64 results on '"Hongwei Chen"'
Search Results
2. High Inductance Density Glass Embedded Inductors for 3-D Integration
- Author
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Guanyu Zhou, Libin Gao, Yuzhe Chen, Hongwei Chen, Wenlei Li, Chao Zhang, Jinxu Liu, and Jihua Zhang
- Published
- 2023
3. Modulation Strategy for Suppressing Peak Voltage Spikes of SiC-MOSFETs During ANPC Commutation
- Author
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Hongwei Chen, Sheng Ai, Ziling Nie, Fengrui Cui, and Pengfei Yuan
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General Computer Science ,General Engineering ,General Materials Science ,Electrical and Electronic Engineering - Published
- 2023
4. Reconfigurable RF Filter Based on Cascaded Microring Resonators
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Ziyang Lu, Jiachen Li, Yunhao Wu, Hongwei Chen, Sigang Yang, and Minghua Chen
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Electrical and Electronic Engineering ,Atomic and Molecular Physics, and Optics - Published
- 2023
5. Wideband Analysis and Prolongation of Surrounding TGVs Shielding Structure in 3-D ICs
- Author
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Wenlei Li, Jihua Zhang, Libin Gao, Hongwei Chen, Zhen Fang, Xingzhou Cai, Yong Li, Weicong Jia, and Huan Guo
- Published
- 2023
6. Hybrid Integrated Low Noise Optical Phase-Locked Loop Based on Self-Injection Locked Semiconductor Laser
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Liwei Tang, Sigang Yang, Hongwei Chen, and Minghua Chen
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Atomic and Molecular Physics, and Optics - Published
- 2022
7. Guest Editorial: Optical Systems and Technologies for 6G Mobile Networks
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Roberto Sabella, David Plant, Hongwei Chen, Antonella Bogoni, and Vladimir Stojanovic
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Atomic and Molecular Physics, and Optics - Published
- 2022
8. A Method for Improving Reflection Tolerance of Laser Source in Hybrid Photonic Packaged Micro-System
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Jiachen Li, Hongwei Chen, Liwei Tang, Sigang Yang, and Minghua Chen
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Coupling ,Materials science ,Laser diode ,business.industry ,Physics::Optics ,Laser ,Waveguide (optics) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Resonator ,law ,Reflection (physics) ,Optoelectronics ,Electrical and Electronic Engineering ,Photonics ,business ,Phase shift module - Abstract
In multi-chip integrated photonic micro-systems, it is important to protect the laser source from reflection because the semiconductor laser is sensitive to the back reflection induced by the roughness of the waveguide sidewall or other on-chip optical structures. In order to maintain the stable operation of the light source, an additional micro-ring resonator coupled with the laser source is design before the optical circuit which enables the laser diode to enter a self-injection locking state and improves the reflection tolerance. It is experimentally demonstrated in the hybrid system that by tuning the phase shifter and the micro-ring resonate wavelength, the distributed feedback (DFB) laser enters a self-injection locking state, resulting significant improvement of the critical reflection ratio from −18.69 dB to −4.31 dB. The method can isolate the external reflection of laser diode without using heterogeneous integration, which provides a new idea for on-chip source isolation. The parameters design of the micro-ring and the coupling method with the laser are also introduced in the letter.
