Amplifier Applications Research Articles

Application of Active Components such as DC Generators and Operational Amplifiers in Mechanical Design

DC generators and operational amplifiers have become increasingly important as the need for automation and precise control in mechanical engineering continues to grow. Since their invention in the 19th century, DC generators have played an important role in power systems, especially in applications that require a stable DC power supply. Meanwhile, since the 1960s, operational amplifiers have played an important role in analog circuits, and their applications cover a wide range of fields such as audio processing, signal conditioning, data acquisition and control systems. This paper explores the multiple applications of DC motors and operational amplifiers in mechanical systems and their integration through a literature review approach. It is found that these components not only improve the efficiency and performance of mechanical systems, but also provide higher control accuracy in areas such as robotics and industrial automation. In addition, with the continuous advancement of technology, the combination of the two is expected to realize innovations and breakthroughs in more fields. The research in this paper provides an important reference for the future innovation and development of mechanical engineering

Applications of Op-Amp in Automatic Circuit Design

Operational amplifiers (op-amps) are widely used in automatic circuits. It can amplify, filter, sum, integrate and differentiate the voltage, current and power, and it is one of the indispensable key components in modern electronic technology. The paper, through a method of literature review, explores the working principle and usage of operational amplifiers. Initially, the paper introduces the basic concepts and principles of operational amplifiers, laying a theoretical foundation for subsequent analysis. Then, it meticulously analyzes typical applications of operational amplifiers in analog circuit design, including basic amplification circuits, filters, and signal processing circuits. The paper further explores the pivotal role of operational amplifiers in digital circuits, with a focus on the design of digital-to-analog and analog-to-digital conversion circuits. In the section on automatic control circuit design, the paper discusses feedback control systems, the design of PID controllers, and stability analysis. Finally, the paper looks forward to innovative applications of operational amplifiers in modern circuit design, such as power management, high-speed signal amplification, and low-power design. This research aims to provide practical design ideas and references for engineering designers to enhance the automation and intelligence of circuit design.

Comprehensive analysis of the principle and extensive applications of operational amplifiers in modern electronic systems

Comprehensive analysis of the principle and extensive applications of operational amplifiers in modern electronic systems

Theoretical and Experimental Study of Resistive Thin Film for Application in Resistive Wall Amplifiers

Theoretical and Experimental Study of Resistive Thin Film for Application in Resistive Wall Amplifiers

Ultracompact isolated multilayer broadside-coupled balun with arbitrary isolation bandwidth

Abstract An isolated low-profile multilayer all-ports-matched broadside-coupled balun (BCB) with arbitrary isolation bandwidth is presented. Analytical relations are derived and provided for the isolation circuit (IC) design in terms of electrical and physical parameters. Accordingly, instructions are given on obtaining optimum bandwidth and isolation responses for the IC. Design procedure for the BCB is presented together with a case study for power amplifier application. The BCB is validated theoretically, analytically, and experimentally, and results are in good agreement. The fabricated balun has insertion loss of 0.27 dB, input and output return losses of 19 dB, isolation of 20 dB at fc, and phase and magnitude imbalance better than 2° and 0.2 dB across the Bandwidth (BW), respectively. The realized isolated balun has dimensions of 0.06λg × 0.03λg.

Synthesis and characterization of erbium silica glass and glass-ceramics for potential low-emissivity coating applications

Silica glasses co-doped with varying concentrations of Er3+ (0.8, 1.5, 4, and 8 mol %) were fabricated employing the sol-gel technique. The effects of erbium concentration were evaluated through several characterization techniques, including X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV–visible transmission spectroscopy, and photoluminescence analysis. The incorporation of erbium ions significantly altered the structural, optical, and photoluminescence properties of the doped glasses. XRD analysis revealed the presence of SiO2 in both tetragonal and hexagonal forms, along with Er2SiO5 crystalline phases. SEM images showed irregular rod-shaped structures with agglomeration and micro-flake cubic shapes. FTIR spectroscopy provided insights into the structural characteristics of the materials. Notably, the optical band gap energy of the glassy films increased, accompanied by fluctuating Urbach energy and a slight reduction in the refractive index, attributed to structural changes within the glass network. Photoluminescence spectra indicated strong emissions at 523 and 543 nm, corresponding to the transitions 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2, respectively. Additionally, a notable near-infrared emission at 1532 nm was observed, linked to the transition 4I13/2 → 4I15/2. The color coordinates of the produced glasses were found to be near the green or yellow regions, suggesting potential applications in optical amplifiers, lasers, and low-emissivity coatings.

