Showing papers on "Amplifier published in 2018"
27 Mar 2018
TL;DR: In this paper, quantum dot active layers for lasers and amplifiers on and off Si have been demonstrated, and results for quantum dot based photodetectors and modulators look promising.
Abstract: Direct epitaxial integration of III-V materials on Si offers substantial manufacturing cost and scalability advantages over heterogeneous integration. The challenge is that epitaxial growth introduces high densities of crystalline defects that limit device performance and lifetime. Quantum dot lasers, amplifiers, modulators, and photodetectors epitaxially grown on Si are showing promise for achieving low-cost, scalable integration with silicon photonics. The unique electrical confinement properties of quantum dots provide reduced sensitivity to the crystalline defects that result from III-V/Si growth, while their unique gain dynamics show promise for improved performance and new functionalities relative to their quantum well counterparts in many devices. Clear advantages for using quantum dot active layers for lasers and amplifiers on and off Si have already been demonstrated, and results for quantum dot based photodetectors and modulators look promising. Laser performance on Si is improving rapidly with ...
176 citations
TL;DR: In this paper, a detailed understanding of the device physics at deep-cryogenic temperatures was developed based on a compact model based on MOS11 and PSP, and the accuracy and validity of the compact models were demonstrated by comparing time and frequency-domain simulations of complex circuits, such as a ring oscillator and a low-noise amplifier, with the measurements at 4 K.
Abstract: Cryogenic characterization and modeling of two nanometer bulk CMOS technologies (0.16- $\mu \text{m}$ and 40-nm) are presented in this paper. Several devices from both technologies were extensively characterized at temperatures of 4 K and below. Based on a detailed understanding of the device physics at deep-cryogenic temperatures, a compact model based on MOS11 and PSP was developed. In addition to reproducing the device dc characteristics, the accuracy and validity of the compact models are demonstrated by comparing time- and frequency-domain simulations of complex circuits, such as a ring oscillator and a low-noise amplifier, with the measurements at 4 K.
147 citations
TL;DR: In this article, the authors proposed an implementation of phase-preserving and phase-sensitive directional amplifiers for microwave signals in an electromechanical setup comprising two microwave cavities and two mechanical resonators.
Abstract: Directional amplifiers are an important resource in quantum-information processing, as they protect sensitive quantum systems from excess noise. Here, we propose an implementation of phase-preserving and phase-sensitive directional amplifiers for microwave signals in an electromechanical setup comprising two microwave cavities and two mechanical resonators. We show that both can reach their respective quantum limits on added noise. In the reverse direction, they emit thermal noise stemming from the mechanical resonators; we discuss how this noise can be suppressed, a crucial aspect for technological applications. The isolation bandwidth in both is of the order of the mechanical linewidth divided by the amplitude gain. We derive the bandwidth and gain-bandwidth product for both and find that the phase-sensitive amplifier has an unlimited gain-bandwidth product. Our study represents an important step toward flexible, on-chip integrated nonreciprocal amplifiers of microwave signals.
146 citations
TL;DR: A unified framework for the modeling, analysis, and design of load-independent Class E and Class EF inverters and rectifiers that are able to maintain zero-voltage switching and, hence, high efficiency for a wide load range without requiring tuning or use of a feedback loop.
Abstract: This paper presents a unified framework for the modeling, analysis, and design of load-independent Class E and Class EF inverters and rectifiers. These circuits are able to maintain zero-voltage switching and, hence, high efficiency for a wide load range without requiring tuning or use of a feedback loop, and to simultaneously achieve a constant amplitude ac voltage or current in inversion and a constant dc output voltage or current in rectification. As switching frequencies are gradually stepping into the megahertz (MHz) region with the use of wide-bandgap (WBG) devices such as GaN and SiC, switching loss, implementing fast control loops, and current sensing become a challenge, which load-independent operation is able to address, thus allowing exploitation of the high-frequency capability of WBG devices. The traditional Class E and EF topologies are first presented, and the conditions for load-independent operation are derived mathematically; then, a thorough analytical characterization of the circuit performance is carried out in terms of voltage and current stresses and the power-output capability. From this, design contours and tables are presented to enable the rapid implementation of these converters given particular power and load requirements. Three different design examples are used to showcase the capability of these converters in typical MHz power conversion applications using the design equations and methods presented in this paper. The design examples are chosen toward enabling efficient and high-power-density MHz converters for wireless power transfer (WPT) applications and dc/dc conversion. Specifically, a 150-W 13.56-MHz Class EF inverter for WPT, a 150-W 10-MHz miniature Class E boost converter, and a lightweight wirelessly powered drone using a 20-W 13.56-MHz Class E synchronous rectifier have been designed and are presented here.
