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In this paper, the evolution of the microstructure for the zinc silicate ceramics with different Zn/Si ratios was revealed, and the factors influencing their dielectric properties were discussed. Our results demonstrate that Zn volatilization plays an important role on the defect structure of the samples. Low relative density, high conductivity loss caused by volatilization, and the presence of ZnO phase collectively result in low quality factor (Qf) of Zn 2.0 SiO 4.0. By using the powder embedded sintering method, the loss could be reduced owing to the suppression of volatilization. As the Zn/Si ratio decreases, the ZnO disappears, while the Si-rich phase emerges and increases. The formation of a liquid phase results in a dense microstructure of the non-stoichiometric samples. Moreover, these samples exhibit a minor degree of Zn loss, probably because the presence of liquid phase constraints the volatilization during sintering. The samples with x = 1.8 display desirable properties, including a relative dielectric constant (ε r) of 6.5, a Qf of 100,800 GHz, and a temperature coefficient of resonant frequency (τ f) of −21.3 ppm/°C, due to their high degree of densification, slight zinc loss, and the elimination of the ZnO phase. [ABSTRACT FROM AUTHOR]

The rapid preparation of high-performance microwave dielectric ceramics has always been a technical challenge in the field of electronic ceramics. In this investigation, we rapidly fabricate MgTiO 3 –CaTiO 3 microwave ceramics with homogenous microstructure and high quality factor Q by microwave-assisted sintering, highlighting the efficiency gains and sintering time reductions. As the sintering time increases from 15 min to 45 min, the bulk density and relative density of MT-CT ceramic rapidly increase. The relative density of samples sintered for 30 min exceeds 97 %, which is difficult to achieve through conventional sintering methods. Combined with Rietveld refinement and Raman spectra, it is confirmed that the cell volume of MT-CT ceramics shrinks with the extension of sintering time, resulting in the weaken of Ti–O bond strength. More refined grain size distribution and uniform microstructure obtained by microwave-assisted sintering are likely to be pivotal factors in enhancing the microwave dielectric properties of MT-CT ceramics. MT-CT ceramics sintered at 1300 °C for only 45 min by microwave-assisted sintering exhibit excellent dielectric properties: Q×f = 87, 300 GHz, ε r = 20.42, and τ f = 2.11 ppm/°C, thereby demonstrating the potential of achieving rapid densification of microwave ceramics through microwave-assisted sintering. [ABSTRACT FROM AUTHOR]

The microsensor is modeled as a two-layer micro beam in which the first layer is quartz and the second layer is silicon. This beam is clamped-free and beam has a rectangular cross-section. Sensitivity and quality factors which are two important functions in sensors are selected as objective functions. Dimensions of the micro beam are design variables, so this optimization has two functions and four variables of the design. Objective functions are depended on the natural frequency, material properties, and dimensions of the beam. The natural frequency is obtained according to the modified couple stress theory by using Rayleigh's method. Optimization is done by using genetic algorithm. Results show the length of the beam has a significant effect on the sensitivity and quality factor. Also, it can be seen that when dimensions of the beam decrease, sensitivity increases, and quality factor decreases. Results are presented based on non-classical and the classical theories. [ABSTRACT FROM AUTHOR]

This study focuses on optimizing the resonator geometry via the aspect ratio design of a width-extensional mode resonator to improve its quality factor (Q), which is one of the critical performance parameters for resonators in either sensing (Allan deviation) or frequency reference (phase noise) applications. The proposed approach uses finite element analysis to reduce the strain energy at anchor supports by altering the resonator geometric structure, thereby reducing energy loss through anchors. Moreover, process limitations on feature sizes are used as constraints to find aspect ratios that can not only increase the Q but also reduce spurious modes near the targeted frequency. The devices were fabricated using AlN thin film piezoelectric on a substrate (TPoS) process. The simulated energy dissipation trends for specific length-to-width (L / W) ratios closely match the measured changes in the resonator Q values in vacuum. In vacuum, the highest Q -factor achieved by the device is close to 8816, with a motional resistance of a few tens of ohms. Additionally, a board-level oscillator realized using a commercial low-noise amplifier exhibits phase noise performance of −141.21 dBc Hz−1 and −164.25 dBc Hz−1 at 1 kHz and 1 MHz frequency offsets, respectively. The calculated figures of merit for these offsets are 204 and 168, respectively. [ABSTRACT FROM AUTHOR]

Low microwave loss and regulatable kinetic inductance are two key characteristics of superconducting films to manufacture high-performance quantum devices. Epitaxial titanium nitride (TiN) thin films have been found to exhibit significant advantages in these two aspects. In this paper, we investigated into the dielectric loss and kinetic inductance of epitaxial TiN films, which were prepared on both silicon and sapphire substrates with different temperatures. Crystal structure, surface morphology, and superconducting properties were characterized systematically. The radio-frequency response of microwave resonators made of TiN films was studied at low temperatures to extract the information of kinetic inductance and quality factor. We obtained the highest internal quality factor up to 1.6 × 10 6 at single photon regime and achieved a regulation of kinetic inductance exceeding 16 times by altering the substrate and the sputtering temperature of the TiN films. This work not only provides an essential foundation for the precise design and preparation of low-loss TiN resonators for superconducting quantum bits, but also demonstrates TiN film as an excellent material platform with both low microwave loss and high kinetic inductance that can be applied in other fields such as microwave kinetic inductance detectors. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study and performance analysis of all-oxide thin-film Au/Pt/Ba 0.5 Sr 0.5 TiO 3 /SrMoO 3 varactors with 100 nm Ba 0.5 Sr 0.5 TiO 3 (BST) tunable dielectric layers doped with 1%, 3% and 5% of Mn and Ni grown epitaxially on a 600 nm SrMoO 3 bottom electrode. Performance parameters such as tunability, quality factor, figure-of-merit, leakage current and acoustic resonances of the varactors are investigated. The investigation covers frequencies up to 6 GHz and a broad temperature range from − 40 ∘ to 80 ∘ , using biasing field strengths of up to ± 100 V/μm, in order to evaluate the feasibility and the performances of BST-doped all-oxide varactors for sub-6 GHz applications. Results confirm the anticipated advantages of Mn and Ni doping: a substantial reduction in leakage current along with an increase in quality factor, however, at the cost of reduced tunability. The observed acoustic resonances are shifted towards higher frequencies as compared to those for varactors with undoped BST, which implies in a larger frequency operating range for doped all-oxide varactors. In addition, the amplitudes of the acoustic resonances decline with doping. Moreover, they can be effectively suppressed for thinner BST layers, which has been proved exemplarily for a varactor with a 25 nm Mn-doped BST layer and a tunability of 55 %, requiring an ultimately low tuning voltage of only 2.9 V. [ABSTRACT FROM AUTHOR]