Exploration of physical, structural, thermal, and optical properties of alkali zinc boro tellurite glasses doped with europium trioxide

In this present work we have studied the physical, structural, thermal, and optical properties of a new set of alkali zinc boro tellurite glasses doped europium trioxide prepared using the melt-quenching method. X-ray diffraction technique (XRD) and SEM were used to determine the non-crystalline property and microstructure property of the prepared samples. By using MAS-NMR spectroscopy and FTIR spectroscopy, the structural changes in the glasses were revealed. The physical properties were described by considering the densities of glass samples and hence molar volume, polaron radius, and oxygen packing density were measured. Thermal stability of glasses was perceived by performing DSC analysis and values ranges from 145 to 190 °C. Using UV–visible absorption spectra, it was possible to calculate the optical properties. The highest refractive index is found as 2.275 for glass AZBTE0 and the lowest is 2.241 for AZBTE5 glass. The ionic behaviour of the glasses was determined by electronegativity and values lie in the range of 1.51 to 1.688. The outcomes of the physical, thermal, and optical characteristics of glasses are intended for potential uses in optical switching and Europium doped fibre amplifier applications.

Properties of Thin Film Composites of rGO–SnO2 and Modeling of Ultraviolet Laser‐Induced Conductivity Decay

AbstractReduced graphene oxide (rGO) and tin dioxide (SnO2) form composites in a wide range of SnO2/rGO proportions, which are deposited as thin films on borosilicate glass and silica substrates. The rGO proportion affects the SnO2 optical properties and the sample surface, as observed by optical transmittance and confocal and scanning electron microscopies images, mainly for high proportion of rGO. For low proportion, the presence of small surface islands may contribute to optical confinement. The evaluated bandgap is basically from the SnO2 matrix unless the presence of rGO affects the optical absorption edge. Monochromatic ultraviolet light from a He–Cd laser (325 nm) irradiating on the composite film increases the conductivity, giving rise to the phenomenon of persistent photoconductivity (PPC), even very close to room temperature. Modeling by considering mainly the SnO2/rGO interface barrier for electron transport, yield an interface energy barrier of 250 meV. The strong response to ultraviolet light and the phenomenon of PPC indicates potential application in amplifiers, which could be adjusted by doping with rare‐earth ions, such as Er3+ in the SnO2 matrix.

Non-Hermitian mode management in periodically modulated waveguide amplifiers

We propose an efficient mode management scheme in active nonlinear multimode fibers based on non-Hermitian potentials in the longitudinal direction with an antisymmetric transverse profile. The proposal takes advantage of the nonlinear saturation toward particular mode configurations, which can be tuned by the non-Hermitian potential. We demonstrate flexible control of the beam profile within the parameter space of the applied potential with various possibilities, such as improving the beam quality by condensing photons to the lowest order Hermite mode, exciting higher order modes, or engineering a desired mode profile as a combination of modes. The effect is also analytically predicted using a mode-expansion approach, showing good agreement with the full model calculations based on the complex Ginzburg–Landau equation. This study was performed for 1D planar guiding structures, yet the results can be extended to 2D fibers and could be very useful in applications of fiber amplifiers and lasers.

Application Of High Bandwidth Two-Stage Amplifier in Communication System

With the rapid development of communication technology, the application of high-bandwidth amplifiers in communication systems becomes more and more important. Currently researchers have applied high bandwidth two-stage amplifier technology in many fields such as cloud computing and data centers, video and audio transmission, virtual reality and augmented reality, Internet of Things, financial transactions, etc., and in this paper we will focus on its application in communication systems. In this paper, the basic principle and structure of two-stage amplifier are firstly described, and then the key theories of high-bandwidth technology including its concept, importance, principle and core technology of high-bandwidth design technology as well as stability analysis and design are elaborated, and the applications of high-bandwidth two-stage amplifiers in wireless communication system, fiber optic communication system, data center network, and satellite communication are enumerated. In summary, high-bandwidth two-stage amplifiers play a key role in a variety of communication systems, helping to provide stable, high-speed, long-range signal transmission. Through the research of this thesis, it is expected to provide new references and ideas for the research and development in the field of communication technology, and to promote the progress and innovation of communication system.