- Published
- 2021
9. Dynamic Properties Analysis of a New Kind of Inter-Connected Hydro-Pneumatic Strut
- Author
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Li Ruihong, Zhao Feng, Fan Yang, Sheng Jia, Qian Wenbo, Lin Dezhao, Hongwei Chen, and Chenghong Li
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General Computer Science ,Computer science ,02 engineering and technology ,Gas chamber ,01 natural sciences ,Working condition ,Software ,sensitivity analysis ,Distortion ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,General Materials Science ,Sensitivity (control systems) ,Hydraulic machinery ,010301 acoustics ,Simulation ,Double-gas-chamber compacted Hydro-Pneumatic Struts ,business.industry ,General Engineering ,dynamic properties ,Stiffness ,TK1-9971 ,020201 artificial intelligence & image processing ,Electrical engineering. Electronics. Nuclear engineering ,medicine.symptom ,business - Abstract
The dynamic properties of one kind of Inter-Connected Hydro-Pneumatic Struts (IC HPS), which is designed based on the developed double-gas-chamber compacted Hydro-Pneumatic Struts (HPS) integrating double inner gas chambers, will be investigated in this research. Comparing with the traditional IC HPS designs based on single gas chamber compacted HPS, the proposed IC HPS can postpone the force distortion, and then increase the working envelop, provide good stiffness performance and be stable in both In-Phase and Out-of-Phase working condition. The equation of motion of the proposed IC HPS will be derived firstly. And then based on the established dynamic model, the related simulating model will be established utilizing the AMEsim software, and the validity of the established simulating model will be verified on the basis of experimental data and available literatures. The validity and performance of the proposed IC HPS will be verified and investigated through comprehensive comparison with traditional IC HPS designs. Finally, the detailed sensitivity analysis of the essential design parameter of the proposed IC HPS will be presented to illustrate the advantage of the proposed IC HPS design.
- Published
- 2021
10. Temporal Ghost Imaging by Means of Fourier Spectrum Acquisition
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Honghao Huang, Chengyang Hu, Sigang Yang, Minghua Chen, and Hongwei Chen
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lcsh:Applied optics. Photonics ,Visible light communication ,02 engineering and technology ,Iterative reconstruction ,Ghost imaging ,01 natural sciences ,Frequency-division multiplexing ,other imaging techniques ,010309 optics ,symbols.namesake ,020210 optoelectronics & photonics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Imaging systems ,lcsh:QC350-467 ,Demodulation ,Computer vision ,Electrical and Electronic Engineering ,Image sensor ,Physics ,business.industry ,Detector ,lcsh:TA1501-1820 ,Atomic and Molecular Physics, and Optics ,Fourier transform ,symbols ,Artificial intelligence ,business ,lcsh:Optics. Light - Abstract
Ghost imaging is a fascinating framework which constructs the image of an object by correlating measurements between received beams and reference beams, none of which carries the structure information of the object independently. Recently, by taking into account spacetime duality in optics, computational temporal ghost imaging has attracted attention. Here, we propose a novel Fourier temporal ghost imaging (FTGI) scheme to achieve single-shot nonreproducible temporal signals. By sinusoidal coded modulation, ghost images are obtained and recovered by applying Fourier transformation. For demonstration, non-repeating events are detected with single-shot exposure architecture. It is shown in experimental results that the peak signal-to-noise ratio (PSNR) of FTGI is significantly better (13 dB increase) than traditional temporal ghost imaging in the same condition. In addition, by using the obvious physical meaning of the Fourier spectrum, we show some potential applications of FTGI, such as frequency division multiplexing demodulation in the visible light communications.
- Published
- 2020
11. Reconfigurable Rectangular Filter With Continuously Tunable Bandwidth and Wavelength
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Jiachen Li, Sigang Yang, Hongwei Chen, and Minghua Chen
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lcsh:Applied optics. Photonics ,Integrated photonics ,Physics::Optics ,02 engineering and technology ,tunable filters ,01 natural sciences ,010309 optics ,020210 optoelectronics & photonics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Astronomical interferometer ,lcsh:QC350-467 ,Electrical and Electronic Engineering ,optical signal processing ,Physics ,Optical lattice ,Signal processing ,business.industry ,waveguide devices ,Bandwidth (signal processing) ,lcsh:TA1501-1820 ,Lattice phase equaliser ,Reconfigurability ,Atomic and Molecular Physics, and Optics ,Wavelength ,Optoelectronics ,Elliptic filter ,business ,lcsh:Optics. Light - Abstract
We propose and demonstrate a rectangular optical lattice filter with reconfigurable bandwidth and wavelength. The proposed reconfigurable rectangular lattice filter consists of three-stage cascaded ring-assisted Mach-Zehnder interferometers (RAMZIs), and each RAMZI unit serves as an approximate optical elliptical filter with optimized shape factor. The scheme and design principle are presented with the method of zero-pole theory. As a proof of concept, the proposed structure is fabricated on the Si3 N4 waveguide platform. In the experiment, the 3-dB bandwidth of the proposed filter can be continuously tuned from 14.1 GHz to 4.1 GHz, maintaining a rectangular transmission response, and the wavelength can also be continuously tuned. This reconfigurable rectangular optical lattice filter shows the potential in many practical applications for reconfigurable optical signal processing due to flexibility and reconfigurability.