Ba1 − xSrxMg2 − yZnyV2O8 compounds, abbreviated as BSMZVO@xy (x = 0.0–0.2 and y = 0.02), were synthesized with tetragonal structures. The microstructure, molecular structure, and polarization mechanism were investigated using X‐ray diffraction, electronic microscopy, Raman spectroscopy, and vector network analyzer. The sintering temperatures (<900°C) and microwave dielectric properties of BSMZVO are significantly impacted by (Sr/Zn)2+ substitution and TiO2 mixing. The BSMZVO@xy (x = 0.15 and y = 0.02) exhibited encouraging εr (12.4–12.7), Q × f (40 054–40 973 GHz), and temperature coefficient of resonance frequency (τf ∼ −5.2 to 0.0 ppm/°C) after sintering at 860°C/4 h and 800°C/4 h. For the first time, TiO2 was added to enhance the density and Q × f value without degrading τf. The 0.25 wt.% TiO2 resulted in optimum εr of 13.4, Q × f of 43 636 GHz, and τf of +1.8 ppm/°C after sintering at 760°C/4 h. The improved quality factor (Q × f) is linked to the Raman A1g mode and relative density. [ABSTRACT FROM AUTHOR]

Achieving comprehensive improvement in both piezoelectric coefficient (d33) and mechanical quality factor (Qm) has become a key issue in the research of high‐power piezoelectric ceramics. Here, we focused on Mn‐doped Pb(In1/2Nb1/2)O3‐Pb(Sc1/2Nb1/2)O3‐PbTiO3 (PIN‐PSN‐PT) relaxor ferroelectric ceramics, where Mn‐doping is employed to enhance Qm. The effects of doping concentration and PT content on phase structure, ferroelectric, dielectric, and electromechanical properties were systematically studied. The well radius matching between Mn ions and B‐site ions facilitates the ion substitution and significantly increases the concentration of oxygen vacancies, thereby enhancing the domain wall pinning effect. A significantly weakened mutual constraint relationship between d33 and Qm is observed in the 2 mol% Mn‐doped PIN‐PSN‐PT ceramics with tetragonal phase, which exhibits Qm exceeding 3000 while maintaining d33 higher than 320 pC/N and Curie temperature higher than 300°C, leading to the vibration velocity over 1.15 m/s. Rayleigh analysis reveals the higher intrinsic piezoelectric response in high PT components compared to that in low PT components, which was thought to be the origin for the weakened mutual constraint relationship between d33 and Qm in tetragonal Mn‐doped PIN‐PSN‐PT ceramics. [ABSTRACT FROM AUTHOR]

In low-to-moderately active seismic regions such as the Korean Peninsula, it is difficult to analyze seismic hazards because only a limited number of strong ground motions have been recorded. To address this shortcoming in the data, ground motion simulation can be used to generate the strong ground motions associated with potentially large earthquakes, taking into account the attenuation that occurs as the distance from the source increases. To simulate this attenuation, the path effect, which is a component of the Fourier amplitude spectrum (FAS), needs to be defined, along with the source and site effects. The path effect represents the propagation of seismic rays through a tectonic medium. In this study, a three-dimensional (3D) path effect model is developed for the Korean Peninsula, consisting of a 3D geometrical spreading factor, quality factor, and shear-wave velocity. The accuracy of the proposed model is verified by comparing the path-effect values obtained from the FAS of individual ground motions recorded on the Korean Peninsula and those calculated from the model. Examples that demonstrate the procedure to calculate the 3D path effect for the Korean Peninsula are also provided. [ABSTRACT FROM AUTHOR]

Ba1 − xSrxMg2 − yZnyV2O8 compounds, abbreviated as BSMZVO@xy (x = 0.0–0.2 and y = 0.02), were synthesized with tetragonal structures. The microstructure, molecular structure, and polarization mechanism were investigated using X‐ray diffraction, electronic microscopy, Raman spectroscopy, and vector network analyzer. The sintering temperatures (<900°C) and microwave dielectric properties of BSMZVO are significantly impacted by (Sr/Zn)2+ substitution and TiO2 mixing. The BSMZVO@xy (x = 0.15 and y = 0.02) exhibited encouraging εr (12.4–12.7), Q × f (40 054–40 973 GHz), and temperature coefficient of resonance frequency (τf ∼ −5.2 to 0.0 ppm/°C) after sintering at 860°C/4 h and 800°C/4 h. For the first time, TiO2 was added to enhance the density and Q × f value without degrading τf. The 0.25 wt.% TiO2 resulted in optimum εr of 13.4, Q × f of 43 636 GHz, and τf of +1.8 ppm/°C after sintering at 760°C/4 h. The improved quality factor (Q × f) is linked to the Raman A1g mode and relative density. [ABSTRACT FROM AUTHOR]

Within recent years, the field of nano-mechanics has diversified in a variety of applications, ranging from quantum information processing to biological molecules recognition. Among the diversity of devices produced these days, the simplest (but versatile) element remains the doubly clamped beam: it can store very large tensile stresses (producing high resonance frequencies f 0 and quality factors Q), is interfaceable with electric setups (by means of conductive layers), and can be produced easily in clean rooms (with scalable designs, including multiplexing). Besides, its mechanical properties are the simplest to describe. Resonance frequencies and Q s are being modeled, with as specific achievement the ultrahigh quality resonances based on "soft clamping" and "phonon shields." Here, we demonstrate that the fabrication undercut of the clamping regions of basic nano-beams produces "natural soft clamping," given for free. We present the analytic theory that enables to fit experimental data, which can be used for { Q , f 0 } design: beyond finite element modeling validation, the presented expressions provide a profound understanding of the phenomenon, with both Q enhancement and a downward frequency shift. [ABSTRACT FROM AUTHOR]

By consistently applying the formalism of quantum electrodynamics, we developed a comprehensive theoretical framework describing the interaction of single microwave photons with an array of superconducting transmon qubits in a waveguide cavity resonator. In particular, we analyze the effects of microwave photons on the array's response to a weak probe signal exciting the resonator. The study reveals that high quality factor cavities provide a better spectral resolution of the response, while cavities with moderate quality factors allow better sensitivity for a single-photon detection. Remarkably, our analysis showed that a single-photon signal can be detected by even a sole qubit in a cavity under the realistic range of system parameters. We also discuss how the quantum properties of the microwave radiation and electrodynamical properties of resonators affect the response of qubits' array. Our results provide an efficient theoretical background for informing the development and design of quantum devices consisting of arrays of qubits, especially for those using a cavity where an explicit expression for the transmission or reflection is required. [ABSTRACT FROM AUTHOR]

