Browse Topic: Amplifiers
Modern communication networks rely on optical signals to transfer vast amounts of data. But just like a weak radio signal, these optical signals need to be amplified to travel long distances without losing information. The most common amplifiers, erbium-doped fiber amplifiers (EDFAs), have served this purpose for decades, enabling longer transmission distances without the need for frequent signal regeneration. However, they operate within a limited spectral bandwidth, restricting the expansion of optical networks.
In an era where technological advancements are rapid and constant, the U.S. Army will need a more agile and efficient approach to modernizing systems on succeeding generations of Army vehicles. Legacy platforms like Abrams, Stryker, and Bradley vehicles use multiple mission computers tied to individual sensors that often required the addition of “boxes” to accommodate new capabilities, which could take years to deploy and drove sustainment costs up due to vendor lock. In addition, this antiquated approach doesn’t leverage data to converge effects across the formation in a multi-domain environment. Centralized, common computing as detailed in GCIA would help solve this problem, potentially linking all major subsystems and providing higher-speed processing to assess large datasets in real time with AI and ML algorithms. By using a common, open architecture computer, the Army will be able to rapidly integrate new capabilities inside one box, versus adding multiple boxes. This pivotal
Automotive electrical and electronics manufacturer MTA attended IAA Transportation for the first time, demonstrating its new range of wireless communication technologies for the truck industry. Earlier this year, the company acquired Calearo Antenne S.p.A, a company with a long history of producing antennas, amplifiers and cables. MTA global sales director Davide Bonelli explained to Truck & Off-Highway Engineering how that acquisition complements its business. “From a more strategic point of view, we see the world of antennas as complementary to what MTA does,” he said. “Often MTA products have an antenna as an interface, so this is one reason why we have done the deal. There are also a lot of synergies from an engineering standpoint. Historically, MTA is a company that uses many mechanical parts - plastics, metals - which we are very strong with so we can share them. And there are also some competences from Calearo Antenne that can be transferred to us.”
Researchers at Chalmers University of Technology have developed an optical amplifier that they expect will revolutionize both space and fiber communication. The new amplifier offers high performance, is compact enough to integrate into a chip just millimeters in size, and crucially, does not generate excess noise.
The ForgeStar® program, from U.K.-based Space Forge, aims to harness the unique environment of space to create ultra-pure materials that cannot be replicated on Earth. The key opportunities lie in producing high-performance semiconductors and super-alloys with fewer defects and superior properties, thanks to the low-gravity and vacuum conditions of space. Space Forge's ForgeStar satellites will be used to produce advanced materials such as alloys, proteins and semiconductors in the ultra-vacuum and microgravity conditions of space. Manufacturing in low Earth orbit (LEO) has huge potential across sectors from medicine to advanced electronics. Two examples - high frequency amplifiers and super alloys - that Space Forge is focused are described in the next two paragraphs.
For years, expertise in terrestrial applications has served as a launchpad for innovation. Companies honed their skills by building the networks that connected us on earth, but now, eyes are turning skyward. By adapting their capabilit ies to the unique demands of non-terrestrial applications, these same players are unlocking new possibilities and rewriting the rules of communication beyond the atmosphere. Here, Dan Rhodes, Director of Business Development at designer and manufacturer of RF-to-mmWave components and subsystems, Filtronic, explores the bridge between terrestrial expertise and non-terrestrial ambitions, highlighting how terrestrial success is becoming the fuel for stellar solutions. Bridging the terrestrial and non-terrestrial worlds is not merely a matter of applying existing technologies to a new canvas. While both environments share fundamental principles of communication and rely on robust components such as transmitters, receivers, filters and amplifiers, the shift
Mechanical transmissions with gears and shafts transmit torque and speed. However, besides transmitting power, the assembly can behave as torsional vibration amplifier for certain frequencies, and the geometry has a major importance in this context. Using the concept of periodic structures, it is possible to obtain frequency bands with high attenuation, called band gaps. In these wide frequency ranges of attenuation, the structure acts as a mechanical filter, avoiding elastic wave propagation and, therefore, vibration modes. The object of this investigation is the computational modeling of torsional vibrations using the spectral element method and the experimental testing of a periodic shaft with gears, designed to filter both the gear mesh frequency and the engine-related frequency. Hence, a real gearbox shaft is modified to have 3-unit cells and to generate the attenuation frequency bands desired for this application. The effect of gear assembly on the periodic shaft behavior due to
Developers of aerospace and defense systems need RF power amplifiers (PAs) to perform much better across both existing and emerging applications such as military 5G and satellite communication. Systems need to meet higher gain targets but not if it comes with any increases in cost and complexity, or size and weight. As systems move to higher-order modulation schemes, they also must deliver adequate linearity and efficiency in an environment that is even more susceptible to distortion than was the case with earlier schemes. Reducing board space is another critical issue that has required challenging peak-to-average power ratio (PAPR) tradeoffs
This AIR provides guidance to the EMI test facility on how to check performance of the following types of EMI test equipment: Current probe Line Impedance Stabilization Network (LISN) Directional coupler Attenuator Cable loss Low noise preamplifier Rod antenna base Passive antennas All performance checks can be performed without software. A computer may be required to generate an electronic or hard copy of data. This is not to say that custom software might not be helpful; just that the procedures documented herein specifically eschew the necessity of automated operation.