- Published
- 2020
12. Quadrature Multiplexed Structured Illumination Imaging
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Chengyang Hu, Sigang Yang, Minghua Chen, and Hongwei Chen
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lcsh:Applied optics. Photonics ,Computer science ,Multispectral image ,02 engineering and technology ,01 natural sciences ,Multiplexing ,010309 optics ,0103 physical sciences ,lcsh:QC350-467 ,Computer vision ,Electrical and Electronic Engineering ,Image resolution ,Optical snapshot ,business.industry ,lcsh:TA1501-1820 ,imaging system ,021001 nanoscience & nanotechnology ,Structured illumination ,Atomic and Molecular Physics, and Optics ,Frequency spectrum ,Quadrature (astronomy) ,Proof of concept ,Computer Science::Computer Vision and Pattern Recognition ,Image sequence ,Artificial intelligence ,0210 nano-technology ,business ,lcsh:Optics. Light - Abstract
Higher dimensional optical imaging has seen remarkable growth in the past decade. As a representative method, multiplexed structured illumination (MSI) has been widely introduced for its ultra-high resolution of high-dimensional information. In this letter, an imaging framework for recovering higher dimensional image data, which terms quadrature multiplexed structured illumination (QMSI), is proposed and demonstrated. QMSI incorporates the illumination pattern spatial phase information as a new parameter into the encoding process. This strategy can double the frequency spectrum utilization without any overhead compared to MSI, which means it can double the image sequence depth or image spatial resolution. As a proof of concept, we demonstrate the performance of QMSI by experiments on multispectral imaging.
- Published
- 2020
13. Local Synchronization of Interconnected Boolean Networks With Stochastic Disturbances
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Hongwei Chen and Jinling Liang
- Subjects
Computer Networks and Communications ,Computer science ,Block matrix ,02 engineering and technology ,Topology ,Domain (mathematical analysis) ,Computer Science Applications ,Set (abstract data type) ,Artificial Intelligence ,Synchronization (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Transient (computer programming) ,Algebraic expression ,Limit set ,Software - Abstract
This paper is concerned with the local synchronization problem for the interconnected Boolean networks (BNs) without and with stochastic disturbances. For the case without stochastic disturbances, first, the limit set and the transient period of the interconnected BNs are discussed by resorting to the properties of the reachable set for the global initial states set. Second, in terms of logical submatrices of a certain Boolean vector, a compact algebraic expression is presented for the limit set of the given initial states set. Based on it, several necessary and sufficient conditions are derived assuring the local synchronization of the interconnected BNs. Subsequently, an efficient algorithm is developed to calculate the largest domain of attraction. As for the interconnected BNs with stochastic disturbances, first, mutually independent two-valued random logical variables are introduced to describe the stochastic disturbances. Then, the corresponding local synchronization criteria are also established, and the algorithm to calculate the largest domain of attraction is designed. Finally, numerical examples are employed to illustrate the effectiveness of the obtained results/ algorithms.