Supermode lasing and light amplification in multicore bismuth-doped fiber.

Multicore fibers are promising structures with specific light propagation properties, which can be managed to benefit several applications in optical communications, fiber lasers and amplifiers, high-resolution imaging, and fiber-based sensors. The current use of multicore fibers in laser technology is mainly focused on in-phase coherent beam combining in far-field regions (out-cavity) using bulk optical elements. However, this approach is challenging in terms of the power scalability of all-fiber lasers (intra-cavity), particularly with using low-gain media, where it is needed to provide mode-coupling (supermode propagation) stability along relatively long lengths. Here, we report a conceptual design and fabrication of a multicore bismuth-doped fiber that is capable of achieving light amplification and stable lasing in the E-telecom band inside the cavity using the supermode selection approach. By analysis of experimental and simulation data, it was found that the employment of the proposed design of a Bi-doped fiber provides a considerable advantage over the single-core fiber in terms of laser performance (output power, slope efficiency) in the cladding-pumped configuration. These results open up new opportunities for further advancement of the optical fiber technology towards efficient bismuth-doped fiber-integrated amplifiers and lasers for the O+E+S+C+L+U-telecom bands, which may find important applications, especially for the development of next-generation multiband optical transmission systems.

Recent Advances and Applications of Semiconductor Optical Amplifiers

This paper describes the recent advances in device designs and optical transmission applications of semiconductor optical amplifiers (SOA). The device advances described are quantum-dot-based SOA and photonic-integrated circuits using SOA. The use of nonlinear properties of SOAs in high-speed optical transmission is discussed.

Kinetostatic Modeling of an Asymmetrical Double-Stepped Beam for Displacement Amplification

Abstract A kinetostatic model of an asymmetrical double-stepped beam under axial loading is developed. The beam is composed of two thick segments and three thin segments where a thick segment is between two thin segments, and the longitudinal axis of the thick segment is not colinear with that of the thin segment. The kinetostatic model based on the beam constraint model (BCM) is capable of predicting accurate bending and near-buckling behaviors of the beam. A virtual rigid link neighboring the noncolinear segments is introduced in the BCM to broaden the applicability of the BCM. An analytical formula to represent the critical load of a symmetrical double-stepped beam under axial loading is derived and the value calculated by the formula agrees with the limit load of the asymmetrical double-stepped beam within the elastic range. The investigated beam has potential applications in displacement amplifiers and robotic grippers.

Exploring the optical properties of the 1.53 μm emission in Er3+-doped glass, anti-glass and ceramic in TeO2 - Ta2O5 – Bi2O3 system

A series of 80TeO2 - 10Ta2O5 – 10Bi2O3 glasses, anti-glasses and ceramics doped with different concentrations of Er₂O₃, ranging from 0.25 % to 2 % mol, were synthesized to explore their structural transformation and optical properties. The maximum solubility of Er₂O₃ was identified at 1.25 % mol, beyond which the glass transitioned from an amorphous to a crystalline structure. The anti-glasses and ceramics obtained from the heat treatment of the parent glasses were also studied to gain insights into their optical properties. This study reveals a direct relationship between Er3+ ions concentration and full width at half maximum (FWHM) of photoluminescence spectra. The increase in Er3+ ions concentration correlates with a rise in FWHM, indicative of spectral broadening. Anti-glass exhibits a higher emission intensity, followed by ceramic and then glass, reflecting their distinct structural properties. Anti-glass doped with 1 % mol Er2O3 shows an FWHM over 130 nm under 578 mW pumping. The lifetime of the excited state 4I13/2 increases with the Er2O3 content in the anti-glass and the ceramic, with a notable decrease at 1 % mol Er2O3 ions for both materials, while in glass, the decrease is observed at 0.5 %. Emission cross-sections decrease with increasing Er3+ ions concentration and power, influenced by factors like thermal effects and saturation. The Judd-Ofelt theory highlights structural differences, with glasses having a more disordered structure and with an increase in the Ω₆ parameter across all materials, implying enhanced electric dipole line strength and spontaneous emission probability with higher Er₂O₃ content. Overall, this comprehensive study provides valuable insights into the optical behavior of Er3+ ions in these materials, essential for applications in laser design and optical amplifiers.

