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| 1 | High-fidelity multimode fibre-based endoscopy for deep brain in vivo imaging显示文摘Progress in neuroscience relies on new techniques for investigating the complex dynamics of neuronal networks.An ongoing challenge is to achieve minimally invasive and high-resolution observations of neuronal activity in vivo inside deep brain areas.Recently introduced methods for holographic control of light propagation in complex media enable the use of a hair-thin multimode optical fibre as an ultranarrow imaging tool.Compared to endoscopes based on graded-index lenses or fibre bundles,this new approach offers a footprint reduction exceeding an order of magnitude,combined with a significant enhancement in resolution.We designed a compact and high-speed system for fluorescent imaging at the tip of a fibre,achieving a resolution of 1.18±0.04μm across a 50-μm field of view,yielding 7-kilopixel images at a rate of 3.5 frames/s.Furthermore,we demonstrate in vivo observations of cell bodies and processes of inhibitory neurons within deep layers of the visual cortex and hippocampus of anaesthetised mice.This study paves the way for modern microscopy to be applied deep inside tissues of living animal models while exerting a minimal impact on their structural and functional properties. | Sergey Turtaev Ivo T.Leite Tristan Altwegg-Boussac Janelle M.P.Pakan Nathalie L.Rochefort Tomáš Čižmár | 2018 | Light(Science & Applications)2018，7，1： | 8 |
| 2 | Urban expressway traffic state forecasting based on multimode maximum entropy model显示文摘The accurate and timely traffic state prediction has become increasingly important for the traffic participants,especially for the traffic managements. In this paper,the traffic state is described by Micro-LOS,and a direct prediction method is introduced. The development of the proposed method is based on Maximum Entropy (ME) models trained for multiple modes. In the Multimode Maximum Entropy (MME) framework,the different features like temporal and spatial features of traffic systems,regional traffic state are integrated simultaneously,and the different state behaviors based on 14 traffic modes defined by average speed according to the date-time division are also dealt with. The experiments based on the real data in Beijing expressway prove that the MME models outperforms the already existing model in both effectiveness and robustness. | SUN XiaoLiang1,2, JIA LiMin1, DONG HongHui1, QIN Yong1 & GUO Min3 1State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing 100044, China 2School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China 3Beijing Traffic Management Bureau, Beijing 100044, China | 2010 | Science China(Technological Sciences)2010，53，10： | 6 |
| 3 | Subcellular spatial resolution achieved for deep-brain imaging in vivo using a minimally invasive multimode fiber显示文摘Achieving intravital optical imaging with diffraction-limited spatial resolution of deep-brain structures represents an important step toward the goal of understanding the mammalian central nervous system1–4.Advances in wavefrontshaping methods and computational power have recently allowed for a novel approach to high-resolution imaging,utilizing deterministic light propagation through optically complex media and,of particular importance for this work,multimode optical fibers(MMFs)5–7.We report a compact and highly optimized approach for minimally invasive in vivo brain imaging applications.The volume of tissue lesion was reduced by more than 100-fold,while preserving diffraction-limited imaging performance utilizing wavefront control of light propagation through a single 50-μm-core MMF.Here,we demonstrated high-resolution fluorescence imaging of subcellular neuronal structures,dendrites and synaptic specializations,in deep-brain regions of living mice,as well as monitored stimulus-driven functional Ca2+responses.These results represent a major breakthrough in the compromise between high-resolution imaging and tissue damage,heralding new possibilities for deep-brain imaging in vivo. | Sebastian A.Vasquez-Lopez Raphaël Turcotte Vadim Koren Martin Plöschner Zahid Padamsey Martin J.Booth TomášČižmár Nigel J.Emptage | 2018 | Light(Science & Applications)2018，7，1： | 4 |