Pulse shaping, as it is done today, is an effort to fix fidelity issues caused by the transmitting amplifier and is accomplished by a combination of imperfect methods, most external to the amplifier. This article will explain a new approach that matches input pulse signal shape, minimizing droop, overshoot, ringing, and rise and fall times.
A new composition of germanosili-cate glass created by adding zinc oxide has properties good for lens applications. The new family of zinc germanosilicate glass has a high refractive index comparable to that of pure germania glass. Samples showed high transparency, good ultraviolet-shielding properties, and good glass forming ability, making them suitable for lens applications. Germanosilicate glass is essential in the manufacture of optical amplifiers, waveguides, and solid-state lasers.
Weak optical signals are common in many science and technology applications. However, they are difficult to detect or process due to the incoherent noise that is inherently present in any system. PhD student Benjamin Crockett and colleagues, working under the supervision of Professor José Azaña of the Institut national de la recherche scientifique (INRS), have conceived a technique for the recovery of weak, noise-dominated optical signals. Their research was published in the journal Optica.
Although wireless charging pads already exist for smartphones, they only work if the phone is sitting still. For cars, that would be just as inconvenient as the current practice of plugging them in for an hour or two at charging stations.
Researchers at Chalmers University of Technology have developed an optical amplifier that they expect will revolutionize both space and fiber communication. The new amplifier offers high performance, is compact enough to integrate into a chip just millimeters in size, and crucially, does not generate excess noise.
The US Army Combat Capabilities Development Command Army Research Laboratory (ARL) has been evaluating and designing efficient broadband high-power amplifiers for use in sensors, communications, networking, and electronic warfare (EW). ARL submitted designs of Ka-band low-noise amplifiers (LNAs), power amplifiers (PAs), and transmit/receive (T/R) switches using Qorvo Inc.’s high-performance 0.15-μm gallium nitride (GaN) fabrication process. These amplifiers were fabricated as one- and two-stage designs, as well as integrated T/R modules for bidirectional transceivers as part of a recent ARL Qorvo Prototype Wafer Option (PWO), which yields many different designs from two full 4-inch GaN wafers. This research documents testing and analysis of these designs, as well as lessons learned for improvements to future design efforts.
Phased arrays have been used in radar applications for many decades. Recent trends are driving their adoption into other applications such as Electronic Warfare (EW), satellite systems, and even 5G communications. There are several new component technologies that are driving this migration: multiple transmit/receive (T/R) modules on a chip, higher-performance PCB laminates, and the acceptance of GaN as a power amplifier (PA) semiconductor process.
Erbium (Er) doped phosphate glass exhibits many beneficial properties, which has led to an increased demand in recent years for Er:glass lasers for applications as wide-ranging as laser rangefinding, long-distance communications, dermatology, and laser-induced breakdown spectroscopy (LIBS). Erbium fiber amplifiers enable rapid global communication in the transpacific cable between Hong Kong and Los Angeles, Er:glass laser rangefinders are increasingly used in defense applications and reconnaissance, and Er:glass aesthetic lasers are gaining traction for removing scarring and even treating hair loss caused by androgenetic alopecia.
Communications in space demand the most sensitive receivers possible for maximum reach, while also requiring high-bit-rate operations. A concept for laser beam-based communications using an almost noiseless optical preamplifier in the receiver has been developed. The free-space optical transmission system relies on an optical amplifier that, in principle, does not add any excess noise, in contrast to all other pre-existing optical amplifiers referred to as phase-sensitive amplifiers (PSAs).
This SAE Aerospace Information Report (AIR) covers the design parameters for various methods of humidification applicable to aircraft, the physiological aspects of low humidities, the possible benefits of controlling cabin humidity, the penalties associated with humidification, and the problems which must be solved for practical aircraft humidification systems. The design information is applicable to commercial and military aircraft. The physiological aspects cover all aircraft environmental control applications.
