An all-fiber polarization maintaining high-power laser system operating at 1.7 μm based on the Ramaninduced soliton self-frequency shifting effect is demonstrated. The entirely fiberized system is built by erbiumdope...An all-fiber polarization maintaining high-power laser system operating at 1.7 μm based on the Ramaninduced soliton self-frequency shifting effect is demonstrated. The entirely fiberized system is built by erbiumdoped oscillator and two-stage amplifiers with polarization maintaining commercial silica fibers and devices, which can provide robust and stable soliton generation. High-power soliton laser with the average power of 0.28 W,the repetition rate of 42.7 MHz, and pulse duration of 515 fs is generated directly from the main amplifier.Our experiment provides a feasible method for high-power all-fiber polarization maintaining femtosecond laser generation working at 1.7 μm.展开更多
In this paper,a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier(DPA)is presented.In the presented approaches,the signal separation function(SSF)at different frequency poi...In this paper,a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier(DPA)is presented.In the presented approaches,the signal separation function(SSF)at different frequency points can be characterized by a polynomial.And in the practical test,the coefficients of SSF can be determined by measuring a small number of data points of input power.Same as other dualinput DPAs,the proposed approach can also achieve high output power and back-off efficiency in a broadband operation band by adjusting the power distribution ratio flexibly.Finally,a 1.5-2.5 GHz highefficiency dual-input Doherty power amplifier is implemented according to this approach.The test results show that the peak power is 48.6-49.7d Bm,and the 6-d B back-off efficiency is 51.0-67.0%,and the saturation efficiency is 52.4-74.6%.The digital predistortion correction is carried out at the frequency points of 1.8/2.1GHz,and the adjacent channel power ratio is lower than-54.5d Bc.Simulation and experiment results can verify the effectiveness and correctness of the proposed method.展开更多
A Josephson traveling wave parametric amplifier(JTWPA),which is a quantum-limited amplifier with high gain and large bandwidth,is the core device of large-scale measurement and control systems for quantum computing.A ...A Josephson traveling wave parametric amplifier(JTWPA),which is a quantum-limited amplifier with high gain and large bandwidth,is the core device of large-scale measurement and control systems for quantum computing.A typical JTWPA consists of thousands of Josephson junctions connected in series to form a transmission line and hundreds of shunt LC resonators periodically loaded along the line for phase matching.Because the variation of these capacitors and inductors can be detrimental to their high-frequency characteristics,the fabrication of a JTWPA typically necessitates precise processing equipment.To guide the fabrication process and further improve the design for manufacturability,it is necessary to understand how each electronic component affects the amplifier.In this paper,we use the harmonic balance method to conduct a comprehensive study on the impact of nonuniformity and fabrication yield of the electronic components on the performance of a JTWPA.The results provide insightful and scientific guidance for device design and fabrication processes.展开更多
For time-of-flight(TOF)light detection and ranging(LiDAR),a three-channel high-performance transimpedance amplifier(TIA)with high immunity to input load capacitance is presented.A regulated cascade(RGC)as the input st...For time-of-flight(TOF)light detection and ranging(LiDAR),a three-channel high-performance transimpedance amplifier(TIA)with high immunity to input load capacitance is presented.A regulated cascade(RGC)as the input stage is at the core of the complementary metal oxide semiconductor(CMOS)circuit chip,giving it more immunity to input photodiode detectors.A simple smart output interface acting as a feedback structure,which is rarely found in other designs,reduces the chip size and power consumption simultaneously.The circuit is designed using a 0.5μm CMOS process technology to achieve low cost.The device delivers a 33.87 dB?transimpedance gain at 350 MHz.With a higher input load capacitance,it shows a-3 dB bandwidth of 461 MHz,indicating a better detector tolerance at the front end of the system.Under a 3.3 V supply voltage,the device consumes 5.2 mW,and the total chip area with three channels is 402.8×597.0μm2(including the test pads).展开更多