142 citations
TL;DR: This work experimentally demonstrates a reconfigurable non-reciprocal device with alternative functions as either a circulator or a directional amplifier via optomechanically induced coherent photon–phonon conversion or gain, which offers exciting opportunities for combining reconfigurability, non-Reciprocity and active properties in single photonic devices, which can be generalized to microwave and acoustic circuits.
Abstract: Non-reciprocal devices, which allow non-reciprocal signal routing, serve as fundamental elements in photonic and microwave circuits and are crucial in both classical and quantum information processing. The radiation-pressure-induced coupling between light and mechanical motion in travelling-wave resonators has been exploited to break the Lorentz reciprocity, enabling non-reciprocal devices without magnetic materials. Here, we experimentally demonstrate a reconfigurable non-reciprocal device with alternative functions as either a circulator or a directional amplifier via optomechanically induced coherent photon-phonon conversion or gain. The demonstrated device exhibits considerable flexibility and offers exciting opportunities for combining reconfigurability, non-reciprocity and active properties in single photonic devices, which can also be generalized to microwave and acoustic circuits.
137 citations
TL;DR: The experimental results demonstrated that the parasitic lasing as well as the transverse amplified spontaneous emission of the homemade 235-mm-diameter Ti:sapphire final amplifier were suppressed successfully via the temporal dual-pulse pumped scheme and the index-matching liquid cladding technique.
Abstract: We report on the laser pulse output of 339 J centered at 800 nm from a chirped-pulse amplification (CPA) Ti:sapphire laser system at the Shanghai Superintense Ultrafast Laser Facility. The experimental results demonstrated that the parasitic lasing as well as the transverse amplified spontaneous emission of the homemade 235-mm-diameter Ti:sapphire final amplifier were suppressed successfully via the temporal dual-pulse pumped scheme and the index-matching liquid cladding technique. The maximum pump-to-signal conversion efficiency of 32.1% was measured for the final amplifier. With a compressor transmission efficiency of 64% and a compressed pulse duration of 21 fs obtained for the sample light at a lower energy level, this laser system could potentially generate a compressed laser pulse with a peak power of 10.3 PW. The experimental results represent significant progress with respect to the CPA laser.
125 citations
TL;DR: System-level measurements prove the linearizability of the designed Doherty amplifier when a modulated signal is applied, and a simplified approach for the initial bandwidth estimation that requires linear simulations only is presented.
Abstract: This paper presents a novel technique for the design of broadband Doherty power amplifiers (DPAs), supported by a simplified approach for the initial bandwidth estimation that requires linear simulations only. The equivalent impedance of the Doherty inverter is determined by the value of the output capacitance of the power device, and the Doherty combiner is designed following this initial choice and using a microstrip network. A GaN-based single-input DPA designed adopting this method exhibits, on a state-of-the-art bandwidth of 87% (1.5–3.8 GHz), a measured output power of around 20 W with 6 dB back-off efficiency between 33% and 55%, with a gain higher than 10 dB. System-level measurements prove the linearizability of the designed Doherty amplifier when a modulated signal is applied.
99 citations
TL;DR: In this paper, the authors proposed a new battery cell voltage equalization approach using multiple-receiver wireless power transfer (WPT) working at megahertz (MHz), which is advantageous in terms of saved weight and space, ease of implementation, and improved safety.
