The research of high-performance polarization controllers is of great significance for expanding the application field of polarization optics. Here, a polarization switch is demonstrated by using a dual-core photonic ...The research of high-performance polarization controllers is of great significance for expanding the application field of polarization optics. Here, a polarization switch is demonstrated by using a dual-core photonic crystal fiber(DCPCF)with four symmetrical air holes, placed above and below each core, filled with magnetic fluid(MF). The switch, which utilizes a magnetic field to change the coupling length ratio of the x and y polarization modes, enables dynamic tuning of the polarization state and extinction ratio. Numerical results show that when the working length is 36.638 mm, the magneto–optical polarization switch can operate in four communication bands, i.e., 1509 nm to 1520 nm, 1544 nm to1556 nm, 1578 nm to 1591 nm, and 1611 nm to 1624 nm. Moreover, the extinction ratio(ER) is greater than 20 d B in the fiber length range of 38.5 mm to 38.7 mm, indicating that the device has a good fault tolerance for the interception of the fiber length.展开更多
An ultra-broadband polarization splitter based on graphene layer-filled dual-core photonic crystal fiber(GDC-PCF)that can work in a wavelength range from 1120 nm to 1730 nm is proposed in this paper. Through optimizin...An ultra-broadband polarization splitter based on graphene layer-filled dual-core photonic crystal fiber(GDC-PCF)that can work in a wavelength range from 1120 nm to 1730 nm is proposed in this paper. Through optimizing fiber configuration, the polarization splitter has an extinction ratio of-56.3 dB at 1.55 μm with a fiber length of 4.8 mm.Compared with the photonic crystal fiber reported splitters, to our knowledge, the GDC-PCF splitter with the extinction ratio below-20 dB has a super wide bandwidth of 610 nm. Due to the excellent splitting characteristics, the GDC-PCF will be used in coherent optical communication systems in a wavelength range from infrared to mid-infraed.展开更多
This paper theoretically investigates the dependence of leaky mode coupling between inner core fundamental mode and outer core defect mode on phase and loss matching in pure silica dual-core photonic crystal fibres wi...This paper theoretically investigates the dependence of leaky mode coupling between inner core fundamental mode and outer core defect mode on phase and loss matching in pure silica dual-core photonic crystal fibres with the multi-pole method. The complete mode coupling can take place when both the phase and loss matching conditions are satisfied at the avoided anti-crossing wavelength. It shows the influences of cladding structure parameters including the diameters of cladding air holes d1, diameters of outer core holes d2 and hole to hole pitch Λ on the characteristics of leaky modes coupling. The coupled-mode theory is used to analyse the mode transition characteristics and the complete coupling can be clearly indicated by comparing the real and imaginary parts of propagation constant of the leaky modes.展开更多
In this paper, we present a mode-selective coupler based on a dual-core all-solid photonic bandgap fiber（AS-PBGF）. Because they are all-solid, AS-PBGF-based mode converters are easier to splice to other fibers than ...In this paper, we present a mode-selective coupler based on a dual-core all-solid photonic bandgap fiber（AS-PBGF）. Because they are all-solid, AS-PBGF-based mode converters are easier to splice to other fibers than those based on air-hole photonic crystal fibers. Mode conversions between the LP01 and LP11modes, LP01 and LP21modes, and LP01 and LP02modes are obtained at the wavelength λ=1550 nm. The 3 dB wavelength bandwidth of these mode converters are 47.8,20.3, and 20.3 nm, respectively.展开更多
