase shift) is 6.52 dB and 10.79 dB, respectively. The footprint for the proposed gate is 424.7 μm. Plane wave expansion and finite difference time domain method are used to calculate the band structure and wave propagation of the structure.

Highly efficient compact gigawatt‐level microwave source using relativistic electrons: radial relativistic magnetron

The relativistic magnetron is one of the most attractive high-power microwave sources, due to its compactness with high efficiency. It can generate hundreds of megawatts of microwave power in the L- and S-bands. However, the efficiency of the magnetron is often limited due to the mode stability. In this Letter, three-dimensional particle-in-cell simulation suggests even further increase of total efficiency of the magnetron can be realised via mode stabilisation using a self-excited extended interaction in a collector region. A six-vaned radial relativistic magnetron with a single radial output port powered by 400 kV, 900 MW with an efficiency of ∼48%. This improvement is attributed to the mode locking of operating π-mode by a power-boosted TE315 mode excited in the extended cavity.

Resolving Photon Numbers Using a Superconducting Nanowire with Impedance-Matching Taper.

Time- and number-resolved photon detection is crucial for quantum information processing. Existing photon-number-resolving (PNR) detectors usually suffer from limited timing and dark-count performance or require complex fabrication and operation. Here, we demonstrate a PNR detector at telecommunication wavelengths based on a single superconducting nanowire with an integrated impedance-matching taper. The taper provides a kΩ load impedance to the nanowire, making the detector's output amplitude sensitive to the number of photon-induced hotspots. The prototyping device was able to resolve up to four absorbed photons with 16.1 ps timing jitter and <2 c.p.s. device dark count rate. Its exceptional distinction between single- and two-photon responses is ideal for high-fidelity coincidence counting and allowed us to directly observe bunching of photon pairs from a single output port of a Hong-Ou-Mandel interferometer. This detector architecture may provide a practical solution to applications that require high timing resolution and few-photon discrimination.

Differential Sensing Based on Quasi-Microstrip Mode to Slot-Mode Conversion

In this letter, a differential sensor and comparator based on a mode conversion detector implemented by means of a slotline resonator is proposed for the first time. The sensor divides the input signal between two identical sensing elements, a pair of microstrip lines loaded with complementary split-ring resonators (CSRRs). Such CSRRs are symmetrically etched in the ground plane at both sides of the slotline. Therefore, by truncating symmetry, e.g., by loading one of the CSRRs with the reference (REF) sample and the other one with the sample under test (SUT), the slot mode is generated in the slotline resonator. The signal level associated with this mode, which can be inferred by means of a slotline/microstrip transition, depends on the level of asymmetry generated by CSRR loading. Consequently, the proposed structure is useful for differential sensing, where a single input and output port suffices to excite the sensor and to measure the output variable, the magnitude of the transmission coefficient.

A reconfigurable five-port power divider with power routing versatility

This paper presents a reconfigurable five-port power divider with power routing versatility. The divider provides three transmission modes: direct transmission to a single output port, equal power division between two outputs, and four-way equal division. Selecting the desired transmission mode is realized by reconfiguring six reactive loads connected to the core structure of the divider. The analytical S-parameters of the proposed divider are derived using even-odd analysis, and are utilized by a numerical optimization routine to find the design parameters required to achieve acceptable performance. A prototype operating at 3 GHz, which realizes the reconfigurable reactive loads using varactor diodes, is fabricated for verification of the concept. Simulation and measurement results of the power divider prototype are presented, and demonstrate good performance in terms of insertion loss (deviation ⩽1.3 dB from the ideal values), input return loss (⩾10 dB), and isolation (⩾14 dB) between the input and the non-transmitting ports. The proposed divider can be used in antenna selection schemes and as a single-pole quadruple-throw switch.