Abstract: This paper proposes a new battery cell voltage equalization approach using multiple-receiver wireless power transfer (WPT) working at megahertz (MHz). Compared with existing multiwinding transformer, the MHz multiple-receiver WPT system is advantageous in terms of saved weight and space, ease of implementation, and improved safety. In this paper, the unique operating principle of the WPT-based equalization is first explained, through which equalization currents are naturally determined by the battery cell voltage distribution. The currents are also analytically derived. This facilitates the discussion on power amplifier (PA) design. Performance analysis is then provided to investigate the influences of system parameters on the efficiency and equalization ability of the proposed WPT-based equalization system, and thus guide following design and implementation. Considering the uncertainty in PA load due to the random cell voltage distribution, a current-model Class $E$ PA is designed that enables approximately constant PA output current. Experimental results show that the proposed multiple-receiver WPT-based battery cell equalization system can achieve high overall system efficiency (above 71%) when equalizing six lithium-ion battery cells under loosely coupling ( $k$ = 0.065). A good match between the experimental and calculation results also validates the correctness of the theoretical discussion.
97 citations
TL;DR: In this paper, a load modulated balanced amplifier for telecom base station applications adopting a novel mode of operation is presented, which adopts prematching for back-off broadband matching.
Abstract: This paper presents the design and characterization of a load modulated balanced amplifier for telecom base station applications adopting a novel mode of operation. The theory of operation is described explaining the main differences compared to Doherty amplifiers, in particular the RF bandwidth advantages and, on the other hand, the intrinsic nonlinear behavior. The specific design strategy that adopts prematching for back-off broadband matching is explained in detail. A prototype, based on 25-W GaN packaged devices, has been fabricated and measured with single tone CW and modulated signal stimulus. For CW conditions, on the 1.7–2.5-GHz band, the peak output power is between 63 and 78 W, with power added efficiency higher than 48%, 43%, and 39% at saturation, 6- and 8-dB output power back-off, respectively. With a modulated signal for Long Term Evolution the amplifier provides an average output power of around 10 W, with efficiency higher than 40%, and can be linearized by adopting a low complexity predistorter. If compared to previously published power amplifiers targeting similar power and bandwidth, the measurement shows very good performance, demonstrating the potential of this novel technique in the field of efficiency enhanced transmitters.
96 citations
10 Jun 2018
TL;DR: A high-isolation fundamental mixer is used in which the matching networks are designed for good RF/IF isolation to simultaneously achieve high conversion gain and feasible module packaging to improve the signal-to-noise-and-distortion-ratio (SNDR) characteristics.
Abstract: This paper presents a 300-GHz transceiver based on 80-nm InP-HEMT technology. To improve the signal-to-noise-and-distortion-ratio (SNDR) characteristics, a high-isolation fundamental mixer is used in which the matching networks are designed for good RF/IF isolation to simultaneously achieve high conversion gain and feasible module packaging. The measured conversion gain of the fabricated mixer module is $-\mathbf{15}\pm \mathbf{2\ dB}$ , where the LO frequency, IF, and RF are 270, 2–32, and 272–302 GHz. The 300-GHz transceiver consists of the high-isolation mixer, 300-GHz amplifiers, and commercially available frequency multipliers as the LO source. It achieves 100-Gb/s wireless data transmission using 16QAM over a distance of 2.22 m with a 50-dBi antenna. To the best of the authors' knowledge, this is the highest wireless data rate ever achieved using only electronic devices.
88 citations
TL;DR: In this article, a quantum-limited parametric amplifier based on an array of superconducting nonlinear asymmetric inductive elements is proposed to handle large input signals without sacrificing other desirable characteristics.
Abstract: Quantum-limited Josephson parametric amplifiers are a key component in many precision microwave measurement setups, such as for the readout of superconducting qubits in a quantum computer. As qubit setups scale up, these amplifiers must be optimized to handle input signals of ever-larger power. The authors design a quantum-limited parametric amplifier based on an array of superconducting nonlinear asymmetric inductive elements. This ``SNAIL'' is optimized to handle large input signals without sacrificing other desirable characteristics. The method can be extended to improve all forms of parametrically induced mixing in quantum information applications.
TL;DR: This paper presents a CMOS broadband millimeter wave power amplifier (PA) based on magnetically coupled resonator (MCR) matching network, which covers the full Ka-band (26.5 to 40 GHz).