| 4 | All-fiber passively mode-locked laser using nonlinear multimode interference of step-index multimode fiber显示文摘We experimentally demonstrate for the first time, to the best of our knowledge, an all-fiber passively mode-locked laser operation based on the nonlinear multimode interference of step-index multimode fiber. Such a structure couples the light in and out of the multimode fiber via single-mode fibers, and its physical mechanisms for saturable absorption have been analyzed theoretically based on the third-order nonlinear Kerr effect of multimode fiber. Using the nonlinear multimode interference structure with 48.8 mm length step-index multimode fiber, the modulation depth has been measured to be ~5%. The passively mode-locked laser output pulses have a central wavelength of 1596.66 nm, bandwidth of 2.18 nm, pulsewidth of ~625 fs, and fundamental repetition rate of8.726 MHz. Furthermore, the influence of total cavity dispersion on the optical spectrum, pulse width, and output power is investigated systematically by adding different lengths of single-mode fiber and dispersion compensation fiber in the laser cavity. | TAO CHEN QIAOLI ZHANG YAPING ZHANG XIN LI HAIKUN ZHANG WEI XIA | 2018 | Photonics Research2018，，11： | 4 |
| 5 | Observation of controllable tightly and loosely bound solitons with an all-fiber saturable absorber显示文摘A hybrid no-core fiber(NCF)–graded index multimode fiber(GIMF) structure is used as a saturable absorber(SA)for mode-locked laser operation. Such an SA supports various types of soliton outputs. By changing the cavity parameters, not only the spatiotemporal mode-locking states with a stable single pulse but also tightly and loosely bound solitons are generated. Single 35.5 pJ solitons centered at 1568.5 nm have a 4 nm spectral full-width at half-maximum and an 818 fs temporal duration. Tightly bound soliton pairs with continuously tunable wavelength from 1567.48 nm to 1576.20 nm, featured with an ~700 fs pulse train with a separation of 2.07 ps, have been observed by stretching the NCF-GIMF structured device. Meanwhile, several different pulse separations from 37.57 ps to 56.46 ps of loosely bound solitons have also been realized. The results provide help in understanding the nonlinear dynamics in fiber lasers. | TIANYU ZHU ZHAOKUN WANG D.N.WANG FAN YANG LIUJIANG LI | 2019 | Photonics Research2019，7，1： | 4 |
| 6 | Observation of transition between multimode Q-switching and spatiotemporal mode locking显示文摘We report experimental observation of multimode Q-switching and spatiotemporal mode locking in a multimode fiber laser.A typical steady Q-switching state is achieved with a 1.88μs pulse duration,a 70.14 kHz repetition rate,and a 215.8 mW output power,corresponding to the single pulse energy of 3.08μJ.We find weak spatial filtering is essential to obtain stable Q-switched pulses,in contrast to the relatively stronger spatial filtering for spatiotemporal mode locking.Furthermore,a reversible transition process,as well as a critical bistable state,between multimode Q-switching and spatiotemporal mode locking,is achieved with specific spatial coupling and waveplates sets.We believe the results will not only contribute to understanding the complicated nonlinear dynamics in multimode,fiber-based platforms,but also benefit the development of promising high-pulse energy lasers. | Kewei Liu Xiaosheng Xiao Changxi Yang | 2021 | Photonics Research2021，9，4： | 3 |
| 7 | Compact and broadband multimode waveguide bend by shape-optimizing with transformation optics显示文摘Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabrication-complicated,which hinders their applications in future high-density multimode photonic circuits.Here we propose a compact multimode waveguide bend supporting four TE modes simply by shape-optimizing with transformation optics.The shape of the waveguide is optimized in the virtual space with gradient distribution of the refractive index,so that the scattering loss and intermode cross talk are well suppressed.After conformal mapping back into the physical space,a compact(effective radius of 17μm)multimode bending waveguide is obtained.Simulations show that the proposed multimode waveguide bend has little loss(<0.1 dB)and low cross talk(<−20 dB)throughout an ultrabroad wavelength range of 1.16–1.66μm.We also fabricated the shape-optimized multimode bending waveguide on a silicon-on-insulator wafer.At 1550 nm wavelength,the measured excess losses for the four lowest-order TE modes are less than 0.6 dB,and the intermode cross talks are all below−17 dB.Our study paves the way for realizing high-density and large-scale multimode integrated optical circuits for optical interconnect. | SHUYI LI LIFENG CAI DINGSHAN GAO JIANJI DONG JIN HOU CHUNYONG YANG SHAOPING CHEN XINLIANG ZHANG | 2020 | Photonics Research2020，8，12： | 3 |