A unique challenge in the development of a deep space optical software-defined radio (SDR) transmitter is the optimization of the extinction ratio (ER). For a Mars to Earth optical link, an ER of greater than 33 dB may be necessary. A high ER, however, can be difficult to achieve at the low Pulse Position Modulation (PPM) orders and narrow slot widths required for high data rates.
Power Amplifiers (PAs) are commonplace in Radio Frequency (RF) systems extensively used in applications consisting of over-the-air wireless communications. Wireless communications is a broad market and PAs fill a wide array of those applications. Due to the broad range of applications, PA design techniques must be chosen carefully for each application-specific scenario.
Shafts used in torque and angular velocity transmission may behave as torsional vibration amplifiers due to resonance followed by unwanted vibrations. Many technologies are applied to attenuate vibration in certain frequency ranges in automotive, aerospace and industrial applications. More recently, using the concept of periodic structures (phononic crystals and metamaterials), it has been shown to be possible to obtain frequency band gaps where elastic waves cannot propagate and, therefore, standing waves cannot build up, thus avoiding resonance. Using a few periodic cells large attenuation can be obtained, so that the structure behaves like a mechanical filter. Investigations in periodic structure dynamics have been developed in recent years aiming at to attenuating specific and wide frequency ranges. The periodic structure can be a combination of different materials, or a unique material varying the geometry periodically. This work explores the possibility of using periodic shaft
This SAE Aerospace Standard (AS) provides design criteria and performance tests for portable, handheld, battery-powered, electronic megaphones used by aircraft crew members to provide information and guidance in the event of an aircraft emergency or other non-routine situation.
The US Army Research Laboratory (ARL) has been working with Raytheon to design efficient, broadband, linear, highpower amplifiers and robust, broadband, low-noise amplifiers for future adaptive, multimodal radar systems. Raytheon has a high-performance, W-band, gallium nitride (GaN) fabrication process and a process design kit (PDK) that ARL used to design low-noise amplifiers, power amplifiers, and other circuits for future radar, communications, and sensor systems. After the first set of ARL and Raytheon designs was submitted for fabrication, test designs of broadband Class A/B power amplifiers were developed. While these designs did not get fabricated in the initial effort, they serve to demonstrate the performance, bandwidth, and capability of this GaN process and could potentially be fabricated in the future.
RF Power Amplifiers Go Wide and High The increasing demand for higher data rates in telecommunications and higher resolution in industrial systems is pushing the frequency of operation higher for the electronics that support them. Many of these systems operate over a wide frequency spectrum, and further increased bandwidth requirements are a common request for new designs. Across many of these systems there is a push to use one signal chain for all frequency bands. Advancements in semiconductor technology have led to breakthroughs in capability for high-power and wideband amplifiers. An area that was once dominated by traveling wave tubes has begun to cede ground to semiconductor devices, thanks to the gallium nitride (GaN) revolution that is sweeping the industry and enabling MMICs that generate >1 W of power over many decades of bandwidth. As shorter-gate-length gallium arsenide (GaAs) and GaN transistors become available - coupled with improved circuit design techniques - new
Photonic integrated circuits (PIC) may expand the spectral bandwidth of currently available optical sources at lower cost, smaller size, reduced vibration sensitivity, and higher brightness. Office of Naval Research, Arlington, Virginia For applications in manufacturing, remote sensing, medicine, military, and fundamental science, an ideal laser would have high output power and a diffraction-limited beam. The figure-of-merit to describe this property is the brightness, which scales proportional to output power and inverse to the beam quality factor M2. Lasers that are both compact and have high-brightness are challenging to realize. As the size of the laser is reduced, either the output power is decreased or the M2 is increased, primarily due to a combination of thermal effects and high optical intensities. Many applications, such as spectroscopy, infrared countermeasures, free-space communication, and industrial manufacturing, can benefit from a light source emitting at multiple
Using chirped seed amplification with a MEMS VCSEL seed to scale the output power of a ytterbium fiber amplifier. Army Research Laboratory, Adelphi, Maryland One obstacle in the scaling of high-power fiber lasers arises because of nonlinear effects (e.g., stimulated Brillouin scattering [SBS]) due to the large intensity times length product. Efforts to raise the power threshold include: 1 reducing the Brillouin gain by combining materials with positive and negative elasto-optic coefficients or tailoring the acoustic index to avoid guiding the acoustic wave, 2 reducing the effective Brillouin gain by using a seed linewidth much wider than the Brillouin bandwidth, 3 enlarging the Brillouin bandwidth relative to the seed linewidth, 4 lowering the laser intensity by enlarging the fiber core, and 5 minimizing the required active fiber length by pumping at the wavelength of maximum absorption and doping as heavily as possible. Conventional approaches to broadening the seed linewidth reduce
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