To break the limitation of large mass required for low-frequency topologically protected interface modes (TPIMs), a novel inertial amplified topological metamaterial beam is proposed in this work. Detailed analytical and numerical studies are conducted to investigate the dynamic characteristic of this system. The Dirac cone (DC) is formed at the boundary of the Brillouin zone through the zone-folding method. Thanks to the inertial amplification mechanism, the lower-frequency DC and wider local resonance bandgaps (LRBGs) are obtained without sacrificing total stiffness or increasing total mass. Besides, the DC and LRBG can be tuned effectively by the arm length ratio of the lever. In order to realize the TPIM, two topologically distinct supercells are constructed by space modulation of resonators. Transmission simulation confirms the existence of TPIM between two domains with different topological properties. The energy concentration of TPIM is quantified by the quality factor. Moreover, the tunability and robustness of TPIM are also verified. Besides, to further enlarge the response area of TPIM, the sandwich structure is proposed. Although the peak displacement is reduced with the enlargement of response area, the displacement is still well confined within the sandwich layers. This novel inertial amplified topological metamaterial beam is expected to promote the application of topological devices, especially in the low-frequency lightweight challenging conditions. [ABSTRACT FROM AUTHOR]

The first asymmetric mode (A1 mode) lamb wave resonator (LWR) with a resonant frequency of 6 GHz based on Z-cut lithium niobate (LN) films is presented. An asymmetric electrode structure with different-sized electrode pads in the center and edged regions has been proposed, which can be used to optimize the distribution of the electric field and decrease acoustic impedance mismatch to improve the target mode. Experiment results reveal that LWRs with an asymmetric electrode structure can successfully enhance the A1 mode, achieving a high effective electromechanical coefficient ( k eff 2 ) of 26%, a quality factor (Q) of 1123, and an excellent figure-of-merit (FOM = k eff 2 ∙ Q) of 262. It demonstrates that asymmetric electrode structure provides a new way to suppress the spurious modes for LWRs and shows a great application prospect in wide-bandwidth and low-loss filters used in the sub-6 G frequency range. [ABSTRACT FROM AUTHOR]

Gallium Phosphide (GaP) has recently received considerable attention as a suitable material for building photonic integrated circuits due to its remarkable optical and piezoelectric properties. Usually, GaP is grown epitaxially on III–V substrates to keep its crystallinity and later transferred to silicon wafers for further processing. Here, an alternative promising route for the fabrication of optomechanical (OM) cavities on GaP epitaxially grown on nominally (001)‐oriented Si is introduced by using a two‐step process consisting of a low‐temperature etching of GaP followed by selective etching of the underneath silicon. The low‐temperature (–30 °C) during the dry‐etching of GaP hinders the lateral etching rate, preserving the pattern with a deviation between the design and the pattern in the GaP layer lower than 5%, avoiding the complex process of transferring and bonding a GaP wafer to a silicon‐on‐insulator wafer. To demonstrate the quality and feasibility of the proposed fabrication route, suspended OM cavities are fabricated and experimentally characterized. The cavities exhibit optical quality factors between 103 and 104 at telecom wavelengths, and localized mechanical resonances ≈3.1 GHz with quality factors ≈63 when measured at room temperature. These results suggest a simple and low‐cost way to build GaP‐based photonic devices directly integrated on industry‐standard Si(001) photonic wafers. [ABSTRACT FROM AUTHOR]

High-k Ba4Sm28/3Ti18O54 ceramics with improved microwave dielectric characteristics were successfully fabricated using the one-step reaction sintering (RS) route. The sintering characteristics, microstructure, crystal structure, infrared reflection spectrum, and microwave dielectric characteristics of Ba4Sm28/3Ti18O54 ceramics prepared by the RS route were systematically investigated. Samples prepared by the RS route exhibited single-phase orthorhombic tungsten–bronze structure and dense microstructure at optimum sintering temperature. Compared with the conventional solid-state (CS) process, the Ba4Sm28/3Ti18O54 ceramics fabricated by the RS route presented a smaller temperature coefficient (TCF), a higher quality factor (Q × f), and a higher permittivity (εr). The improved microwave dielectric characteristics were highly dependent on the theoretical permittivity, atomic packing fraction, suppression of Ti3+, and Ti-site bond valence. Excellent combined microwave dielectric characteristics (TCF = −7.9 ppm/°C, Q × f = 9519 GHz, εr = 80.26) were achieved for Ba4Sm28/3Ti18O54 ceramics prepared by RS route sintered at 1400 °C, suggesting the RS route was a straightforward, economical and effective route to prepare high-performance Ba4Sm28/3Ti18O54 ceramics with promising application potential. [ABSTRACT FROM AUTHOR]

In this study, Ba(Mg 1/3 Ta 2/3)O 3 (BMT) ceramics added with different amounts of CaO–B 2 O 3 –ZnO (CBZ) glass were prepared through the solid-state sintering route. The sintering behavior, microstructure, phase composition and dielectric properties of the BMT ceramics added with CBZ glass were investigated. The addition of CBZ glass decreased the sintering temperature of BMT ceramics by over 300 °C, resulting in a highly dense microstructure without interacting with the main BMT phase. The lower sintering temperature led to small ceramic grains and caused a decrease in the Q × f value. Prolonging the sintering time improved the ordering degree of cations on the B-site in BMT ceramic, leading to an enhancement in the Q × f value. The BMT ceramic added with 0.4 wt% CBZ glass exhibited excellent microwave dielectric properties: ε r = 24.19, Q × f = 115,100 GHz, τ f = 9.84 ppm/°C, after sintering at 1400 °C for 12 h. [ABSTRACT FROM AUTHOR]

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In optical communication and sensing, silicon nitride (SiN) photonics plays a crucial role. By adeptly guiding and manipulating light on a silicon-based platform, it facilitates the creation of compact and highly efficient photonic devices. This, in turn, propels advancements in high-speed communication systems and enhances the sensitivity of optical sensors. This study presents a comprehensive exploration wherein we both numerically and experimentally display the efficacy of a SiN-based ring resonator designed for refractive index sensing applications. The device's sensitivity, numerically estimated at approximately 110 nm/RIU, closely aligns with the experimental value of around 112.5 nm/RIU. The RR sensor's Q factor and limit of detection (LOD) are 1.7154 × 104 and 7.99 × 10−4 RIU, respectively. These congruent results underscore the reliability of the two-dimensional finite element method (2D-FEM) as a valuable tool for accurately predicting and assessing the device's performance before fabrication. [ABSTRACT FROM AUTHOR]

Topological photonics shows considerable promise in revolutionizing photonic devices through the use of topological phases, leading to innovations like topological lasers that enhance light control. One of the recent breakthroughs is reducing the size of these systems by utilizing lower‐dimensional boundary states, notably via higher‐order topological phases. This paper presents the experimental demonstration of a topological laser in an anomalous quadrupole topological phase, an instance of higher‐order phases. To facilitate this, a topological nanocavity with a quality factor near 6000 is engineered through a twisting operation. The topological nature of this system is validated by the calculation of nested Wannier centers and the emergency condition of corner states. The experimental observations reveal the manifestation of corner states and the achievement of single‐mode pulsed laser, driven by an optical gain from multiple quantum wells at telecommunication wavelengths and a temperature of 4 K. A lasing threshold of 23 µW and a cold quality factor of 1500 are deduced through rate equation. This work gives a new potential in the application of topological principles to advance nanophotonic technologies. [ABSTRACT FROM AUTHOR]