- Published
- 2020
14. Binarized Coherent Optical Receiver Based on Opto-Electronic Neural Network
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Xu Zhao, Hongwei Chen, Minghua Chen, Zhenming Yu, and Sigang Yang
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Artificial neural network ,business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Optical communication ,Physics::Optics ,Analog-to-digital converter ,Optical computing ,Optical polarization ,02 engineering and technology ,Multiplexing ,Atomic and Molecular Physics, and Optics ,law.invention ,020210 optoelectronics & photonics ,law ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Digital signal processing ,Phase-shift keying - Abstract
The resolution of analog to digital converter (ADC) and the power consumption of digital signal processing (DSP) are becoming the bottleneck of optical communication system. To acquire and recover signals with low resolution ADCs, we propose a binarized coherent optical receiver based on opto-electronic neural network, which consists of three layers, the broadcast layer, the optical neural layer, and the electronic neural layer. The broadcast layer that composed of Mach–Zehnder interferometers (MZIs) is to duplicate and select the input optical signal into the opto-electronic neural network. The optical neural layer is constituted by specially designed structures to map the binarized weights into optical domain, which can be integrated on silicon together with the broadcast layer. The one-bit vertical resolution ADCs act as the binarized activation after the optical neural layer. This binarized coherent optical receiver is demonstrated in simulation of 50-Gb/s single polarization (SP) QPSK system and 100-Gb/s polarization multiplexing (PDM) QPSK system. The one-bit vertical resolution ADCs can be utilized to recover the complex modulation format signal successfully. The broadcast layer and the optical neural layer can be integrated based on silicon, which could increase the calculation speed and reduce the energy consumption of the total system.
- Published
- 2020
15. Instantaneous Dynamics of a Fiber Optical Parametric Oscillator Within Its Initiating Process
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Siming Ding, Minghua Chen, Sigang Yang, Hongwei Chen, and Xu Chen
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Physics ,business.industry ,Oscillation ,Amplifier ,Noise (electronics) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optical pumping ,Wavelength ,Optics ,Fiber laser ,Optical parametric oscillator ,Spontaneous emission ,Electrical and Electronic Engineering ,business - Abstract
A fiber optical parametric oscillator (FOPO) is an effective way of generating new wavelength lasers in non-conventional wavelength bands, but the complex nature behind it is challenging for both theoretical and experimental studies. Luckily, dispersive Fourier transformation, which has been emerging in recent years, provides us with a good method of demystifying this complexity. In this letter, we capture and report, for the first time, the instantaneous dynamics of the initiating process in a fiber optical parametric oscillator. We directly observe that the initiating process experiences three stages. The FOPO fully establishes the parametric oscillation during nearly 2000 round-trips, i.e., nearly 93 $\mu \text{s}$ . In the meantime, the spectrum of the amplifier spontaneous emission noise gradually narrows down and evolves into the characteristic spectrum of the parametric oscillation. In order to start parametric oscillation, the pump power needs to exceed a certain threshold, after reaching which the power of the residual pump decreases while the signal and idle light grow. As we expect, due to the four-wave mixing effect, the signal and idle light are completely synchronous. Moreover, the stability of the oscillation is very sensitive to a slight fluctuation of the pumping pulses.
- Published
- 2019
16. Tunable Self-Injected Fabry–Perot Laser Diode Coupled to an External High-Q Si3N4 /SiO2 Microring Resonator
- Author
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Yu Li, Hongwei Chen, Minghua Chen, Sigang Yang, and Yuanjue Zhang
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Materials science ,Laser diode ,business.industry ,Optical ring resonators ,02 engineering and technology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,law.invention ,Semiconductor laser theory ,010309 optics ,Laser linewidth ,Resonator ,020210 optoelectronics & photonics ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,business ,Fabry–Pérot interferometer ,Diode - Abstract
The fast-growing fields of coherent optical communications, light detection and ranging (LIDAR), etc., have huge demand for narrow linewidth lasers. While laboratory-scale lasers have high stability with narrow linewidth down to few Hz, they are usually in large size and unable to be integrated with chip-scale optical systems. In this paper, we develop a new on-chip semiconductor laser by introducing the Vernier effect and the self-injection locking effect simultaneously between a Fabry–Perot diode laser and an external microresonator on silicon chip. The proposed laser is demonstrated with a narrow linewidth of 8 kHz and wide switchable range of 17 nm. This paper explores a new scheme to realize narrow linewidth with wide tunability for on-chip semiconductor lasers.