In this paper,a 5G wideband power amplifier(PA)with bandpass filtering response is synthesized using a bandwidth-extended bandpass filter as the matching network(MN).In this structure,the bandwidth(θ_(C))is defined a...In this paper,a 5G wideband power amplifier(PA)with bandpass filtering response is synthesized using a bandwidth-extended bandpass filter as the matching network(MN).In this structure,the bandwidth(θ_(C))is defined as a variable in the closedform equations provided by the microstrip bandpass filter.It can be extended over a wide range only by changing the characteristic impedances of the structure.Different from the other wideband MNs,the extension of bandwidth does not increase the complexity of the structure(order n is fixed).In addition,based on the bandwidth-extended structure,the wideband design of bandpass filtering PA is not limited to the fixed bandwidth of the specific filter structure.The theoretical analysis of the MN and the design flow of the PA are provided in this design.The fabricated bandpass filtering PA can support almost one-octave bandwidth(2-3.8 GHz),covering the two 5G bands(n41 and n78).The drain efficiency of 47%-60%and output power higher than 40 dBm are measured.Good frequency selectivity in S-parameter measurements can be observed.展开更多
Considering the R&D for upgrading the K^(0)_(L) andμdetectors in the Belle II experiment using a scintillator and silicon pho-tomultiplier(SiPM),we designed a compact high-speed and low-noise preamplifier.The pre...Considering the R&D for upgrading the K^(0)_(L) andμdetectors in the Belle II experiment using a scintillator and silicon pho-tomultiplier(SiPM),we designed a compact high-speed and low-noise preamplifier.The preamplifier demonstrated a good gain stability,bandwidth of 426 MHz,baseline noise level ofσ≈0.6 mV,dynamic range of up to170 mV of the input signal amplitude,good time resolution of 20 ps,and it can be comprehensively applied to SiPMs.Adopting pole-zero-cancelation in the preamplifier reduces both the rise and fall times of the SiPM signal,which can significantly improve the time resolution and reduce the pile-up when using a large SiPM or an array of SiPMs.Various combinations of the preamplifier and several types of SiPMs demonstrated time resolutions better than 50 ps for most cases;when the number of detected photons was larger than 60,a time resolution of approximately 25 ps was achieved.展开更多
Impact of amplified spontaneous emission(ASE)noise on the stimulated Raman scattering(SRS)threshold of highpower fiber amplifiers is demonstrated numerically through a spectral evolution approach.The simulation result...Impact of amplified spontaneous emission(ASE)noise on the stimulated Raman scattering(SRS)threshold of highpower fiber amplifiers is demonstrated numerically through a spectral evolution approach.The simulation results confirm that ASE noise in the Raman wavelength band could reduce the SRS threshold of high-power fiber amplifiers significantly.As for ASE noise originated the main amplifier,it becomes stronger and reduces the SRS threshold at shorter operation wavelength below 1052 nm.As for ASE noise originated from the seed laser,it reduces the SRS threshold at different operation wavelength under the condition that the Raman ratio is over-90 dB in the seed laser.The theoretical method and results in this work could provide a well reference to extend the operation wavelength of high-power fiber lasers.展开更多
A hybrid linear amplifier is inserted at the output of the source-in-the-middle distribution protocol to overcome the shortcomings of the transmission distance.The modified protocol aims to maintain a high key rate fo...A hybrid linear amplifier is inserted at the output of the source-in-the-middle distribution protocol to overcome the shortcomings of the transmission distance.The modified protocol aims to maintain a high key rate for long-distance transmission under high noise.It has the potential to significantly broaden the application range of the continuous variable quantum key distribution protocol.The effects of amplifier parameters and noise on the modified protocol are analyzed in detail with regard to applying it to a practical system.To make the simulation more realistic,the effect of finite size on the new protocol is taken into account.It will serve as a guideline for the future use of hybrid linear amplifiers.Different parameters can be adjusted to achieve the best performance for key rates of different quantum channels.展开更多
We study the effect of an amplification mechanism in a nonlinear vibration energy harvesting system where a ferromagnetic beam resonator is attached to the vibration source through an additional linear spring with a d...We study the effect of an amplification mechanism in a nonlinear vibration energy harvesting system where a ferromagnetic beam resonator is attached to the vibration source through an additional linear spring with a damper.The beam moves in the nonlinear double-well potential caused by interaction with two magnets.The piezoelectric patches with electrodes attached to the electrical circuit support mechanical energy transduction into electrical power.The results show that the additional spring can improve energy harvesting.By changing its stiffness,we observed various solutions.At the point of the optimal stiffness of the additional spring,the power output is amplified a few times depending on the excitation amplitude.展开更多