Abstract: This paper presents a CMOS broadband millimeter wave power amplifier (PA) based on magnetically coupled resonator (MCR) matching network. The MCR matching network is analyzed theoretically. Design method for MCR-based broadband PA is proposed. For the PA’s output matching network, the inductance ratio should be equal to the load/source resistance ratio to achieve broadband impedance transformation. And the coupling coefficient ( $k$ ) of the MCR can be determined from the no gain ripple condition. Fabricated in 65-nm CMOS process, the PA chip achieves 32.9% peak power added efficiency, 15.3-dBm saturated output power ( $P_{\mathrm {sat}}$ ), and 12.9-dBm output 1-dB compression point ( $P_{\mathrm {1\,dB}}$ ). The fractional bandwidth of the PA is 63.3% from 21.6 to 41.6 GHz, which covers the full Ka-band (26.5 to 40 GHz).
TL;DR: A mixer-first receiver with enhanced selectivity and high dynamic range is proposed, targeting to remove surface acoustic-wave-filters in mobile phones and cover all frequency bands up to 6 GHz, and the circuit principle is explained and RX performance is analyzed.
Abstract: A mixer-first receiver (RX) with enhanced selectivity and high dynamic range is proposed, targeting to remove surface acoustic-wave-filters in mobile phones and cover all frequency bands up to 6 GHz. Capacitive negative feedback across the baseband (BB) amplifier serves as a blocker bypassing path, while an extra capacitive positive feedback path offers further blocker rejection. This combination of feedback paths synthesizes a complex pole pair at the input of the BB amplifier, which is upconverted to the RF port to obtain steeper RF bandpass filter roll-off and reduced distortion. This paper explains the circuit principle and analyzes RX performance. A prototype chip fabricated in 45-nm partially depleted silicon on insulator (SOI) technology achieves high out-of-band linearity (input-referred third-order intercept point (IIP3) = 39 dBm and input-referred second-order intercept point (IIP2) = 88 dB) combined with sub-3-dB noise figure. Desensitization due to a 0-dBm blocker is only 2.2 dB at 1.4 GHz.
TL;DR: A new structure that can achieve multioctave bandwidth is proposed in this paper together with the design methodology and to verify the validity of the proposed methodology, a multi-octave power amplifier was designed, fabricated, and measured.
Abstract: Total bandwidth of existing wireless communication technologies covers a wide frequency range of over one octave. But most existing power amplifier configurations cannot meet this requirement while at the same time maintaining a high efficiency. Therefore, a new structure that can achieve multioctave bandwidth is proposed in this paper together with the design methodology. The difficulty in realizing a bandwidth larger than one octave lies in the overlapping of fundamental and harmonic frequencies. Regarding this problem, the continuous class-F mode is extended to allow a resistive second harmonic impedance, rather than the pure reactive one. With the relaxed design requirements and overlapping design space of fundamental and second harmonic frequencies, harmonic tuning and fundamental frequency matching networks can be designed separately. More importantly, broadband matching for fundamental frequencies can be implemented simply by considering only three fundamental frequency points using the multiple frequencies matching method. To verify the validity of the proposed methodology, a multioctave power amplifier was designed, fabricated, and measured. Measured results verify a wide bandwidth of 128.5% from 0.5 to 2.3 GHz. Over this frequency range, drain efficiency was larger than 60% with output power greater than 39.2 dBm and large signal gain larger than 11.7 dB.
TL;DR: In this article, a broadband continuous-mode Doherty power amplifier (CM-DPA) is realized taking advantage of the non-infinity output impedances of the peaking stage.