- Published
- 2018
17. Synchronization for the Realization-Dependent Probabilistic Boolean Networks
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Hongwei Chen, Jinling Liang, Jianlong Qiu, and Jianquan Lu
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0209 industrial biotechnology ,Theoretical computer science ,Computer Networks and Communications ,Boolean circuit ,02 engineering and technology ,Topology ,Computer Science Applications ,020901 industrial engineering & automation ,Boolean network ,Artificial Intelligence ,Probabilistic CTL ,Synchronization (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Boolean expression ,Circuit minimization for Boolean functions ,Realization (systems) ,Software ,Standard Boolean model ,Mathematics - Abstract
This paper investigates the synchronization problem for the realization-dependent probabilistic Boolean networks (PBNs) coupled unidirectionally in the drive-response configuration. The realization of the response PBN is assumed to be uniquely determined by the realization signal generated by the drive PBN at each discrete time instant. First, the drive-response PBNs are expressed in their algebraic forms based on the semitensor product method, and then, a necessary and sufficient condition is presented for the synchronization of the PBNs. Second, by resorting to a newly defined matrix operator, the reachable set from any initial state is expressed by a column vector. Consequently, an easily computable algebraic criterion is derived assuring the synchronization of the drive-response PBNs. Finally, three illustrative examples are employed to demonstrate the applicability and usefulness of the developed theoretical results.
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- 2018
18. Guest Editorial: Microwave Photonics
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José Capmany, Hongwei Chen, Jianping Yao, and Xihua Zou
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Physics ,Quantum cryptography ,business.industry ,Optoelectronics ,Laser imaging ,business ,Atomic and Molecular Physics, and Optics ,Microwave photonics - Published
- 2018
19. Efficient Wavelength-Tunable Gain-Switching and Gain-Switched Mode-Locking Operation of a Heavily Er3+-Doped ZBLAN Mid-Infrared Fiber Laser
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Kunpeng Luan, Mengmeng Tao, Jinhai Si, Yanlong Shen, Hongwei Chen, and Yishan Wang
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lcsh:Applied optics. Photonics ,Materials science ,02 engineering and technology ,Laser pumping ,01 natural sciences ,law.invention ,010309 optics ,Optics ,law ,Fiber laser ,0103 physical sciences ,lcsh:QC350-467 ,Laser power scaling ,Electrical and Electronic Engineering ,tunable ,Distributed feedback laser ,business.industry ,Lasers ,Far-infrared laser ,lcsh:TA1501-1820 ,Injection seeder ,021001 nanoscience & nanotechnology ,Laser ,pulsed ,Atomic and Molecular Physics, and Optics ,infrared and far-infrared lasers ,Optoelectronics ,0210 nano-technology ,business ,lcsh:Optics. Light ,Tunable laser ,fiber - Abstract
We report on an efficient wavelength-tunable gain-switched and gain-switched mode-locked Er3+-doped double-clad fiber laser with a linear cavity. Stable gain-switching and gain-switched mode-locking were achieved with slope efficiencies of 28.6% and 34.5% with respect to launched pump power, respectively. The gain-switched laser pulses were generated with a maximum average output power of around 110 mW, pulse width of 661.2 ns, and calculated peak power of ~16.5 W at a repetition rate of 10 kHz. At the same repetition, the gain-switched mode-locked laser pulses were generated with a maximum average output power of around 514 mW, subpulse repetition rate of ~30.7 MHz, and peak power of higher than 154 W at a repetition rate of 10 kHz when the wavelength was tuned to 2.78 μm. This is, to the best of our knowledge, the first demonstration of a gain-switched self-started mode-locked fiber laser near 3 μm.
- Published
- 2017
20. Adaptive Three-Dimensional Optimization for Optical Direct-Detection OFDM
- Author
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Shizhong Xie, Zhenming Yu, Hongwei Chen, Minghua Chen, Sigang Yang, and Yiming Lou
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Engineering ,Signal processing ,business.industry ,Orthogonal frequency-division multiplexing ,Bandwidth (signal processing) ,Spectral density ,02 engineering and technology ,Data rate ,Atomic and Molecular Physics, and Optics ,Modulation bandwidth ,020210 optoelectronics & photonics ,Modulation ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Fading ,business - Abstract
We propose an adaptive three-dimensional (3-D) optimization including bit loading, power loading, and trellis-coded modulation for optical direct-detection orthogonal frequency division multiplexing (OFDM) in the fading channel. This approach could improve the bandwidth of the various devices such as electro-optical components, digital to analog convertors (DACs), and analog to digital convertors (ADCs) effectively. We conduct experiments to verify this 3-D optimization and compare the performance with that of 2-D optimization, i.e., bit loading and power loading only. Our experimental results show that the receiver sensitivity of 3-D optimization can be improved by 2 dB at the BER of 10 –3 compared with that of 2-D optimization in the fading channel. With the simple scheme we present of realizing the optimum 3-D optimization adaptively, the data rate is improved by 32% compared with using adaptive 2-D optimization in the fading channel. With the adaptive 3-D optimization, we also transmit a 16-GHz optical OFDM signal using a 10-GHz Mach–Zehnder (MZ) intensity modulator over a 20-km standard single-mode fiber link successfully. The modulation bandwidth of the MZ modulator is improved by 60% and the data rate is improved by 40%.