Lithium-sulfur batteries are severely restricted by low electronic conductivity of sulfur and Li_(2)S,shuttle effect,and slow conversion reaction of lithium polysulfides(LiPSs).Herein,we report a facile and highyield ...Lithium-sulfur batteries are severely restricted by low electronic conductivity of sulfur and Li_(2)S,shuttle effect,and slow conversion reaction of lithium polysulfides(LiPSs).Herein,we report a facile and highyield strategy for synthesizing dual-core single-atom catalyst(ZnCoN_(4)O_(2)/CN)with atomically dispersed nitrogen/oxygen-coordinated Zn-Co sites on carbon nanosheets.Based on density functional theory(DFT)calculations and LiPSs conversion catalytic ability,ZnCoN_(4)O_(2)/CN provides dual-atom sites of Zn and Co,which could facilitate Li^(+)transport and Li_(2)S diffusion,and catalyze LiPSs conversion more effectively than homonuclear bimetallic single-atom catalysts or their simple mixture and previously reported singleatom catalysts.Li-S cell with ZnCoN_(4)O_(2)/CN modified separator showed excellent rate performance(789.4 mA h g^(-1)at 5 C)and stable long cycle performance(0.05%capacity decay rate at 6C with 1000cycles,outperforming currently reported single atomic catalysts for LiPSs conversion.This work highlights the important role of metal active centers and provides a strategy for producing multifunctional dual-core single atom catalysts for high-performance Li-S cells.展开更多
针对三冗余机电静压伺服系统的研制需求,设计了基于双核全可编程片上系统(All Programmable System on Chip,APSoC)技术的多总线三冗余伺服控制驱动器。通过数字总线实现子控制驱动模块之间信息共享,采用IP核技术实现硬件加速、多电机...针对三冗余机电静压伺服系统的研制需求,设计了基于双核全可编程片上系统(All Programmable System on Chip,APSoC)技术的多总线三冗余伺服控制驱动器。通过数字总线实现子控制驱动模块之间信息共享,采用IP核技术实现硬件加速、多电机高速并行控制;通过试验验证多电机控制的同步性能和测量细节全还原技术;采用多种温度、压力传感器、过流保护电路等构建伺服系统健康网络体系,结合余度表决和故障切除逻辑搭建了三冗余控制驱动平台,对多任务的不同实时性需求分配任务等级,双核协同工作,研制的产品实物通过了系统验证。展开更多
基金supported by the National Key Research and Development Program of China “National Quality Infrastructure” (Grant No. 2021YFF0600902)。
文摘The research of high-performance polarization controllers is of great significance for expanding the application field of polarization optics. Here, a polarization switch is demonstrated by using a dual-core photonic crystal fiber(DCPCF)with four symmetrical air holes, placed above and below each core, filled with magnetic fluid(MF). The switch, which utilizes a magnetic field to change the coupling length ratio of the x and y polarization modes, enables dynamic tuning of the polarization state and extinction ratio. Numerical results show that when the working length is 36.638 mm, the magneto–optical polarization switch can operate in four communication bands, i.e., 1509 nm to 1520 nm, 1544 nm to1556 nm, 1578 nm to 1591 nm, and 1611 nm to 1624 nm. Moreover, the extinction ratio(ER) is greater than 20 d B in the fiber length range of 38.5 mm to 38.7 mm, indicating that the device has a good fault tolerance for the interception of the fiber length.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61405096 and 61504058)the Introduction of Talent Research and Research Fund of Nanjing University of Posts and Telecommunications,China(Grant No.NY214158)+1 种基金the Open Fund of Laboratory of Solid State Microstructures,Nanjing University,China(Grant No.M28035)the Open Fund of State Key Laboratory of Transient Optics and Photonics,Chinese Academy of Sciences(Grant No.SKLST201404)
文摘An ultra-broadband polarization splitter based on graphene layer-filled dual-core photonic crystal fiber(GDC-PCF)that can work in a wavelength range from 1120 nm to 1730 nm is proposed in this paper. Through optimizing fiber configuration, the polarization splitter has an extinction ratio of-56.3 dB at 1.55 μm with a fiber length of 4.8 mm.Compared with the photonic crystal fiber reported splitters, to our knowledge, the GDC-PCF splitter with the extinction ratio below-20 dB has a super wide bandwidth of 610 nm. Due to the excellent splitting characteristics, the GDC-PCF will be used in coherent optical communication systems in a wavelength range from infrared to mid-infraed.