Abstract: In this paper, a broadband continuous-mode Doherty power amplifier (CM-DPA) is realized taking advantage of the noninfinity output impedances of peaking stage Specifically, the carrier PA of the designed DPA operates in a continuous class-J mode when the peaking PA is in the OFF-state, where the output impedance of the peaking PA has some influences on the carrier PA When the peaking transistor is in the OFF-state, the load impedance variation of the carrier transistor versus noninfinity peaking impedance is presented in this contribution The proposed method surmounts the back-off drain efficiency deterioration of DPAs at two side working bands through elaborately processing the noninfinity peaking impedance This paper also presents a method to derive the required OFF-state output impedance of the peaking stage by the carrier PA in a symmetrical broadband DPA A broadband CM-DPA working over 16–27 GHz (bandwidth of 51%) is designed and fabricated for interpreting our theories The simulated load trajectory of the carrier transistor is in line with the design space of continuous class-J mode Under continuous wave excitation, experimental results show the drain efficiencies of 465%–635% at 6-dB output back-off power levels and 56%–753% at peaking power levels The maximum output power of this DPA is 438–452 dBm with a gain of 94–115 dB across the whole working band Furthermore, a 20-MHz LTE modulated signal with a peak-to-average power ratio of 74 dB is also applied to the fabricated CM-DPA at 22 GHz At an average output power of 375 dBm, measurement results show the adjacent channel power ratios of −302 and −501 dBc before and after digital predistortion, respectively
TL;DR: In this paper, a single-stage symmetric Doherty power amplifier (PA) in 45 nm CMOS silicon on insulator at 28 GHz is presented, which achieves a saturated output power of 22.4 dBm, a peak power added efficiency (PAE) of 40%, and a 6 dB back-off PAE of 28%.
Abstract: A single-stage, symmetric Doherty power amplifier (PA) in 45 nm CMOS silicon on insulator at 28 GHz is presented. The PA achieves a saturated output power of 22.4 dBm, a peak power added efficiency (PAE) of 40%, and a 6 dB back-off PAE of 28%. High efficiency is attained due to low combiner losses of 0.5 dB, obtained using a recently developed combiner synthesis technique. A compact modeling approach for parasitic-extracted PA transistors is presented, which considerably reduced simulation time. The PA is based on two-stack power devices and occupies overall chip area of only 0.63 mm2, including pads.
TL;DR: In this paper, the authors proposed a frequency-tunable microwave signal based on a silicon photonic integrated optoelectronic oscillator (OEO), which includes a high-speed phase modulator (PM), a thermally tunable micro-disk resonator (MDR), and a high speed photodetector (PD).
Abstract: Photonic generation of a frequency-tunable microwave signal based on a silicon photonic integrated optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The silicon photonic chip includes a high-speed phase modulator (PM), a thermally tunable micro-disk resonator (MDR), and a high-speed photodetector (PD). When an external light wave is injected into the chip, by a joint use of the PM, the MDR, and the PD, a bandpass microwave photonic filter (MPF) based on phase modulation and phase-modulation to intensity-modulation (PM-IM) conversion is realized. If the output microwave signal from the MPF is fed to the microwave input port of the PM with a sufficiently large gain provided by an electrical amplifier, the MPF becomes an OEO. By controlling the electrical power applied to a micro-heater, the resonance frequency of the MDR is tuned, which leads to the tuning of the MPF, and thus, the OEO oscillation frequency. In the experimental demonstration, two silicon photonic integrated OEOs using two MDRs with different micro-heaters are studied. The first OEO has a high-resistivity metallic micro-heater placed on top of the MDR, and the second OEO has a p-type doped silicon heater in the MDR. The two thermally tunable MDRs are characterized, and the performance of the MPFs based on the two MDRs is evaluated. The use of the two MPFs to implement two OEOs is performed, and their performance is evaluated in terms of frequency tunable range, phase noise, and power consumption.
Patent•
22 Mar 2018
TL;DR: In this paper, a programmable power switching element including a front power transistor, a main switching transistor, and at least one reverse current blocking transistor in series, a gate of each of which is connected to a gate driver, an inductor and a shunt resistor connected in series with the transistors, a charge storage capacitor connected between ground and a junction located between the inductor, and a high-speed NPN transistor.
Abstract: A programmable power (PPSE) switching element including a front power transistor, a main switching transistor, and at least one reverse current blocking transistor in series, a gate of each of which is connected to a gate driver; an inductor and a shunt resistor connected in series with the transistors; a charge storage capacitor connected between ground and a junction located between the inductor and the shunt resistor; a high-speed NPN transistor, a collector of which is connected to the front power transistor and an emitter of which is connected to an output of the main switching transistor via the shunt resistor; a current measurement element in parallel to the shunt resistor; a voltage amplifier; and a high-speed MCU.