- Published
- 2017
21. Synchronization of Arbitrarily Switched Boolean Networks
- Author
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Hongwei Chen, Tingwen Huang, Jinling Liang, and Jinde Cao
- Subjects
0209 industrial biotechnology ,Computer Networks and Communications ,02 engineering and technology ,Computer Science Applications ,Controllability ,Set (abstract data type) ,020901 industrial engineering & automation ,Boolean network ,Artificial Intelligence ,Control theory ,Simple (abstract algebra) ,Synchronization (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,State (computer science) ,Algebraic expression ,Boolean function ,Software ,Mathematics - Abstract
This paper investigates the complete synchronization problem for the drive-response switched Boolean networks (SBNs) under arbitrary switching signals, where the switching signals of the response SBN follow those generated by the drive SBN at each time instant. First, the definition of complete synchronization is introduced for the drive-response SBNs under arbitrary switching signals. Second, the concept of switching reachable set starting from a given initial state set is put forward. Based on it, a necessary and sufficient condition is derived for the complete synchronization of the drive-response SBNs. Last, we give a simple algebraic expression for the switching reachable set in a given number of time steps, and two computable algebraic criteria are obtained for the complete synchronization of the SBNs. A biological example is given to demonstrate the effectiveness of the obtained main results.
- Published
- 2017
22. High-Speed Compressive Microscopy of Flowing Cells Using Sinusoidal Illumination Patterns
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Yong Guo, Yuxi Wang, Shizhong Xie, Sigang Yang, Hongwei Chen, Peng Liu, Zhen Cheng, Zhenming Yu, Minghua Chen, Xiurui Zhu, and Qiang Guo
- Subjects
lcsh:Applied optics. Photonics ,Computer science ,Fast Fourier transform ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,02 engineering and technology ,Iterative reconstruction ,01 natural sciences ,Single-pixel imaging ,010309 optics ,Optics ,sinusoidal illumination patterns ,0103 physical sciences ,Microscopy ,0202 electrical engineering, electronic engineering, information engineering ,lcsh:QC350-467 ,Computer vision ,Electrical and Electronic Engineering ,Fourier spectrum acquisition ,Pixel ,business.industry ,Process (computing) ,lcsh:TA1501-1820 ,020206 networking & telecommunications ,imaging flow cytometry ,Frame rate ,Atomic and Molecular Physics, and Optics ,Orders of magnitude (time) ,Computer Science::Computer Vision and Pattern Recognition ,Artificial intelligence ,Photonics ,business ,lcsh:Optics. Light - Abstract
Single-pixel imaging (SPI) exploits the sparsity structure of natural images and enables image acquisition with far fewer measurements than the number of pixels. However, current SPI devices suffer from low imaging speed and an extremely time-consuming image reconstruction operation. Photonic time-stretch (PTS) technique is demonstrated to enable high-speed structured-illumination pattern generation, which significantly accelerates the imaging speed of conventional SPI devices. Meanwhile, to achieve fast image reconstruction, phase-shifted sinusoidal illumination patterns are used to acquire the Fourier spectrum of images and then a simple inverse fast Fourier transform (IFFT) operation is required for image reconstruction, which is quite computationally efficient. This paper presents a high-speed real-time compressive imaging system and its applications to imaging flow cytometry. Not only is a 625-kHz frame rate demonstrated, which is three orders of magnitude higher than that of a conventional SPI device, but the reconstruction process is remarkably accelerated as well, which enables our prototype system to operate in real time.