| 8 | Complete polarization control in multimode fibers with polarization and mode coupling显示文摘Multimode optical fibers have seen increasing applications in communication,imaging,high-power lasers,and amplifiers.However,inherent imperfections and environmental perturbations cause random polarization and mode mixing,causing the output polarization states to be different from the input polarization states.This difference poses a serious issue for employing polarization-sensitive techniques to control light–matter interactions or nonlinear optical processes at the distal end of a fiber probe.Here,we demonstrate complete control of polarization states for all output channels by only manipulating the spatial wavefront of a laser beam into the fiber.Arbitrary polarization states for individual output channels are generated by wavefront shaping without constraining the input polarization.The strong coupling between the spatial and polarization degrees of freedom in a multimode fiber enables full polarization control with the spatial degrees of freedom alone;thus,wavefront shaping can transform a multimode fiber into a highly efficient reconfigurable matrix of waveplates for imaging and communication applications. | Wen Xiong Chia Wei Hsu Yaron Bromberg Jose Enrique Antonio-Lopez Rodrigo Amezcua Correa Hui Cao | 2018 | Light(Science & Applications)2018，7，1： | 3 |
| 9 | Multimode oscillation Q-switched erbium-doped fiber laser with a few-mode fiber cavity显示文摘We propose and demonstrate experimentally a multimode oscillation Q-switched erbium-doped fiber laser with a few-mode fiber cavity. The different coupling processes of reflection peaks of fiber Bragg gratings(FBGs) which act as cavity mirrors allow the different oscillating states. We obtain microsecond light pulse output states whose oscillation and output beams have different mode compositions, including high order mode. Such a structure enables the high order mode oscillation in the whole cavity with an all-fiber structure, which has potential applications in mode-division multiplexed systems and research of multimode nonlinear effect. | 韩思濛 杨康 王振洪 刘艳格 王志 | 2018 | Optoelectronics Letters2018，14，6： | 3 |
| 10 | 基于局部近邻相似度分析的多模态过程故障检测(英文)显示文摘Traditional data driven fault detection methods assume unimodal distribution of process data so that they often perform not well in chemical process with multiple operating modes. In order to monitor the multimode chemical process effectively, this paper presents a novel fault detection method based on local neighborhood similarity analysis(LNSA). In the proposed method, prior process knowledge is not required and only the multimode normal operation data are used to construct a reference dataset. For online monitoring of process state, LNSA applies moving window technique to obtain a current snapshot data window. Then neighborhood searching technique is used to acquire the corresponding local neighborhood data window from the reference dataset. Similarity analysis between snapshot and neighborhood data windows is performed, which includes the calculation of principal component analysis(PCA) similarity factor and distance similarity factor. The PCA similarity factor is to capture the change of data direction while the distance similarity factor is used for monitoring the shift of data center position. Based on these similarity factors, two monitoring statistics are built for multimode process fault detection. Finally a simulated continuous stirred tank system is used to demonstrate the effectiveness of the proposed method. The simulation results show that LNSA can detect multimode process changes effectively and performs better than traditional fault detection methods. | 邓晓刚 田学民 | 2014 | Chinese Journal of Chemical Engineering2014，22，Z1： | 3 |
| 11 | Polarization-independent multimode interference coupler with anisotropy-engineered bricked metamaterial显示文摘Many applications, including optical multiplexing, switching, and detection, call for low-cost and broadband photonic devices with polarization-independent operation. While the silicon-on-insulator platform is well positioned to fulfill most of these requirements, its strong birefringence hinders the development of polarizationagnostic devices. Here we leverage the recently proposed bricked metamaterial topology to design, for the first time, to our knowledge, a polarization-independent 2 × 2 multimode interference coupler using standard 220 nm silicon thickness. Our device can be fabricated with a single etch step and is optimized for the O-band,covering a wavelength range of 160 nm with excess loss, polarization-dependent loss, and imbalance below 1 dB and phase errors of less than 5°, as demonstrated with full three-dimensional finite-difference time-domain simulations. | Carlos Perez-Armenta Alejandro Ortega-Monux Jose Manuel Luque-Gonzalez Robert Halir Pedro J.Reyes-Iglesias Jens Schmid Pavel Cheben Inigo Molina-Fernandez J.Gonzalo Wanguemert-Perez | 2022 | Photonics Research2022，10，4： | 2 |