基金Project supported by the National Key Basic Research Special Foundation of China (Grant No. 2010CB327605)the National High-Technology Research and Development Program of China (Grant No. 2009AA01Z220)+2 种基金the Key Grant of the Chinese Ministry of Education (Grant No. 109015)the Discipline Co-construction Project of Beijing Municipal Commission of Education (Grant No. YB20081001301)the Open Fund of Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), Ministry of Education,and the Specialized Research Fund for the Doctoral Program of Beijing University of Posts and Telecommunications (Grant No. CX201023)
文摘This paper theoretically investigates the dependence of leaky mode coupling between inner core fundamental mode and outer core defect mode on phase and loss matching in pure silica dual-core photonic crystal fibres with the multi-pole method. The complete mode coupling can take place when both the phase and loss matching conditions are satisfied at the avoided anti-crossing wavelength. It shows the influences of cladding structure parameters including the diameters of cladding air holes d1, diameters of outer core holes d2 and hole to hole pitch Λ on the characteristics of leaky modes coupling. The coupled-mode theory is used to analyse the mode transition characteristics and the complete coupling can be clearly indicated by comparing the real and imaginary parts of propagation constant of the leaky modes.
基金the National Basic Research Program of China (973 Program) under Grant 2014CB340102the National Natural Science Foundation under Grants 61271191 and 61271193the Fund of State Key Laboratory of Information Photonics and Optical Communications
文摘In this paper, we present a mode-selective coupler based on a dual-core all-solid photonic bandgap fiber（AS-PBGF）. Because they are all-solid, AS-PBGF-based mode converters are easier to splice to other fibers than those based on air-hole photonic crystal fibers. Mode conversions between the LP01 and LP11modes, LP01 and LP21modes, and LP01 and LP02modes are obtained at the wavelength λ=1550 nm. The 3 dB wavelength bandwidth of these mode converters are 47.8,20.3, and 20.3 nm, respectively.
基金supported by the National Natural Science Foundation of P.R.China(22001082)the Applied Science and Technology Planning Project of Guangdong Province,Guangzhou,China(2017B090917002)+5 种基金the Guangdong Basic and Applied Basic Research Fund Project(2019B1515120027)the Research and Development(R&D)Projects in Key Areas of Guangdong Province(2020B0101028005)the Guangdong Natural Science Foundation Project(No.2019A1515010841)the Guangdong Province International Science and Technology Cooperation Project(No.2019A050510038)the Guangzhou Science and Technology Association Young Talents Promotion Project(X20210201043)the Guangzhou Basic and Applied Basic Research Project(202102020624)。
文摘Lithium-sulfur batteries are severely restricted by low electronic conductivity of sulfur and Li_(2)S,shuttle effect,and slow conversion reaction of lithium polysulfides(LiPSs).Herein,we report a facile and highyield strategy for synthesizing dual-core single-atom catalyst(ZnCoN_(4)O_(2)/CN)with atomically dispersed nitrogen/oxygen-coordinated Zn-Co sites on carbon nanosheets.Based on density functional theory(DFT)calculations and LiPSs conversion catalytic ability,ZnCoN_(4)O_(2)/CN provides dual-atom sites of Zn and Co,which could facilitate Li^(+)transport and Li_(2)S diffusion,and catalyze LiPSs conversion more effectively than homonuclear bimetallic single-atom catalysts or their simple mixture and previously reported singleatom catalysts.Li-S cell with ZnCoN_(4)O_(2)/CN modified separator showed excellent rate performance(789.4 mA h g^(-1)at 5 C)and stable long cycle performance(0.05%capacity decay rate at 6C with 1000cycles,outperforming currently reported single atomic catalysts for LiPSs conversion.This work highlights the important role of metal active centers and provides a strategy for producing multifunctional dual-core single atom catalysts for high-performance Li-S cells.
文摘针对三冗余机电静压伺服系统的研制需求,设计了基于双核全可编程片上系统(All Programmable System on Chip,APSoC)技术的多总线三冗余伺服控制驱动器。通过数字总线实现子控制驱动模块之间信息共享,采用IP核技术实现硬件加速、多电机高速并行控制;通过试验验证多电机控制的同步性能和测量细节全还原技术;采用多种温度、压力传感器、过流保护电路等构建伺服系统健康网络体系,结合余度表决和故障切除逻辑搭建了三冗余控制驱动平台,对多任务的不同实时性需求分配任务等级,双核协同工作,研制的产品实物通过了系统验证。