In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development ...In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development of silicon-based THz PAs,mainly including silicon-based PAs with operating frequencies covering 100–300 GHz,are summarized in this paper.Particularly,we design an LC-balun-based two-stage differential cascode PA with a center frequency of 150 GHz and an output power of 14 dBm.Based on a Marchand balun,we report a 220 GHz three-stage differential cascode PA with a saturated output power of 9.5 dBm.To further increase the output power of THz PA,based on a four-way differential power combining technique,we report a 211–263 GHz dual-LC-tank-based broadband PA with a recorded 14.7 dBm Psat and 16.4 dB peak gain.All the above circuits are designed in a standard 130 nm silicon germanium(SiGe)BiCMOS process.展开更多
To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper ...To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper constructs pure nonlinear stiffness without neglecting the gravity effect of the oscillator. Both analytical and numerical methods are used to evaluate the performance of the NES-IA. The research findings indicate that even if the actual mass is 1% of the main oscillator, the NES-IA with proper inertia angles and mass distribution ratios can still effectively attenuate the steady-state and transient responses of the main oscillator. Nonlinear stiffness and damping also have important effects. Due to strongly nonlinear factors, the coupled system may exhibit higher branch responses under harmonic excitation. In shock excitation environment, the NES-IA with a large dynamic mass can trigger energy capture of both main resonance and high-frequency resonance. Furthermore, the comparison with the traditional NES also confirms the advantages of the NES-IA in overcoming mass dependence.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10225417 and 61675009)the Natural Science Foundation of Beijing Municipality (Grant Nos. 4204091 and KZ201910005006)the China Postdoctoral Science Foundation (Grant No. 212423)。
文摘An all-fiber polarization maintaining high-power laser system operating at 1.7 μm based on the Ramaninduced soliton self-frequency shifting effect is demonstrated. The entirely fiberized system is built by erbiumdoped oscillator and two-stage amplifiers with polarization maintaining commercial silica fibers and devices, which can provide robust and stable soliton generation. High-power soliton laser with the average power of 0.28 W,the repetition rate of 42.7 MHz, and pulse duration of 515 fs is generated directly from the main amplifier.Our experiment provides a feasible method for high-power all-fiber polarization maintaining femtosecond laser generation working at 1.7 μm.
基金supported by National Natural Science Foundation of China(No.62001061)。
文摘In this paper,a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier(DPA)is presented.In the presented approaches,the signal separation function(SSF)at different frequency points can be characterized by a polynomial.And in the practical test,the coefficients of SSF can be determined by measuring a small number of data points of input power.Same as other dualinput DPAs,the proposed approach can also achieve high output power and back-off efficiency in a broadband operation band by adjusting the power distribution ratio flexibly.Finally,a 1.5-2.5 GHz highefficiency dual-input Doherty power amplifier is implemented according to this approach.The test results show that the peak power is 48.6-49.7d Bm,and the 6-d B back-off efficiency is 51.0-67.0%,and the saturation efficiency is 52.4-74.6%.The digital predistortion correction is carried out at the frequency points of 1.8/2.1GHz,and the adjacent channel power ratio is lower than-54.5d Bc.Simulation and experiment results can verify the effectiveness and correctness of the proposed method.
基金support from the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No.2019319)support from the Start-up Foundation of Suzhou Institute of Nano-Tech and Nano-Bionics,CAS,Suzhou (Grant No.Y9AAD110)。
文摘A Josephson traveling wave parametric amplifier(JTWPA),which is a quantum-limited amplifier with high gain and large bandwidth,is the core device of large-scale measurement and control systems for quantum computing.A typical JTWPA consists of thousands of Josephson junctions connected in series to form a transmission line and hundreds of shunt LC resonators periodically loaded along the line for phase matching.Because the variation of these capacitors and inductors can be detrimental to their high-frequency characteristics,the fabrication of a JTWPA typically necessitates precise processing equipment.To guide the fabrication process and further improve the design for manufacturability,it is necessary to understand how each electronic component affects the amplifier.In this paper,we use the harmonic balance method to conduct a comprehensive study on the impact of nonuniformity and fabrication yield of the electronic components on the performance of a JTWPA.The results provide insightful and scientific guidance for device design and fabrication processes.