TL;DR: This paper presents a low-power and low-noise capacitive-feedback amplifier with a current-reused OTA for ECG recordings that adopts an inverter-based differential input stage for low noise, and a class-AB output stage for large output range and high gm/I efficiency.
Abstract: This paper presents a low-power and low-noise capacitive-feedback amplifier with a current-reused OTA for ECG recordings. To improve the noise-power efficiency, the proposed OTA employs a current-reused architecture, which adopts an inverter-based differential input stage for low noise, and a class-AB output stage for large output range and high g m/ I efficiency. The driving branch of the class-AB output stage is merged into the input stage to realize current reuse and reduce power consumption further. Fabricated in a 0.35-μm CMOS process, the amplifier consumes 160 nA from a 2-V supply, while achieving an input-referred noise of 2.05 μVrms, corresponding to a noise efficiency factor (NEF) of 2.26. The measured common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR) exceed 65 dB and 70 dB, respectively. The total harmonic distortion (THD) is less than 1% with a 15-mVpp input at 20 Hz and the active area is 0.3 mm × 0.6 mm.
TL;DR: In this paper, a planar microstrip meander SWS on a dielectric substrate at 50-70 GHz was studied. And the basic electromagnetic parameters of the SWS were calculated.
Abstract: Slow-wave structure (SWS) is a core part of a traveling-wave-tube (TWT) amplifier. In this letter, the planar microstrip meander SWS on a dielectric substrate at $V$ -band (50–70 GHz) is studied. The basic electromagnetic parameters of the SWS are calculated. The SWS circuits are designed and fabricated, and good transmission characteristics are measured. The SWS developed is characterized by a wide bandwidth and a relatively-large slow-wave factor, and is suitable for a low-voltage TWT with the sheet electron beam.
TL;DR: A 1D chain of bosonic cavities driven in the appropriate manner should exhibit many unique properties suitable for novel realizations of quantum amplifiers and entangled-light generators.
Abstract: A 1D chain of bosonic cavities driven in the appropriate manner should exhibit many unique properties suitable for novel realizations of quantum amplifiers and entangled-light generators.
TL;DR: In this article, the impact of input and output harmonics in the design of high-efficiency power amplifiers (PAs) has been investigated, and four different design cases with different second harmonic source impedances are investigated.
Abstract: This paper presents an in-depth, systematic study of the impact of input and output harmonics in the design of high-efficiency power amplifiers (PAs). The study evaluates the performance of harmonically tuned amplifiers, tackling concurrently both input and output harmonics. The proposed theory starts with deriving an altered input voltage waveform under the impact of input nonlinearity. Intrinsic drain voltage and drain current components are formulated as a function of the conduction angle $\alpha $ considering both source and load terminations. Output power and drain efficiency are then computed as a function of input nonlinearity, $\alpha $ , and output loading conditions. The derived formulations allow to investigate the design sensitivity to input nonlinearity and its impact on fundamental design space. The impact of source harmonics is evaluated using harmonic source pull under different output loading conditions. Thereafter, PA design and implementation has been carried out using NXP 1.95 mm die to confirm the distinctive behavior of class GF and GF−1 amplifiers with respect to the input harmonic terminations. For practical validation, four different design cases with different second harmonic source impedances are investigated. At 2.6 GHz, drain efficiencies ranging between 76% and 83% were exhibited depending on the source and load harmonic tuning for each design case. Measurement results confirm the theoretical findings reported in this paper.
TL;DR: In this paper, the authors provide a unified perspective of the unique opportunities created by operating at high repetition rates together with efforts into the development of enabling laser technology, including new results on further scaling up the capabilities of the laser systems.