We report on the experimental demonstration of aluminum scandium nitride (AlScN)-on-cubic silicon carbide (3C-SiC) Lamb wave resonators (LWRs) realized via microelectromechanical systems (MEMS) technology, operating at high temperature (T) up to T = 800 °C, while retaining robust electromechanical resonances at ∼27 MHz and good quality factor of Q ≈ 900 even at 800 °C. Measured resonances exhibit clear consistency and stability during heating and cooling processes, validating the AlScN-on-SiC LWRs can operate at high T up to 800 °C without noticeable degradation in moderate vacuum (∼20 mTorr). Even after undergoing four complete thermal cycles (heating from 23 to 800 °C and then cooling down to 23 °C), the devices exhibit robust resonance behavior, suggesting excellent stability and suitability for high-temperature applications. Q starts to decline as the temperature exceeds 400 °C, which can be attributed to energy dissipation mechanisms stemming from thermoelastic damping and intrinsic material loss originating from phonon–phonon interactions. [ABSTRACT FROM AUTHOR]

Theoretical studies on the vibration of microcantilever beams in fluids, which are commonly used in micro- and nanoelectromechanical systems (MEMS/NEMS). When microcantilever beams are subjected to photo-thermal excitation, they show that the material properties such as the dynamic response and the one-dimensional temperature field will show significant differences from the macroscopic properties when the size appearance of the microbeam decreases to the scale below a dozen micrometers. In this paper, by correcting the scale constants of the beams, the photothermal vibration model of the microbeam is established using the physical neutral plane theory. The one-dimensional heat transfer equations and scale-corrected temperature field of the microcantilever beam under laser excitation are derived, which are solved by Galerkin’s method, based on the theory of thermoelasticity, the hydrodynamic model of the beams vibrating in incompressible liquids proposed by Sader et al. and the theory of Euler–Bernoulli beams. The equations governing the vibration of micro-cantilever beams corrected for scale effects in different fluids when subjected to photothermal excitation are obtained. The results show that the temperature field, resonant frequency, and quality factor of the microbeam will have a significant upward drift when the size of the microbeam is close to the scale parameter, and the scale effect has a non-negligible influence on the macroscopic performance parameters; the upward drift is gradually weakening when the thickness to scale ratio gradually increases. Finally, the property of the beam is almost the same as that of the theory when the thickness of the beam is 10 times the scale constant. The correction of the theory by the scale effect is insignificant. [ABSTRACT FROM AUTHOR]

Introduction/purpose: This paper presents the results of the research on visually lossless image compression which is of particular interest because it achieves a high degree of compression, while the visual quality of the image is not impaired, i.e., end users are very satisfied with the image quality. The analysis was carried out using the publicly available large-scale picture-wise KonJND-1k database which contains the results of subjective tests on JPEG and BPG compressed images. Methods: Thanks to the availability of images from the KonJND-1k database, the dependence of objective assessments of image quality on parameters that control the degree of compression of source signals (quality factor for JPEG and quantization parameter for BPG) is analyzed. The results of the visually lossless subjective tests are used for a deep analysis of the boundary and typical values of the parameters that control these two types of compression, as well as for the analysis of the corresponding values of the objective quality scores. Furthermore, reliable features for predicting the boundary between visually lossless and visually lossy compression have been identified. For that purpose, the degree of agreement between the predictions and the ground truth values of the peak signal-to-noise ratio (PSNR) and image representation in bits per pixel (bpp) is used. The visually lossless compression ratio is used to compare JPEG and BPG techniques. Results: It is shown that the boundary between visually lossless and visually lossy image compression is found in a wide range of PSNR values (about 20 dB for JPEG and 15 dB for BPG). The corresponding JPEG image compression quality factor values at this threshold also range widely from 31 to 79, with concentration between 40 and 45. For the BPG encoder, the values of the quantization parameter are grouped around 30, and the boundary values are 25 and 34. Furthermore, it is shown that this boundary can be reliably determined based on simple features derived from the original uncompressed image. Gradient-based features known as spatial frequency and spatial information proved to be the best predictors. The degree of agreement between the predictions obtained from these features with the ground truth values of PSNR and bpp in both types of compression is greater than 85%. A comparative analysis has showed that, using BPG compression, it is possible, on the average, to achieve a twice larger compression ratio of visually lossless compression than for JPEG (80 versus 40). Conclusion: Although a high degree of agreement is achieved between the predictions and the ground truth values of PSNR and bpp of the boundary between visually lossless and visually lossy compression, there is a need for the development of new prediction approaches, especially with the BPG technique, which through the compression ratio proved to be superior to the JPEG technique. The existing databases used for the analysis of visually lossless compression contain color images from the visible part of the electromagnetic spectrum. Considering the increasing use of images from the infrared part of the spectrum, there is a need to conduct similar tests in this spectral range. [ABSTRACT FROM AUTHOR]

Superconducting detectors play a crucial role in astronomy, particularly at millimeter and sub-millimeter wavelengths, due to their high sensitivity, ease of fabrication, and potential for integration into large arrays. Josephson junction detectors, which utilize high-temperature superconductors, offer a promising design option because they can operate at higher temperatures. In this paper, we aim to design and simulate two detectors based on high-temperature Josephson junctions for millimeter and sub-millimeter waves. To achieve this goal, we employed the Riblet directional coupler to develop detector arrays. We evaluated the frequency response, quality factor, and loss in these detectors. The experimental results indicate that constructing larger arrays and reducing the gap between the coupler and resonators can enhance the quality factor. We demonstrate this improvement by presenting the quality factors for two different gaps in each spectrum. [ABSTRACT FROM AUTHOR]

This study reassesses an overview of the potential of the radio frequency (RF)-based state diagnostics of three-way catalysts (TWC) based on a previous study with an emphasis on the defect chemistry of the catalyst material during reoxidation and reduction. Some data are based on the previous works but are newly processed, and the signal parameters resonant frequency and inverse quality factor are evaluated with respect to applicability. The RF-based method uses electromagnetic resonances in a cavity resonator to provide information on the storage level of the oxygen storage component. The analysis focuses on a holistic investigation and evaluation of the major effects influencing the RF signal during operation. On the one hand, the response to the oxygen storage behavior and the resolution of the measurement method are considered. Therefore, this study merges original data from multiple former publications to provide a comprehensive insight into important measurement effects and their defect chemistry background. On the other hand, the most important cross-sensitivities are discussed and their impact during operation is evaluated. Additionally, the effect of catalyst aging is analyzed. The effects are presented separately for the two resonant parameters: resonant frequency and (unloaded) quality factor. Overall, the data suggest that the quality factor has a way higher signal quality at low temperatures (<400 °C) and the resonant frequency is primarily suitable for high operating temperatures. At most operating points, the quality factor is even more robust against interferences such as exhaust gas stoichiometry and water content. Correctly estimating the catalyst temperature is the most important factor for reliable results, which can be achieved by combining the information of both resonant signals. In the end, the data indicate that microwave-based state diagnosis is a powerful system for evaluating the oxygen storage level over the entire operating range of a TWC. As a research tool and in its application, the system can therefore contribute to the improvement of the emission control of future gasoline vehicles. [ABSTRACT FROM AUTHOR]