Quantum size luminescence effect in local field enhancement of Ag NP added Er3+ glass system

This research investigates the effect of silver (Ag) addition on the photoluminescence enhancement properties of 20Li2O–5Bi2O3-(74-x)TeO2–1Er2O3-xAg glass samples, aiming to optimize luminescence for applications in optical amplifiers and laser technologies. The enhancement of luminescence properties for both upconversion 4S3/2 → 4I15/2 green band and 4F9/2 → 4I15/2 red peak luminescence observed are analyzed by quantum yield ξ and relative intensity enhancement (I/Io) parameters. The enhancement on green luminescence properties are observed with high ξgreen and I/Iogreen at x < 1 mol% which can be explained within the cavity quantum electrodynamics (CQED) framework due to very low dipolar localized surface plasmon mode volume Veff (∼10–20 × 10−22 m3) allowing stronger quantum size luminescence effect. Meanwhile, the quenching of ξgreen (0.61) at x≥ 1 mol% may indicate the weaker quantum size luminescence effect. An anomalous enhancement on red luminescence properties with high ξred (2.07) and I/Iored (1.79) at x = 1.25 mol% cannot be explained by CQED framework but from phonon-assisted energy transfer (PET) mechanism occurred due to structural changes. The near-field and far-field parameters of AgNP are simulated. Results demonstrated stronger near field electric field distribution enhancement at x = 0.5 mol% and x = 0.75 mol%. This suggests that an optimal AgNP radius exists for promoting the quantum size luminescence effect in our glass samples, falling within the range of 50.00–60.00 nm. Further supporting this conclusion, theoretical calculations using light intensity scattering efficiency (Qsca) revealed the highest values between 50.00 and 70.00 nm of AgNP radius in our glass samples.

Comparative experimental study of different fetch distances, interpolation algorithms, source substrate noise, sampling point counts, and resolution for NF of BDFA

Noise figure (NF) is a key metric for Fiber amplifier (FA), which affects the performance of signal transmission. The main factors affecting the NF are related to the amplified spontaneous emission (ASE) characteristics of the active fiber itself. However, during our study of NF, we found some easily overlooked factors that can have a significant impact on the results, such as the fetch distances and interpolation algorithm for calculating the ASE where the signal wavelength is located. Further, to date, we have also found little relevant research on whether the sampling characteristics of the instrument and the substrate noise contribute to the NF. On the other hand, bismuth-doped fiber amplifiers (BDFA) have developed rapidly in recent years. In this work, we use BDFA as an example, using different fetch distances, interpolation algorithms, substrate noise, and sampling variables (resolution and point counts), to comprehensively compare and analyze the impact caused by NF. The experimental results suggest that the distance between the sampling locations on either side of the signal and the center wavelength must exceed the signal’s bandwidth to obtain the actual NF; Linear interpolation and cubic interpolation are more suitable for calculating the NF; Even using a high power input signal of 0 dBm, the NF is only degraded by about 1.8% compared to the case where the substrate noise is ignored; In addition, the effect of different sampling point counts and resolutions have less influence on the NF. We believe this work provides a reliable reference value for calculating the accuracy of NF and will be useful for practical applications of active-fiber amplifiers.

Effect of annealing on the electrical performance of N-polarity GaN Schottky barrier diodes

A nitrogen-polarity (N-polarity) GaN-based high electron mobility transistor (HEMT) shows great potential for high-frequency solid-state power amplifier applications because its two-dimensional electron gas (2DEG) density and mobility are minimally affected by device scaling. However, the Schottky barrier height (SBH) of N-polarity GaN is low. This leads to a large gate leakage in N-polarity GaN-based HEMTs. In this work, we investigate the effect of annealing on the electrical characteristics of N-polarity GaN-based Schottky barrier diodes (SBDs) with Ni/Au electrodes. Our results show that the annealing time and temperature have a large influence on the electrical properties of N-polarity GaN SBDs. Compared to the N-polarity SBD without annealing, the SBH and rectification ratio at ±5 V of the SBD are increased from 0.51 eV and 30 to 0.77 eV and 7700, respectively, and the ideal factor of the SBD is decreased from 1.66 to 1.54 after an optimized annealing process. Our analysis results suggest that the improvement of the electrical properties of SBDs after annealing is mainly due to the reduction of the interface state density between Schottky contact metals and N-polarity GaN and the increase of barrier height for the electron emission from the trap state at low reverse bias.