| 12 | A multimode digital controller IC for flyback converter with high accuracy primary-side feedback显示文摘A digital controller IC for the flyback converter with primary-side feedback is proposed. The controller is used for adapter charger or LED driver applications. To obtain high accuracy for the primary-side feedback, a digital primary-side sensing technology is adopted, which can auto-track the knee point of the primary auxiliary winding voltage. Furthermore, an internal digital compensator eliminates the need for external loop compensation components while achieving excellent line and load regulation. The controller could output both constant voltage and constant current depending on the load current. Pulse width modulation and pulse frequency modulation are used in constant voltage mode while quasi-resonant control is used in constant current mode. The digital controller is validated by using FPGA. | Jian-ping QIU Le-nian HE Yu-lin WANG | 2013 | Journal of Zhejiang University-Science C(Computers and Electronics)2013，14，8： | 2 |
| 13 | Silicon-based on-chip diplexing/triplexing technologies and devices显示文摘Wavelength-division-multiplexing(WDM) transceiver filters are one of the most essential components for realizing the fiber-to-the-home(FTTH) networks. In recent years, silicon photonics have provided a very attractive platform to build ultra-compact photonic integrated devices with CMOS-compatible processes. In this review, we focus on the recent progresses on diplexers/triplexers based on multimode interference couplers(MMI), and directional couplers(DC). The polarization-insensitive devices are also discussed. | Yaocheng SHI Jingye CHEN Hongnan XU | 2018 | Science China(Information Sciences)2018，61，8： | 2 |
| 14 | Ultra-sharp silicon multimode waveguide bends based on double free-form curves显示文摘Mode-division multiplexing(MDM)can greatly improve the capacity of information transmission.The multimode waveguide bend(MWB)with small size and high performance is of great significance for the on-chip MDM integrated system.In this paper,an MWB with high performance based on double free-form curves(DFFCs)is proposed and realized.The DFFC is a combination of a series of arcs optimized by the inverse design method.The fabrication of this MWB only needs one-step lithography and plasma etching and has a large fabrication tolerance.MWBs with effective radii of 6μm and 10μm are designed to support three modes and four modes,respectively.The proposed method gives the best overall performance considering both the effective bending radius and the transmission efficiency.The fabricated MWB with four mode channels has low excess losses and crosstalks below-21 dB in the wavelength range from 1520 to 1580 nm.It is expected that this design can play an important role in promoting the dense integration of multimode transmission systems. | SHANGSEN SUN ZHIQIANG YANG JUANLI WANG RUNSEN ZHANG FENGCHUN ZHANG NING ZHU LEI WAN ZHAOHUI LI | 2022 | Photonics Research2022，10，6： | 1 |
| 15 | Single-mode spatiotemporal soliton attractor in multimode GRIN fibers显示文摘Experimental and numerical studies of spatiotemporal femtosecond soliton propagation over up to 1 km spans of parabolic graded-index fibers reveal that initial multimode soliton pulses naturally and irreversibly evolve into a single-mode soliton. This is carried by the fundamental mode of the fiber, which acts as a dynamical attractor of the multimode system for up to the record value(for multimode fibers) of 5600 chromatic dispersion distances.This experimental evidence invalidates the use of variational approaches, which intrinsically require that the initial multimode propagation of a self-imaging soliton is indefinitely maintained. | M.ZITELLI M.FERRARO F.MANGINI S.WABNITZ | 2021 | Photonics Research2021，9，5： | 0 |