文摘For time-of-flight(TOF)light detection and ranging(LiDAR),a three-channel high-performance transimpedance amplifier(TIA)with high immunity to input load capacitance is presented.A regulated cascade(RGC)as the input stage is at the core of the complementary metal oxide semiconductor(CMOS)circuit chip,giving it more immunity to input photodiode detectors.A simple smart output interface acting as a feedback structure,which is rarely found in other designs,reduces the chip size and power consumption simultaneously.The circuit is designed using a 0.5μm CMOS process technology to achieve low cost.The device delivers a 33.87 dB?transimpedance gain at 350 MHz.With a higher input load capacitance,it shows a-3 dB bandwidth of 461 MHz,indicating a better detector tolerance at the front end of the system.Under a 3.3 V supply voltage,the device consumes 5.2 mW,and the total chip area with three channels is 402.8×597.0μm2(including the test pads).
基金supported by National Natural Science Foundations of China (No.61971052 and No.U20A20203)Key Research and Development Project of Guangdong Province (2020B0101080001)
文摘In this paper,a 5G wideband power amplifier(PA)with bandpass filtering response is synthesized using a bandwidth-extended bandpass filter as the matching network(MN).In this structure,the bandwidth(θ_(C))is defined as a variable in the closedform equations provided by the microstrip bandpass filter.It can be extended over a wide range only by changing the characteristic impedances of the structure.Different from the other wideband MNs,the extension of bandwidth does not increase the complexity of the structure(order n is fixed).In addition,based on the bandwidth-extended structure,the wideband design of bandpass filtering PA is not limited to the fixed bandwidth of the specific filter structure.The theoretical analysis of the MN and the design flow of the PA are provided in this design.The fabricated bandpass filtering PA can support almost one-octave bandwidth(2-3.8 GHz),covering the two 5G bands(n41 and n78).The drain efficiency of 47%-60%and output power higher than 40 dBm are measured.Good frequency selectivity in S-parameter measurements can be observed.
基金This work was partially supported by the National Key R&D Program of China(No.2022YFA1601903)the National Natural Science Foundation of China(Nos.11925502,11961141003,and 12175041)the Strategic Priority Research Program of the CAS(No.XDB34030000).
文摘Considering the R&D for upgrading the K^(0)_(L) andμdetectors in the Belle II experiment using a scintillator and silicon pho-tomultiplier(SiPM),we designed a compact high-speed and low-noise preamplifier.The preamplifier demonstrated a good gain stability,bandwidth of 426 MHz,baseline noise level ofσ≈0.6 mV,dynamic range of up to170 mV of the input signal amplitude,good time resolution of 20 ps,and it can be comprehensively applied to SiPMs.Adopting pole-zero-cancelation in the preamplifier reduces both the rise and fall times of the SiPM signal,which can significantly improve the time resolution and reduce the pile-up when using a large SiPM or an array of SiPMs.Various combinations of the preamplifier and several types of SiPMs demonstrated time resolutions better than 50 ps for most cases;when the number of detected photons was larger than 60,a time resolution of approximately 25 ps was achieved.
基金the National Natural Science Foundation of China(Grant Nos.62005313 and 62061136013).
文摘Impact of amplified spontaneous emission(ASE)noise on the stimulated Raman scattering(SRS)threshold of highpower fiber amplifiers is demonstrated numerically through a spectral evolution approach.The simulation results confirm that ASE noise in the Raman wavelength band could reduce the SRS threshold of high-power fiber amplifiers significantly.As for ASE noise originated the main amplifier,it becomes stronger and reduces the SRS threshold at shorter operation wavelength below 1052 nm.As for ASE noise originated from the seed laser,it reduces the SRS threshold at different operation wavelength under the condition that the Raman ratio is over-90 dB in the seed laser.The theoretical method and results in this work could provide a well reference to extend the operation wavelength of high-power fiber lasers.
