We experimentally obtain cylindrical vector beams（CVBs） in a passively mode-locked fiber laser based on nonlinear polarization rotation. A mode-selective coupler composed of both a single-mode fiber（SMF） and a two...We experimentally obtain cylindrical vector beams（CVBs） in a passively mode-locked fiber laser based on nonlinear polarization rotation. A mode-selective coupler composed of both a single-mode fiber（SMF） and a twomode fiber（TMF） is incorporated into the cavity to act as a mode converter from LP01 mode to LP11 mode with broad spectral bandwidth. CVBs in different mode-locked states including single-pulse, multi-pulse, and bound pulse are obtained, for the first time to our best knowledge. The ultrafast CVBs with different operation states have potential applications in many fields such as laser beam machining, nanoparticle manipulation, and so on.展开更多
In this paper, an application of voltage differencing voltage transconductance amplifier (VDVTA) in the realization of voltage-mode (VM) multi-input single output (MISO) type biquad is presented. The proposed topology...In this paper, an application of voltage differencing voltage transconductance amplifier (VDVTA) in the realization of voltage-mode (VM) multi-input single output (MISO) type biquad is presented. The proposed topology uses one VDVTA as an active element, two capacitors and a grounded resistor. The configuration realizes low pass (LP), high pass (HP), band pass (BP) and notch (BR) filters without the requirement of any matching condition. The natural frequency (w0) and bandwidth (BW) are independently controllable. The proposed circuit offers low active and passive sensitivities of w0. The operation of the proposed circuit has been verified through SPICE simulation with TSMC CMOS 0.18 μm process parameters.展开更多
提出用非线性序列二次规划(SQP,Sequen tial Q uadratic P rogramm ing)算法解决发动机性能寻优控制问题。分析了线性规划(LP,L inear P rogramm ing)算法用于发动机性能寻优的固有缺陷以及SQP算法的优点。给出了SQP算法与LP算法用于最...提出用非线性序列二次规划(SQP,Sequen tial Q uadratic P rogramm ing)算法解决发动机性能寻优控制问题。分析了线性规划(LP,L inear P rogramm ing)算法用于发动机性能寻优的固有缺陷以及SQP算法的优点。给出了SQP算法与LP算法用于最大推力模式和最小油耗模式仿真结果对比曲线。数字仿真实验的结果表明,SQP算法具有比LP算法更好的优化效果,在工程实际中有很大的应用潜力。展开更多
An all-fiberized random distributed feedback Raman fiber laser(RRFL)with LP_(11) mode output at 1134 nm has been demonstrated experimentally,where an intracavity acoustically induced fiber grating is employed for moda...An all-fiberized random distributed feedback Raman fiber laser(RRFL)with LP_(11) mode output at 1134 nm has been demonstrated experimentally,where an intracavity acoustically induced fiber grating is employed for modal switching.The maximum output power of LP_(11) mode is 93.8 W with the modal purity of 82%,calculated by numerical mode decomposition technology based on stochastic parallel-gradient descent algorithm.To our best knowledge,this is the highest output power with high purity of LP_(11) mode generated from the RRFL.This work may pave a path towards advanced fiber lasers with special temporal and spatial characteristics for applications.展开更多
基金supported by the National Science Foundation of Jiangsu Province(Nos.BK20161521 and BK20150858)the Nanjing University of Posts and Telecommunications(NUPTSF)(Nos.NY214059,NY214002,and NY215002)+2 种基金the Distinguished Professor Project of Jiangsu(No.RK002STP14001)the Six Talent Peaks Project in Jiangsu Province(No.2015-XCL-023)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Nos.SJCX17_0234 and KYCX17_0744)
文摘We experimentally obtain cylindrical vector beams（CVBs） in a passively mode-locked fiber laser based on nonlinear polarization rotation. A mode-selective coupler composed of both a single-mode fiber（SMF） and a twomode fiber（TMF） is incorporated into the cavity to act as a mode converter from LP01 mode to LP11 mode with broad spectral bandwidth. CVBs in different mode-locked states including single-pulse, multi-pulse, and bound pulse are obtained, for the first time to our best knowledge. The ultrafast CVBs with different operation states have potential applications in many fields such as laser beam machining, nanoparticle manipulation, and so on.
文摘In this paper, an application of voltage differencing voltage transconductance amplifier (VDVTA) in the realization of voltage-mode (VM) multi-input single output (MISO) type biquad is presented. The proposed topology uses one VDVTA as an active element, two capacitors and a grounded resistor. The configuration realizes low pass (LP), high pass (HP), band pass (BP) and notch (BR) filters without the requirement of any matching condition. The natural frequency (w0) and bandwidth (BW) are independently controllable. The proposed circuit offers low active and passive sensitivities of w0. The operation of the proposed circuit has been verified through SPICE simulation with TSMC CMOS 0.18 μm process parameters.
文摘提出用非线性序列二次规划(SQP,Sequen tial Q uadratic P rogramm ing)算法解决发动机性能寻优控制问题。分析了线性规划(LP,L inear P rogramm ing)算法用于发动机性能寻优的固有缺陷以及SQP算法的优点。给出了SQP算法与LP算法用于最大推力模式和最小油耗模式仿真结果对比曲线。数字仿真实验的结果表明,SQP算法具有比LP算法更好的优化效果,在工程实际中有很大的应用潜力。
基金supported by the National Natural Science Foundation of China(Nos.11704409,62061136013,and 12174445)the Open Research Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020KF03)the Special Fund for Hunan Provincial Innovative Province Building(No.2019RS3017)。
文摘An all-fiberized random distributed feedback Raman fiber laser(RRFL)with LP_(11) mode output at 1134 nm has been demonstrated experimentally,where an intracavity acoustically induced fiber grating is employed for modal switching.The maximum output power of LP_(11) mode is 93.8 W with the modal purity of 82%,calculated by numerical mode decomposition technology based on stochastic parallel-gradient descent algorithm.To our best knowledge,this is the highest output power with high purity of LP_(11) mode generated from the RRFL.This work may pave a path towards advanced fiber lasers with special temporal and spatial characteristics for applications.