The zinc orthosilicate, Zn2SiO4 ceramics, exhibit great potential as microwave dielectric materials due to their low dielectric constant and ultrahigh quality factor. The solid‐state synthesis of Zn2SiO4 ceramics often results in the presence of a secondary phase of ZnO, however, leading to significantly lower Q×f values. Cold‐isostatic‐pressing (CIP) and nonstoichiometry have been proven effective in purifying the Zn2SiO4 but need elaborate process and composition manipulation. In this work, it was found that the particle size of SiO2 plays a crucial role in purifying the Zn2SiO4 phase. Specially, nano‐sized SiO2 particles (15 and 30 nm) led to the formation of a ZnO secondary phase in synthesized Zn2SiO4 ceramics, while micro‐sized (2 and 10 µm) resulted in pure‐phase Zn2SiO4 with excellent microwave properties. Notably, when prepared with 10 µm SiO2 and sintered at 1 340°C, the resulting Zn2SiO4 exhibited outstanding microwave performances with a Q×f value of 122 570 GHz, a temperature coefficient of frequency τf of −51.9 ppm/°C, and a dielectric constant (εr) of 6.5. These findings highlight the importance of controlling particle size during synthesis to achieve desired material properties such as purity and excellent microwave performances. [ABSTRACT FROM AUTHOR]

Thermoelastic damping (TED) is a fundamental dissipation mechanism that inevitably exists in high-performance micro/nano-electro-mechanical systems. In this paper, the damping characteristics in semiconductor microbeam are studied under coupled carrier-thermo-elastic theory. Using conventional LR model and considering the effect of carrier, the governing equations for TED in semiconductor beam were obtained and the analytical solution for temperature and carrier density was obtained using complex frequency method. The expression for inverse quality factor was given by solving the vibration equation. The effects of cantilever beam size, material parameters, temperature, and doping concentration on TED were studied, and the results showed that the carrier has significant influence on the dissipation performance of semiconductor microstructures. The study also indicated that when carrier characteristics are ignored, this conclusion can degenerate into classical TED results under LR model. [ABSTRACT FROM AUTHOR]

A master oscillator power amplifier (MOPA) pulsed laser operating at 1342 nm is demonstrated. It consists of an acousto-optical (A-O) Q-switched oscillator and two-stage Nd: YVO4 power amplifiers. The spherical aberration self-compensation technique is used in the second stage amplifier to obtain high-beam-quality laser output. The maximum average output power of 20.4 W is obtained with the oscillator power of 2.0 W and the total pump light power of 184.08 W, corresponding to an optical-optical efficiency of 11.08%. The repetition rate and pulse width are 100 kHz and 14.8 ns, respectively. The beam quality factor is Mx2=1.45 and My2=1.34. According to our knowledge, this is the maximum output power with a pulse width of ten-nanoseconds level and repetition rate of one-hundred-kilohertz level by an A-O Q-switch at the wavelength of 1342 nm. [ABSTRACT FROM AUTHOR]

This paper explores the production of linearly polarized laser output in a diode-pumped Yb:YAG laser at various pumping coupling ratios. To investigate the polarization mode locking mechanism with various pump coupling ratios, variations in beat frequency and beam profiles associated with different polarization states were analyzed. The study confirmed that the emission of linearly polarized laser with different mode-matching coefficients results from the coherent superposition of two orthogonally polarized eigenmodes within the resonator. Importantly, the experiment showed that adjusting pump coupling ratios allows achieving linearly polarized emission. Notably, within a specific range, linearly polarized laser emission remains unaffected by pumping coupling ratios. Beam quality factor measurements reveal that the beam quality of linearly polarized laser, generated through coherent superposition, surpasses that of partially polarized laser, with all beam quality factors being less than 1.5. [ABSTRACT FROM AUTHOR]

In optomechanics, the interaction between light and matter is enhanced by engineering cavities where the electromagnetic field and the mechanical displacement are confined simultaneously within the same volume. This leads to a wide range of interesting phenomena, such as optomechanically induced transparency and the cooling of macroscopic objects to their lowest possible motion state. In this manuscript, the focus is on designed optomechanical cavities exploiting heterostructures in air‐slot photonic‐crystal waveguides, incorporating different hole shapes and dimensions to engineer and control their optomechanical properties. The aim is to maximize the optical quality factor of the optical cavity, while ensuring optical mode volumes below the diffraction limit. These optimized optical modes interact with in‐plane motional degrees of freedom of the structures achieving high optomechanical coupling rates, thus opening up the possibility of mechanical amplification, nonlinear dynamics and chaos through the optomechanical back‐action. [ABSTRACT FROM AUTHOR]

Chiral metasurfaces have attracted considerable attention because of their immense potential for diverse applications requiring chiral light-matter interactions. Recently, boosted by a mechanism based on the concept of bound states in the continuum (BICs), high Q factor chiroptical resonances have been exhibited by breaking the inversion symmetries of planar metasurfaces. However, the optical chirality of these chiral metasurfaces is generally intolerable with respect to the structural geometries, especially the geometric asymmetry. Here, we present a novel chiral quasi-BIC with strong optical chirality in an all-dielectric metasurface. By simultaneously breaking the in-plane C 2 rotational and mirror symmetries, the chiral metasurface shows enhanced chiroptical resonances with near-unity CD (∼0.996) and high Q factors (∼2274) at terahertz frequencies. Further analyses based on numerical simulations reveal that the CD of the chiroptical resonance depicts exceptional remarkable tolerableness to the geometry asymmetry δ when δ are present in a broad range, while the corresponding Q factor is modulated accordingly. The results may develop a novel approach to manipulating the advanced optical chirality for potential applications requiring strong CD with enhanced light-matter interactions. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to particle detection using an active microresonator operating in the transparency regime. Simulations demonstrate that when particles interact with the microresonator surface, they induce optical losses. To compensate for these losses, the optical gain is amplified to restore the transparency regime. Simulation results show a linear relationship between nanoparticle concentration and the pump power required to compensate for optical losses. By the use of microresonator with a very high quality factor, this approach offers an accurate and sensitive method for detecting nanoparticles, without the need for complex equipment. [ABSTRACT FROM AUTHOR]