- Published
- 2017
23. CMOS-Compatible High Resolution Spatial Heterodyne Spectrometer Based on Si3N4/SiO2 Waveguide
- Author
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Hongchen Yu, Sigang Yang, Hongwei Chen, Qiang Guo, Yu Li, Minghua Chen, Le An, and Shizhong Xie
- Subjects
Heterodyne ,Waveguide (electromagnetism) ,Materials science ,Spectrometer ,business.industry ,Near-infrared spectroscopy ,Resolution (electron density) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,Wavelength ,Optics ,Planar ,0103 physical sciences ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Visible spectrum - Abstract
We experimentally demonstrated an integrated spatial heterodyne spectrometer fabricated on double-strip TriPleX waveguide technology. The TriPleX waveguide has a very low loss and tight bend so that the spectrometer realizes a high resolution of 0.023 nm across a wavelength range of 0.184 nm at 1550 nm in a small footprint of 4 mm × 8 mm. Moreover, the proposed integrated spectrometer combines the advantages of the planar lightwave circuit waveguide technology-based spectrometer and silicon-on-insulator technology-based spectrometer. The former has a very high resolution and relative high temperature stability while the latter can be implemented into a compact size based on CMOS-compatible standard technology. Besides, the wide transparency waveband of TriPleX waveguide platform makes it possible for the spatial heterodyne spectrometer to extend the working wavelength to the waveband of visible light and near infrared.
- Published
- 2016
24. Bandwidth Improvement Using Adaptive Loading Scheme in Optical Direct-Detection OFDM
- Author
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Sigang Yang, Zhenming Yu, Hongwei Chen, Shizhong Xie, and Minghua Chen
- Subjects
Orthogonal frequency-division multiplexing ,Frequency band ,Computer science ,Optical cross-connect ,Bandwidth (signal processing) ,02 engineering and technology ,Optical performance monitoring ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,020210 optoelectronics & photonics ,Modulation ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Fading ,Electrical and Electronic Engineering ,Frequency modulation - Abstract
In current metro and access optical networks, the frequency band beyond the bandwidth of the electro-optical components is always deprecated due to the fading frequency response. On the other hand, an orthogonal frequency division multiplexing (OFDM) system is managed on individual subcarrier and can adapt to the varied channel frequency response by optimally allocating different modulation formats and powers across different subcarriers. Therefore, to reuse the commercial low bandwidth components in high speed networks, we design modified OFDM signals, which are with adaptive power and bit allocation, to improve the bandwidth utilization and maximize the data rate. We successfully transmit 16-GHz optical OFDM signals over a 20-km standard single mode fiber link with a 10-GHz commercial Mach–Zehnder (MZ) intensity modulator and direct detection. Eleven modulation formats are used for bit loading and the maximum data rate can reach 88.8 Gb/s. The modulation bandwidth utilization of the MZ modulator is increased by 60%.
- Published
- 2016
25. Channel Estimation on Individual Subcarrier Using Image Processing in Optical OFDM System
- Author
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Sigang Yang, Hongwei Chen, Shizhong Xie, Zhenming Yu, Yiming Lou, and Minghua Chen
- Subjects
Computer science ,Orthogonal frequency-division multiplexing ,Clock rate ,Image processing ,Constellation diagram ,02 engineering and technology ,Optical modulation amplitude ,Optical performance monitoring ,Atomic and Molecular Physics, and Optics ,Subcarrier ,Electronic, Optical and Magnetic Materials ,020210 optoelectronics & photonics ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,Quadrature amplitude modulation - Abstract
In an optical orthogonal frequency division multiplexing (OFDM) system, channel impairments, such as residual chromatic dispersion, residual synchronization error, and clock frequency offset, induce phase shifts over subcarriers. We propose a method of using image processing for phase channel estimation with negligible overhead, which is applicable to various subcarrier modulation formats. We conduct the experiment of 32-, 40-, and 48-Gbit/s direct detection optical OFDM with 16QAM, 32QAM, and 64QAM subcarrier modulation and simulation of 112-Gb/s coherent optical OFDM to verify this method and compare the results with those of the conventional method. Then, we investigate the effects of the numbers of required test phases and OFDM symbols with experimental data. We also present an approach of removing the inner part of constellation points to reduce the complexity.