Crystal growth, structure, spectral and thermal properties of ScxY1-xCOB single crystals

Yttrium calcium oxyborate (YCOB) crystals are excellent nonlinear optical crystals. To enhance the thermal properties of YCOB crystal, Sc-doped YCOB crystals, denoted as ScxY1-xCa4O(BO3)3 (x = 0.1 and 0.2) were grown using the Czochralski method along the b-direction. Various measurements, including X-ray powder diffraction, rocking curve analysis, inductively coupled plasma-optical emission spectroscopy (ICP-OES), transmission spectroscopy, density measurements, and thermal property assessments, were conducted to evaluate the characteristics of the ScxY1-xCOB crystals. The results indicated that ScxY1-xCOB crystals have an isostructural arrangement like YCOB, with segregation coefficients of approximately 0.2. The full width at half maximum (FWHM) values of the rocking curves of the ScxY1-xCOB (x = 0.1 and 0.2) crystals are 33.9″ and 29.3″, respectively. Furthermore, the specific heat, thermal diffusion coefficients and thermal conductivity of the ScxY1-xCOB crystals were examined in the temperature range of 298–573 K, which were found to be higher than those of pure YCOB. These high-quality ScxY1-xCOB crystals are expected to serve as suitable nonlinear optical crystals media for optical parametric chirped pulse amplification (OPCPA) applications.

Systematic analysis of the principles and application scenarios of Low-Noise Amplifier

As society advances, new ideas and products are increasingly integrated into our daily lives. 5th generation mobile networks tech enables faster, lag-free connectivity, raising performance standards for components like Low-Noise Amplifiers. Summarizing Low-Noise Amplifier tech and applications helps researchers and firms leverage past knowledge and explore innovations. This paper analyzes Low-Noise Amplifier development and application, discussing types, principles, key performance indicators, and circuit structures of basic amplifiers. Five vital Low-Noise Amplifier characteristicsnoise figure, impedance matching, linearity, stability, and gainare examined. The author introduces design and application cases in radio astronomy, navigation systems, and 5th generation mobile networks communications based on Low-Noise Amplifier characteristics and performance requirements. The author concludes that advancing radio frequency tech requires improved Low-Noise Amplifiers, especially for high-frequency signals in 5th generation mobile networks. Promising noise performance enhancements come from technologies like modified high electron mobility transistors on GaAs and InP substrates. Monolithic Microwave Integrated Circuit integration reduces size while maintaining cost-effective performance. Future advancements in these areas could further boost Low-Noise Amplifier performance.

High-efficiency fiber-cladding power stripper based on all-dielectric optical thin films.

Although conventional fiber-cladding power strippers (CPSs) based on the techniques of high-index adhesive or corrosive liquids onto fiber inner cladding have been well developed, they are still facing challenges in special applications such as spaceborne or radiation-environment fiber lasers and amplifiers. In this paper, we propose and fabricate high-efficiency CPSs based on all-dielectric optical thin films. By numerically analyzing the propagation characteristics of cladding light at the thin film interface, we design a high-index T a 2 O 5 CPS and A l 2 O 3 CPS with single- and cascaded-layer films coated onto the fiber inner cladding, respectively. In our experiment, the CPSs are successfully fabricated onto the inner-cladding surface of 10/125 double-clad fiber based on ion-beam-assisted deposition technology. The stripping efficiency for the 976nm residual cladding power was measured up to 99.38%, and the stripping power of the fiber CPS without active cooling can be 24W at least. Such CPS could be advantageous for applications in spaceborne-based fiber lasers or amplifiers (e.g.,gravitational wave detection, spaceborne lidar).