The vibrations in functionally graded porous Cu-Si microcantilever beams are investigated based on physical neutral plane theory, modified coupled stress theory, and scale distribution theory (MCST&SDT). Porous microcantilever beams define four pore distributions. Considering the physical neutral plane theory, the material properties of the beams are computed through four different power-law distributions. The material properties of microcantilever beams are corrected by scale effects based on modified coupled stress theory. Considering the fluid driving force, the amplitude-frequency response spectra and resonant frequencies of the porous microcantilever beam in three different fluids are obtained based on the Euler–Bernoulli beam theory. The quality factors of porous microcantilever beams in three different fluids are derived by estimating the equation. The computational analysis shows that the presence of pores in microcantilever beams leads to a decrease in Young's modulus. Different pore distributions affect the material properties to different degrees. The gain effect of the scale effect is weakened, but the one-dimensional temperature field and amplitude-frequency response spectra show an increasing trend. The quality factor is decreased by porosity, and the degree of influence of porosity increases as the beam thickness increases. The gradient factor n has a greater effect on the resonant frequency. The effect of porosity on the resonant frequency is negatively correlated when the gradient factor is small ( n < 1 ) but positively correlated when the gradient factor is large ( n > 1 ). [ABSTRACT FROM AUTHOR]

In this article, the impact of the excited electromagnetic surface modes in a comprehensive investigation of the formation of laser‐induced periodic surface structures (LIPSS) is analyzed. It is demonstrated that the electromagnetic origin of low spatial‐frequency LIPSS (LSFL) is the frequency detuning between propagating and localized modes due to their coupling/hybridization. The influence of the pattern profile, inhomogeneity, and material type on the coupling strength, electric‐field spatial distribution, and associated near‐field scattering are highlighted. Exploiting the potential of the approach, evidence of a universal manifestation of LSFLs is provided irrespective of the material and the authors are able to predict and validate the experimentally‐proven lower limit of LSFL periodicity (i.e., λL/2, where λL stands for the laser wavelength). Furthermore, the analysis of the electromagnetic modes predicts that the periodicity of LSFL is practically unaffected by the laser fluence, while a suppression of LSFL at high excitation levels or large number of pulses is also predicted. It is also shown that plasmonic‐active materials are not necessary for LSFL formation perpendicular to polarization. Toward these directions, an important generic metric, namely the resonance quality factor, is additionally inserted. The approach can, thus, serve as a guide for controlling laser‐induced surface topography. [ABSTRACT FROM AUTHOR]

Thin‐film lithium niobate (TFLN) enables extremely high‐efficiency second‐order nonlinear optical effects due to large nonlinear coefficient d33 and strong optical field confinement. Here, a pulley‐waveguide‐coupled microring resonator with an intrinsic quality factor above 9.4 × 105 on the reverse‐polarized double‐layer X‐cut TFLN is designed and fabricated. In such a TFLN resonator without fine domain structures, second harmonic generation with a normalized conversion efficiency of 440,000% W−1 with weak pump power, approaching that in periodically poled lithium niobate (PPLN) microring resonators, and an absolute conversion efficiency of 30% is realized with a sub‐milliwatt continuous pump. This work reduces the dependence of high‐efficiency nonlinear frequency conversion on PPLN microcavities that are difficult to prepare. [ABSTRACT FROM AUTHOR]

Creatinine-based estimated glomerular filtration rate (eGFR) is imprecise at individual level, due to non-GFR-related serum creatinine determinants, including atypical muscle mass. Cystatin C has the advantage of being independent of muscle mass, a feature that led to the development of race- and sex-free equations. Yet, cystatin C–based equations do not perform better than creatinine-based equations for estimating GFR unless both variables are included together. The new race-free Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation had slight opposite biases between Black and non-Black subjects in the USA, but has poorer performance than that the previous version in European populations. The European Kidney Function Consortium (EKFC) equation developed in 2021 can be used in both children and adults, is more accurate in young and old adults, and is applicable to non-white European populations, by rescaling the Q factor, i.e. population median creatinine, in a potentially universal way. A sex- and race-free cystatin C–based EKFC, with the same mathematical design, has also be defined. New developments in the field of GFR estimation would be standardization of cystatin C assays, development of creatinine-based eGFR equations that incorporate muscle mass data, implementation of new endogenous biomarkers and the use of artificial intelligence. Standardization of different GFR measurement methods would also be a future challenge, as well as new technologies for measuring GFR. Future research is also needed into discrepancies between cystatin C and creatinine, which is associated with high risk of adverse events: we need to standardize the definition of discrepancy and understand its determinants. [ABSTRACT FROM AUTHOR]

In order to adjust the structure of inefficient Pinus massoniana(P)forest and explore the dynamic changes for dissolved organic carbon(DOC)during the mixed decomposition process of P. massoniana and native broad-leaved tree species. Our research focuses on the leaf litter of P. massoniana, Cinnamomum camphora(C)and Toona sinensis(T), and combine them into the 15 treatments(3 single tree treatments + 12 mixed treatments)according to different tree species combinations and mass proportions, and then conducted field decomposition experiments to further explore the optimal tree species combination and the proportion of mixed planting for DOC release. The results were as follows:(1)DOC content of Pinus massoniana and most of mixed treatments(except for PT64)significantly increased during the early stages of decomposition(0-6 months), leading to carbon enrichment. The DOC content of leaf litter decreased with the extension of decomposition time, and also exhibited carbon enrichment in small degree during the middle to late stages of decomposition(12-18 months)or the late stages of decomposition(18-24 months). Mixed leaf litter showed that the higher the proportion of broad-leaved, the lower the DOC content in the later stage. (2)The antagonistic effect of DOC release rate in the early stage of decomposition(0-6 months)was strong(58. 33%), and only 8. 33%(1/12)of mixed treatments showed the synergistic effect. Its synergistic effect gradually strengthened(91. 67%)after 6-18 months, but the synergistic effect of leaf litter(66. 67%)during the late stage of decomposition weakened(18-24 months). Among all mixed treatments, PT64 exhibited synergistic effects throughout the entire decomposition stage, followed by PT73, PCT622 and PCT613(3/4). (3)Partial least-squares(PLS)regression showed that N content, P content, lignin content, condensed tannin content, C/N, C/P, lignin/N, and lignin/P were important quality factors affecting the release of DOC from litter in this study area. Overall, the DOC release from mixed Pinus massoniana and broad-leaved leaf litter is affected by tree species, mixed proportion and decomposition time. Compared to other mixed treatments, the proportion of broad-leaved greater is than or equal to 30. 00% and the mixed leaf litter treatments including Toona sinensis(PT64, PT73, PCT622 and PCT613)show strong synergistic effects for DOC release. [ABSTRACT FROM AUTHOR]