| 16 | Spatiotemporal mode decomposition of ultrashort pulses in linear and nonlinear graded-index multimode fibers显示文摘We develop a spatiotemporal mode decomposition technique to study the spatial and temporal mode power distribution of ultrashort pulses in long spans of graded-index multimode fiber,for different input laser conditions.We find that the beam mode power content in the dispersive pulse propagation regime can be described by the Bose-Einstein law,as a result of the process of power diffusion from linear and nonlinear mode coupling among nondegenerate mode groups.In the soliton regime,the output mode power distribution approaches the Rayleigh-Jeans law. | MARIO ZITELLI VINCENT COUDERC MARIO FERRARO FABIO MANGINI PEDRO PARRA-RIVAS YIFAN SUN STEFAN WABNITZ | 2023 | Photonics Research2023，11，5： | 0 |
| 17 | Electrode design for multimode suppression of aluminum nitride tuning fork resonators显示文摘This paper is focused on electrode design for piezoelectric tuning fork resonators.The relationship between the performance and electrode pattern of aluminum nitride piezoelectric tuning fork resonators vibrating in the in-plane flexural mode is investigated based on a set of resonators with different electrode lengths,widths,and ratios.Experimental and simulation results show that the electrode design impacts greatly the multimode effect induced from torsional modes but has little influence on other loss mechanisms.Optimizing the electrode design suppresses the torsional mode successfully,thereby increasing the ratio of impedance at parallel and series resonant frequencies(R_(p)/R_(s))by more than 80%and achieving a quality factor(Q)of 7753,an effective electromechanical coupling coefficient(kt_(eff)^(2))of 0.066%,and an impedance at series resonant frequency(R_(m))of 23.6 kΩ.The proposed approach shows great potential for high-performance piezoelectric resonators,which are likely to be fundamental building blocks for sensors with high sensitivity and low noise and power consumption. | Yi Yuan Qingrui Yang Haolin Li Shuai Shi Pengfei Niu Chongling Sun Bohua Liu Menglun Zhang Wei Pang | 2023 | Nanotechnology and Precision Engineering2023，6，4： | 0 |
| 18 | THEORETICAL STUDY ON COAXIAL MULTIMODE FEEDS显示文摘Using the moment method the mode ratio formulas are derived for coaxial multimode feeds. First, using the geometrical thoery of diffraction, the fields are found over an infinite plane which is one wavelength away from the feed aperture, and then, based on these fields, the radiation field of the feed is evaluated. The good agreement between the theoretical and the measured results shows the method presented is available. | 杨可忠 杨志友 高健 章日荣 | 1989 | Science China Mathematics1989，32，12： | 0 |
| 19 | Multimodal Synergistic Strategies in High School English Teaching显示文摘This paper focuses on the multimodal synergistic strategy in high school English teaching.It first briefly reviews the relevant concepts and theories of multimodality and multimodal teaching.On this basis,it employs cases from text books published by People’s Education Press to illustrate how to exert the synergistic effect of multimodal teaching to guide English teaching practice from the perspectives of the English core qualities-listening,speaking,reading,viewing,and writing.The introduction and application of multimodal theory into English teaching practice is conducive to further promoting the“student-centered”English teaching reform,and plays a positive role in the cultivation of high school students’thinking and the improvement of core literacy. | YUAN Zhi-qian | 2023 | Sino-US English Teaching2023，20，11： | 0 |
| 20 | Reconstruction performance for image transmission through multimode fibers显示文摘Due to the applications in the fields of optical communication,neuronal imaging,and medical endoscopic imaging,the study of multimode fiber(MMF)wavefront transmission is crucial for image reconstruction and wavefront generation in user terminals.State of art studies in this area focus on high-quality image reconstruction and wavefront shaping.Besides the way of imaging reconstruction,the performances of image reconstruction and wavefront shaping are also dependent on system and environment parameters.This paper numerically analyzes the influence of key factors,such as the numerical aperture(NA)of the near-end objective lens of the MMF imaging system,the charge coupled device(CCD)noise of the acquired image,and the ambient temperature at close distances.This work would help to the optimization of the MMF-based imaging system and provide a theoretical basis for potential applications in optical communication systems,neuron imaging and endoscopic diagnosis. | HU Shicheng LIN Wei LIU Haifeng ZHU Yan YANG Ling JIN Song | 2023 | Optoelectronics Letters2023，19，4： | 0 |
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