基金Project supported by the National Natural Science Foundation of China(Grant No.62201620)the Outstanding Youth Program of Education Department of Hunan(Grant No.21B0228)+2 种基金Changsha Municipal Natural Science Foundation(Grant No.kq2202293)Hunan Students’Platform for innovation and entrepreneurship training program(Grant No.S202210538069)the Research Fund of Central South University of Forestry and Technology(Grant No.1121001703).
文摘A hybrid linear amplifier is inserted at the output of the source-in-the-middle distribution protocol to overcome the shortcomings of the transmission distance.The modified protocol aims to maintain a high key rate for long-distance transmission under high noise.It has the potential to significantly broaden the application range of the continuous variable quantum key distribution protocol.The effects of amplifier parameters and noise on the modified protocol are analyzed in detail with regard to applying it to a practical system.To make the simulation more realistic,the effect of finite size on the new protocol is taken into account.It will serve as a guideline for the future use of hybrid linear amplifiers.Different parameters can be adjusted to achieve the best performance for key rates of different quantum channels.
基金funded by National Science Centre,Poland(Grant No.2021/40/Q/ST8/00362)Brazilian agencies:Coordena??o de Aperfei?oamento de Pessoal de Nível Superior(CAPES)+1 种基金Finance Code 001,Conselho Nacional de Desenvolvimento Científico e Tecnológico(Grant No.305476/2022-0)Funda?ao Carlos Chagas Filho de Am-paroáPesquisa do Estado do Rio de Janeiro(Grant Nos.210.167/2019,211.037/2019 and 201.294/2021)。
文摘We study the effect of an amplification mechanism in a nonlinear vibration energy harvesting system where a ferromagnetic beam resonator is attached to the vibration source through an additional linear spring with a damper.The beam moves in the nonlinear double-well potential caused by interaction with two magnets.The piezoelectric patches with electrodes attached to the electrical circuit support mechanical energy transduction into electrical power.The results show that the additional spring can improve energy harvesting.By changing its stiffness,we observed various solutions.At the point of the optimal stiffness of the additional spring,the power output is amplified a few times depending on the excitation amplitude.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62101117 and 62188102in part by ZTE Industry-University-Institute Cooperation Fundsin part by the Project funded by China Postdoctoral Science Foundation under Grant Nos.2021M700763 and 2022T150113.
文摘In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development of silicon-based THz PAs,mainly including silicon-based PAs with operating frequencies covering 100–300 GHz,are summarized in this paper.Particularly,we design an LC-balun-based two-stage differential cascode PA with a center frequency of 150 GHz and an output power of 14 dBm.Based on a Marchand balun,we report a 220 GHz three-stage differential cascode PA with a saturated output power of 9.5 dBm.To further increase the output power of THz PA,based on a four-way differential power combining technique,we report a 211–263 GHz dual-LC-tank-based broadband PA with a recorded 14.7 dBm Psat and 16.4 dB peak gain.All the above circuits are designed in a standard 130 nm silicon germanium(SiGe)BiCMOS process.
基金Project supported by the National Natural Science Foundation of China (Nos. 12172014 and11972050)the Key Laboratory of Vibration and Control of Aero-Propulsion System (Northeastern University),Ministry of Education of China (No. VCAME 202004)。
文摘To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper constructs pure nonlinear stiffness without neglecting the gravity effect of the oscillator. Both analytical and numerical methods are used to evaluate the performance of the NES-IA. The research findings indicate that even if the actual mass is 1% of the main oscillator, the NES-IA with proper inertia angles and mass distribution ratios can still effectively attenuate the steady-state and transient responses of the main oscillator. Nonlinear stiffness and damping also have important effects. Due to strongly nonlinear factors, the coupled system may exhibit higher branch responses under harmonic excitation. In shock excitation environment, the NES-IA with a large dynamic mass can trigger energy capture of both main resonance and high-frequency resonance. Furthermore, the comparison with the traditional NES also confirms the advantages of the NES-IA in overcoming mass dependence.