Transformer oil plays the role of heat dissipation and insulation in power transformers, and its electrical and thermal characteristics are directly related to the stable operation of the transformer. At the same time, it is important to master the electric–thermal characteristics of transformer oil for transformer state evaluation, latent fault prediction, and maintenance planning. Based on this, the gas production rule and electrical characteristics of transformer oil under accelerated aging are studied in this paper. First, the experimental platform for power transformer aging is established to accelerate the aging of power transformers. Second, the accelerated aging transformer oil is taken as the research object, and the power frequency, DC, lightning, and gas chromatography are measured and analyzed. Finally, a transformer oil aging evaluation model is established, which takes into account four factors: carbon and oxygen gas factors in transformers, life loss factors calculated by hotspot temperature, hydrocarbon gas factors dissolved in transformer oil, and oil quality factors, and conducts aging evaluation. The conclusion shows that the T parameter proposed in this paper can effectively evaluate the quality of transformer oil. When T is less than or equal to 0.6, there is no aging of the oil. When T is greater than 0.6 and less than 1, the transformer oil has been aging, but it is not manifested. Those are parameters whose chromatography and breakdown voltage are not far beyond the IEEE standard. When T = 1, the aging of oil with significant changes in gas content and breakdown voltage can be observed. When T is greater than 1, the oil has undergone serious aging. [ABSTRACT FROM AUTHOR]

Traditional logic circuit emits energy into the environment due to information loss, and it is referred to be irreversible logic circuits. Reversible logic circuit is capable of diminishing power loss, quantum cost, and garbage output. Many academics have recently embraced reversible logic-based circuits exploiting all-optical technology to conduct their research. In this article, all-optical reversible adder and subtractor have been implemented using microring resonator-based Naveen Raymond reversible logic gate, for the first time to our knowledge. MATLAB serves as the tool for design and analysis of the proposed architecture at almost 260 Gbps operational speed. The ultrafast response times and compact design of the microring resonator-based circuits make them especially useful for digital signal processing and communication systems. Some performance reflecting factors such as "quality factor", "photon cavity lifetime", "extinction ratio", "contrast ratio", "amplitude modulation", "on-off ratio", and "relative eye opening" are explored and analyzed. Optimized design parameters have been selected in order to build the model practically. [ABSTRACT FROM AUTHOR]

Early identification of Mycobacterium strains that cause TB (Tuberculosis) is crucial in preventing tuberculosis illness. Conventional medical diagnostics, such as PPD (tuberculin skin tests) tests and antibody-assisted tests, have low sensitivity, extensive processing times, and complex post-test procedures. These problems minimize its potential and drive innovation in tuberculosis diagnosis. Biosensors have simplified the identification of illnesses by reducing the time between sample and results. This paper proposes a circular ring-shaped refractive index sensor for the identification of the four different types of mycobacterium tuberculosis cells. This sensor has achieved the highest sensitivity of 1500 nm/RIU for all four types of tb cells by analyzing the different parameters like substrate height, resonator height, radius of the circle, length of the substrate, and width of the circle resonator. It covers the wavelength range of 2000 nm to 2050 nm. The highest value of the quality factor has been observed is 40,280 for TBC2 (Tuberculosis cell 2, specific type of tuberculosis) and the highest value of the figure of merit has been observed is 30,000 for TBC2 compared to normal cells. The best response for the DL (Detection limit) has been observed at 0.000005 for TBC2. [ABSTRACT FROM AUTHOR]

This paper presents a graphene–gold-metasurface sensor designed for rapid and precise detection of heavy metals, particularly Cu2+ and Mg2+ ions, in water samples. By employing COMSOL simulations, the sensor's performance across various cases was comprehensively analyzed. The sensor demonstrates an optimized sensitivity of 1140 GHz/RIU for Cu2+ detection and 1149 GHz/RIU for Mg2+ detection. Furthermore, this sensor achieves minimum figure of merit (FOM) of 2.781 RIU−1 and 2.855 RIU−1 for Cu2+and Mg2+ detection, respectively, showcasing its superior performance in sensing these metal ions. Also the highest quality factors (Q factors) of 11.244 for Cu2+ detection and Q factor 11.247 for Mg2+ detection are attained. The proposed sensor structure additionally demonstrates very low detection limits- which is 0.466 for Cu2+ and 0.485 for Mg2+ detection-and this implies it can detect trace amounts without any difficulty. The excellent promising features of this sensor position it as a self directed candidate for detection of Cu2+ and Mg2+ ions with high accuracy and sensitivity. These solid applications act as the gateway to the monitoring of environmental cleanliness among other applications. Additionally,the proposed sensor can also be used as a 2-bit encoder. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of a temperature sensor that utilizes an optical filter consisting of an elliptical-shaped photonic crystal ring resonator (E-PhCRR) in a two-dimensional configuration. The basic structure comprises silicon (Si) rods immersed in the air (disconnected structure) arranged in a triangular lattice. The newly designed structure's photonic band gap (PBG) was calculated using the plane wave expansion (PWE) method, and the temperature sensor was modeled and studied using the finite difference time domain (FDTD). The temperature change causes a redshift in the resonance wavelength due to the subsequent change in refractive index. The temperature was systematically adjusted within the range of 0 °C to 50 °C, leading to a discernible change in the resonant wavelength by 5.2 nm, shifting it from 1682.59 nm to 1687.79 nm. The elliptical shape of the photonic crystal ring resonator provided us with significant flexibility to attain improved outcomes. Specifically, we achieved a quality factor of 316200, a temperature sensitivity of 103.92 pm/°C, and a refractive index sensitivity of 443 nm/RIU. Furthermore, we were able to acquire a detection limit of 5.12 × 10 - 9 RIU while maintaining a compact size of 116.5 μ m 2 . [ABSTRACT FROM AUTHOR]

We propose a Dense Wavelength Division Multiplexing (DWDM) Demultiplexer for L band (1565–1635 nm) applications. The design comprises a Y-shaped branch, a circular ring cavity (CRC), a bus waveguide, and a drop waveguide. To simplify the fabrication process, a CRC cavity is used instead of a regular large ring resonator in the design. The diameter of the CRC cavity is 820 nm. Coupled mode theory is used to examine the behaviour of the proposed demultiplexer. Proposed design achieves a narrow resonant wavelength of 12.5 GHz with a 0.1 nm spectral linewidth, a high-quality factor of 15,789, and minimal cross-talk of − 85 dB between adjacent channels. The results confirm that there is a transmission peak at one of the output port, with simultaneous drop of transmission power i.e. zero, at other output port. Additionally, the results convey that the reflection is zero at the peak resonant wavelength for all channels. Further, the proposed design offers a fabrication tolerance of ± 1 nm for air hole and CRC radii at which the resonant wavelength and transmission would not be effected. [ABSTRACT FROM AUTHOR]