Abstract: Ultrafast lasers operating at high repetition rates, in particular the GHz range, enable new possibilities in laser-material processing, particularly accessing the recently demonstrated ablation-cooled regime. We provide a unified perspective of the unique opportunities created by operating at high repetition rates together with our efforts into the development of enabling laser technology, including new results on further scaling up the capabilities of the laser systems. In order to access GHz repetition rates and microjoule-level pulse energies without requiring kilowatts of average power, we implement burst-mode operation. Our results can be grouped into two distinct directions: low- and high-power systems. Pulsed pumping is employed in the later stages of low-power systems, which have low burst repetition rates to achieve high pulse energies, whereas the technique of doping management is developed for the continuously pumped power amplifier stage of high power systems. While most of the developments have been at 1- $\mu$ m wavelength range due to the relative maturity of the laser technology, we also report the development of Tm-fiber lasers around the 2- $\mu$ m region specifically for tissue processing and laser-surgery applications.
TL;DR: An efficient method for compressing sub-picosecond pulses at 200 W average power with 2 mJ pulse energy in a multipass cell filled with different gases is presented, which represents an excellent alternative to hollow-core fiber-based compression schemes and optical parametric amplifiers.
Abstract: We present an efficient method for compressing sub-picosecond pulses at 200 W average power with 2 mJ pulse energy in a multipass cell filled with different gases. We demonstrate spectral broadening by more than a factor of five using neon, argon, and nitrogen as nonlinear media. The 210 fs input pulses are compressed down to 37 fs and 35 GW peak power with a beam quality factor of 1.3×1.5 at a power throughput of >93%. This concept represents an excellent alternative to hollow-core fiber-based compression schemes and optical parametric amplifiers (OPAs).
TL;DR: The authors use in-line phase-sensitive amplifiers to show a long-haul optical link with a 5.6-times reach improvement over conventional amplifier performance, affirming their viability as an alternative technology.
Abstract: The capacity and reach of long-haul fiber optical communication systems is limited by in-line amplifier noise and fiber nonlinearities. Phase-sensitive amplifiers add 6 dB less noise than conventional phase-insensitive amplifiers, such as erbium-doped fiber amplifiers, and they can provide nonlinearity mitigation after each span. Realizing a long-haul transmission link with in-line phase-sensitive amplifiers providing simultaneous low-noise amplification and nonlinearity mitigation is challenging and to date no such transmission link has been demonstrated. Here, we demonstrate a multi-channel-compatible and modulation-format-independent long-haul transmission link with in-line phase-sensitive amplifiers. Compared to a link amplified by conventional erbium-doped fiber amplifiers, we demonstrate a reach improvement of 5.6 times at optimal launch powers with the phase-sensitively amplified link operating at a total accumulated nonlinear phase shift of 6.2 rad. The phase-sensitively amplified link transmits two data-carrying waves, thus occupying twice the bandwidth and propagating twice the total power compared to the phase-insensitively amplified link.
10 Jun 2018
TL;DR: A high output power, high gain, class-AB power amplifier (PA) in 40 nm CMOS technology for D-band applications and two-way transformer-based power-combining is implemented in order to increase output power.
Abstract: This paper presents a high output power, high gain, class-AB power amplifier (PA) in 40 nm CMOS technology for D-band applications. Two-way transformer-based power-combining is implemented in order to increase output power. The supply voltage of the designed PA is 1 V. The PA achieves a P SAT of 14.8 dBm, small-signal gain of 20.3 dB and maximum PAE of 8.9 % at 140 GHz.
TL;DR: In this article, the authors present an analysis and design technique for an RF-input load modulated balanced amplifier (LMBA) with Doherty-like efficiency enhancement characteristics, in which a control signal is injected into the isolation port of the output coupler of a balanced amplifier.