Modeling and Simulation of the Intrinsic Function of a Photonic Switch

In this paper, I provide modeling and simulation results which show that a photonic bistable switch can be realized by the application of two superluminescent light emitting diodes to a configuration of three 10μm radius micro-ring resonators. The 130nm silicon on insulator rib structure is adopted for the simulations. The three 10μm radius rings have a resonant wavelength of 1.5487μm. The on or off state, at a single output port, is realized by the application of a superluminescent diode at either, one or the other, of the two input ports. The bistable output intensity, at the ring resonant wavelength, is shown as a single normalized peak representing a 1 or the “on” condition. The single peak is realized by the application of the “on” superluminescent diode. The “off” or the 0 condition, realized by the application of the “off” superluminescent diode, is exhibited at the output by the introduction of an optical transparency at the single peak resonant wavelength. The minimum of the optical transparency can be adjusted by changing the coupling gap distances of the design. The transparency mimum introduces an error detection feature whereby a failure of the “off” excitation superluminecent diode results in a zero or noise floor output. The transparency minimum can be increased to raise the off state minimum above the measurement apparatus noise floor. The output of the switch can be detected using a simple photodiode intensity detection method.

Synthesis of Orchestrations of Transducers for Manufacturing

In this paper, we model manufacturing processes and facilities as transducers (automata with output). The problem of whether a given manufacturing process can be realized by a given set of manufacturing resources can then be stated as an orchestration problem for transducers. We first consider the conceptually simpler case of uni-transducers (transducers with a single input and a single output port), and show that synthesizing orchestrations for uni-transducers is EXPTIME-complete. Surprisingly, the complexity remains the same for the more expressive multi-transducer case, where transducers have multiple input and output ports and the orchestration is in charge of dynamically connecting ports during execution.

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors.

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.

A Wide-Range Multiport LC-Ladder Oscillator and Its Applications to a 1.2–10.1 GHz PLL

This brief presents a wide-range multiport LC-ladder resonator and its application to phase-locked loop (PLL). The multiport LC-ladder structure provides a high-order resonator, which has multiple resonance frequencies. The output frequency can be discretely altered from these resonance frequencies through enabling or disabling the active devices of various ports. The capacitor bank provides continuous frequency tuning to cover the gaps between the resonance frequencies. Thus, the oscillator seamlessly achieves a wide frequency coverage. The ports of the LC-ladder resonator are series connected with inductors. The oscillator can be a single output port, and avoids output multiplexing. The structure and behavior of the resonator are discussed and analyzed in this brief. A PLL with a three-port LC-ladder oscillator is fabricated with 65-nm CMOS technology to demonstrate this concept. The core circuit occupies a silicon area of 0.4 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measured output frequency ranges from 1.2 to 10.1 GHz. Phase noise at 1 MHz of all frequencies is below -96 dBc/Hz. The proposed voltage-controlled oscillator consumes less than 8 mW from a 1.2 V supply voltage in all of the operational modes.

Fully digitally programmable voltage mode universal filter

This paper presents a novel voltage mode universal filter (UF) using digitally programmable current feedback amplifier. The proposed filter configuration uses only one input variable and realizes all the five filter functions at single output port only. Generation of all the filter functions (types) at the single output port is governed digitally The UF is fully programmable as all the filter functions (types) and their parameters are independently programmable. Other salient features of UF include full cascadability by virtue of appropriate input/output port impedance and use of two grounded capacitors only.

Three-visible-light wave combiner based on photonic crystal waveguides.

We present a three-visible-light wave combiner based on two-dimensional photonic crystal waveguides whose widths are not integral multiples of the lattice period. The proposed device consists of two cascaded directional couplers. It combines three visible light waves with different wavelengths from three input ports into a single output port. As an example, a combiner for combining light waves of 635, 532, and 488 nm, which are commonly used as the three primary colors in laser display systems, is designed and demonstrated through the finite-difference time-domain method. The results show that the proposed device can perform efficient synthesis for three visible light waves with transmittance exceeding 89% for each wavelength and high ability in preventing the backward coupling of waves from different waveguides. The method for designing the combiner is useful for designing other waveguide couplers based on photonic crystals made of dispersion materials.