Previous research has demonstrated that interpersonal dynamics are fractal, and that conflict is a key control parameter that drives fractal complexity. The present study aimed to extend this line of research to examine the putative fractal structure of conflict dynamics over time, and the role that this self-organizing fractal structure may play in the resilience of romantic relationships. An experience sampling methodology was used to assess levels of conflict, satisfaction, and commitment in the dating relationships of undergraduate students, three times per day for 30 days. Hypothesis 1 was supported, with conflict ratings over time generally conforming to an inverse power-law distribution (IPL) distribution. Hypothesis 2 was supported as well, with better IPL fits measured as variance accounted for (R2), predicting higher levels of satisfaction and commitment over the 30 days. Hypothesis 3 showed mixed support, with moderate network linkages (i.e., soft assembly) between conflict and satisfaction and commitment predicting higher IPL fits (the linkage of satisfaction and commitment did not predict IPL fit as predicted). Hypothesis 4 predicted that IPL fit would interact with mean conflict, buffering the impacts of conflict on mean satisfaction and commitment across the 30 days. This hypothesis was not supported; however, several statistical factors may have obscured the buffering effects of higher IPL fit and so results may be inconclusive. These methodological factors, and others, are discussed along with the potential theoretical and practical implications of the current results. [ABSTRACT FROM AUTHOR]

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Recently, a robust steganographic algorithm that achieves errorless robustness against JPEG recompression has been proposed. The method employs a lattice embedding scheme and utilizes the syndrome-trellis code (STC) for practical embedding. However, we have noticed that errorless robust embedding with STC may encounter failures due to modifications on wet coefficients, especially when a high quality factor is used by the compression channel. To solve this problem, we have discovered that using steganographic polar code (SPC) for embedding has better performance in avoiding modifications on wet coefficients. In this paper, we conduct theoretical analysis to prove the better performance of SPC in wet paper embedding. We establish the condition of avoiding modifications on wet coefficients, followed by presenting a recursive calculation method for determining the distribution of columns in the generator matrix of SPC. The findings reveal that SPC can avoid modifications on wet coefficients under a larger number of wet coefficients compared with STC, and therefore we propose a better errorless robust embedding method employing SPC. The experimental results demonstrate that under close security performance, the proposed method achieves a higher success rate compared with embedding with STC. Specifically, when the quality factor of the compressor is 95 and the payload size is 0.4 bpnzac, our method achieves a success rate of 99.85%, surpassing the 91.95% success rate of the embedding with STC. [ABSTRACT FROM AUTHOR]

This paper presents a new biquad filter based on carbon nanotube field-effect transistor (CNFET) technology. Implementing various filter modes (high-pass, low-pass, band-pass, and band-stop) in four operating modes (voltage, current, transconductance, and transresistance) with a unified circuit structure is the fundamental feature of the proposed filter. The proposed universal filter is intended for commercial radio communications in the FM band to reduce power consumption and chip area occupation. The proposed circuit can adjust a wide frequency range and thus cover multiple radio channels with minimum noise and distortion on the signal. The proposed filter in 20 nm technology has been simulated using advanced design system (ADS) software to investigate the effects of high-frequency effects. The minimum power consumption is 360 nW, with a supply voltage of 0.9 V, with the ability to independently adjust the center frequency (22 MHz < f0 < 120 MHz) and filter quality factor (0.6 < Q < 23) and the use of grounded capacitors to absorb parasitic effects are among the advantages of the proposed circuit. The proposed Gm-C circuit has the highest figure of merit (FOM) value of 318.5. Moreover, its resistance to process variations, power supply, and temperature changes demonstrates the appropriate performance of the proposed filter. [ABSTRACT FROM AUTHOR]

Silicon photonic waveguide resonators, such as microring resonators, photonic crystal waveguide cavities, and Fabry–Perot resonators based on the distributed Bragg reflectors, are key device components for silicon-based photonic integrated circuits (Si-PIC). For the Si-PIC with high integration density, the device footprints of the conventional photonic waveguide resonators need to be more compact. Inverse design, which is operated by the design expectation and different from the conventional design methods, has been investigated for reducing the photonic device components nowadays. In this paper, we inversely designed the silicon photonic waveguide reflectors for two target wavelengths: one is 1310 nm and the other is 1550 nm. The silicon photonic waveguide reflectors have reflectance of 0.99993 and 0.9955 for the wavelength of 1310 nm and 1550 nm each with 5-μm-long reflectors. Also, we theoretically investigated Fabry–Perot resonators based on the inversely designed photonic waveguide reflectors. Q factors of the Fabry–Perot resonators have been calculated to be 1.3 × 105 for the wavelength of 1310 nm and 2583 for the wavelength of 1550 nm. We have expected that the inversely designed photonic waveguide reflectors and their applications for the Fabry–Perot resonators can be utilized for compact passive/active device components such as wavelength filters, modulators, and external cavity lasers. [ABSTRACT FROM AUTHOR]

Leveraging the rapid carrier recovery times and minimal polarization sensitivity of carrier-reservoir semiconductor optical amplifiers (CR-SOAs), this study embeds them in a Mach–Zehnder interferometer (MZI) setup to emulate a 2x1 multiplexer (MUX) operating at 120 Gb/s. The focus is on incorporating AND logic gate functionalities into the CR-SOAs-based MZI structure to facilitate high-quality multiplexing. The proposed methodology utilizes the intrinsic gain and phase modulation capabilities of CR-SOAs-based MZI to effectively manipulate data streams. This innovative approach capitalizes on the unique properties of CR-SOAs, such as fast response times and low polarization sensitivity, to achieve optimal signal transmission quality and efficient multiplexing. To assess MUX performance, a quality factor metric is introduced as a comprehensive measure of signal integrity. Through exhaustive simulations and meticulous analysis, the study demonstrates the feasibility of achieving the desired data rate while maintaining superior signal transmission quality. The results underscore the efficacy of CR-SOAs-based MZI as versatile modules for high-speed multiplexing applications, offering unparalleled performance and efficiency. This research represents a significant advancement in understanding optical communication systems and provides valuable insights for optimizing signal quality and mitigating interference in practical real-world scenarios. [ABSTRACT FROM AUTHOR]

This paper presents a lumped scalable model for spiral inductors in a radio frequency (RF) gallium nitride (GaN) technology on silicon substrate. The model has been developed by exploiting electromagnetic (EM) simulations of geometrically scaled spiral inductors. To this aim, the technology substrate, i.e., the metal back-end-of-line along with dielectric and semiconductor layers of the adopted GaN process, has been validated by means of experimental data and then used to define the EM simulator set-up for the spiral inductors. The proposed model adopts a simple π-topology with only seven lumped components and predicts inductor performance in terms of inductance, quality factor (Q-factor) and self-resonance frequency (SRF) for a large range of geometrical parameters of the spiral (i.e., number of turns, metal width, inner diameter). [ABSTRACT FROM AUTHOR]