Abstract: This paper presents an analysis and design technique for an RF-input load modulated balanced amplifier (LMBA) with Doherty-like efficiency enhancement characteristics. The LMBA is a recently introduced power amplifier (PA) architecture in which a control signal is injected into the isolation port of the output coupler of a balanced amplifier. This control signal modulates the apparent load impedance of the two main devices. In the RF-input LMBA presented in this paper, the control signal is generated from the single-modulated RF input using a class-C control amplifier, producing an overall Doherty-like response. A complete theoretical analysis of the RF-input LMBA is presented, by assuming generalized networks for the output combiner and input splitter which are then solved in terms of transistor parameters and boundary conditions for high efficiency. Based on this analysis, a generalized design technique is presented. The LMBA is, thereby, shown to have advantages over the Doherty PA, including the device periphery scaling between the main and control devices for a given back-off range. The design technique is demonstrated at 2.4 GHz using packaged GaN devices. The prototype has a peak CW output power of 45.6 dBm, with a power-added efficiency of 60% at peak power and 50% at 6-dB output back-off, including the power dissipated by the control PA. A long-term evolution signal at 2.4 GHz with a 7.5-dB peak-to-average power ratio is demonstrated with an unlinearized ACLR of −27 dBc and an average drain efficiency of 47% for a 38-dBm average output power.
TL;DR: Theoretical study of erbium-doped fiber amplifiers-based space division multiplexing (SDM) transmission shows the existence of optimal values of spectral efficiency, signal-to-noise ratio, and span length that maximize power efficiency as mentioned in this paper.
Abstract: We discuss space division multiplexing as a means of increasing link capacity for power limited transmission in undersea communication. Theoretical study of erbium-doped fiber amplifiers-based space division multiplexing (SDM) transmission shows the existence of optimal values of spectral efficiency, signal-to-noise ratio, and span length that maximize power efficiency. We experimentally confirm the existence of an optimal spectral efficiency and demonstrate power efficient SDM transmission using 12-core multicore fiber. Modulation format, amplifier, and link design are discussed in connection to SDM power efficient transmission.
TL;DR: In this paper, a transmitter coil and a receiver coil were designed at 6.78 MHz for magnetic resonant wireless power transfer systems not only to have high efficiency at medium distances, which is comparable to the coil dimensions, but also to provide stable efficiency over the position variation of the receiver coil.
Abstract: A transmitter coil (TX-coil) as well as a receiver coil (RX-coil) has been designed at 6.78 MHz for magnetic resonant wireless power transfer systems not only to have high efficiency at medium distances, which is comparable to the coil dimensions, but also to provide stable efficiency over the position variation of the RX-coil. For mobile devices, the coils should be compact and have low profile and asymmetric, meaning that TX- and RX-coils have different dimensions. In this paper, TX-coil is designed by adding a small coil in series to achieve high quality factor (Q-factor) as well as relatively uniform magnetic field distribution. On the other hand, the scaling factor is introduced for wire width to design RX-coil with higher Q-factor. As a result, the proposed asymmetric coils reveal improved efficiency and degree of freedom in terms of position variation. This has been verified by measuring the system performance, including a power amplifier, full-wave rectifier, regulator, and load. The proposed TX-coil has size of $200 \times 200 \times 1$ mm3, while the size of the RX-coil is $100\times 100\times0.4$ mm3. The power transfer efficiency is 96% and 39% at the transmission distances of 50 and 300 mm, respectively.
TL;DR: This brief presents a design procedure of a compact 33-GHz low-noise amplifier (LNA) for fifth generation (5G) applications realized in 28-nm LP CMOS, with emphasis on the optimization of design and layout techniques for active and passive components in the presence of rigorous metal density rules and other back-end-of-the-line challenges.
Abstract: This brief presents a design procedure of a compact 33-GHz low-noise amplifier (LNA) for fifth generation (5G) applications realized in 28-nm LP CMOS. Based on the unique set of challenges presented by advanced nanoscale CMOS, the emphasis is put here on the optimization of design and layout techniques for active and passive components in the presence of rigorous metal density rules and other back-end-of-the-line challenges. All passive components are designed and optimized with full-wave electromagnetic simulations for a high quality factor. In addition, layout techniques help to miniaturize the total area as the suggested 5G frequency band of 33 GHz is not high enough to provide a sufficiently compact chip size. The resulting increase in the concentration of required metal fills furthermore makes this optimization more challenging. The fabricated LNA consists of two cascode stages with a total core area of $0.68{\times }0.34$ mm2. It exhibits 4.9-dB noise figure and 18.6-dB gain at 33 GHz while consuming only 9.7 mW from a 1.2-V power supply.