- Published
- 2016
26. Stable Mode-Locked Nanosecond Chirp-Free Pulse Generation With Ultra-Narrow Bandwidth
- Author
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Shizhong Xie, Chen Jin, Sigang Yang, Hongwei Chen, Minghua Chen, and Xiaojian Wang
- Subjects
Mode volume ,Materials science ,business.industry ,Physics::Optics ,02 engineering and technology ,Nanosecond ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,020210 optoelectronics & photonics ,Optics ,Fiber Bragg grating ,Fiber laser ,0103 physical sciences ,Spectral width ,0202 electrical engineering, electronic engineering, information engineering ,Chirp ,Physics::Accelerator Physics ,Dispersion-shifted fiber ,Physics::Atomic Physics ,Electrical and Electronic Engineering ,business ,Bandwidth-limited pulse - Abstract
A stable nanosecond chirp-free pulse generation with ultra-narrow bandwidth is established from a passively mode-locked erbium-doped fiber laser with a homemade fiber Bragg grating as the intra-cavity filter and careful intra-cavity dispersion management introduced. The laser generates nearly chirp-free pulse that is close to the Fourier transform-limited condition. The measured pulsewidth is 2 ns and the spectral width is only 192 MHz. The measured time jitter is below 1%. The pulse repetition rate is 982 kHz, which reveals there are only 195 oscillating longitudinal modes. This is the longest duration of single stable chirp-free pulse in passively continuous-wave mode-locked fiber lasers to our best knowledge.
- Published
- 2016
27. All-Optical OFDM Demultiplexer Based on an Integrated Silicon-on-Insulator Technique
- Author
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Minghua Chen, Hongwei Chen, Sigang Yang, Hongchen Yu, Shizhong Xie, and Hai Yu
- Subjects
lcsh:Applied optics. Photonics ,Demultiplexer ,Materials science ,Orthogonal frequency-division multiplexing ,02 engineering and technology ,01 natural sciences ,Waveguide (optics) ,Multiplexing ,010309 optics ,020210 optoelectronics & photonics ,Optics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,lcsh:QC350-467 ,Electrical and Electronic Engineering ,Optical filter ,wavelength filtering devices ,Optical communications ,business.industry ,lcsh:TA1501-1820 ,Atomic and Molecular Physics, and Optics ,integrated optics devices ,Transmission (telecommunications) ,Modulation ,Bit error rate ,Optoelectronics ,business ,lcsh:Optics. Light - Abstract
An all-optical orthogonal frequency-division multiplexing (OFDM) demultiplexer based on silicon-on-insulator (SOI) waveguide technology is proposed and experimentally demonstrated. Such an integrated structure performing a discrete Fourier transform (DFT) not only has the advantages of a smaller volume and better stability but can also handle more optical subcarriers by increasing the number of the cascaded Mach-Zehnder interferometer (MZI) stages. An SOI-based eight-channel OFDM demultiplexer has been successfully fabricated with a free spectrum range (FSR) of approximately 64 GHz. Eight-subcarrier optical OFDM signals with non-return-to-zero (NRZ) formats are successfully detected by the proposed demultiplexer after a 30-km fiber-link transmission. The total modulation speed is 64 Gbaud, and the bit error rate (BER) performance of each subcarrier is also measured.
- Published
- 2016
28. All-Optical Full-Band RF Receiver Based on an Integrated Ultra-High-Q Bandpass Filter
- Author
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Shizhong Xie, Hongwei Chen, Sigang Yang, Rene Heideman, Marcel Hoekman, Qiang Guo, Minghua Chen, Hongchen Yu, Richard Mateman, and Arne Leinse
- Subjects
Physics ,Waveguide filter ,Spurious-free dynamic range ,business.industry ,Bandwidth (signal processing) ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,010309 optics ,020210 optoelectronics & photonics ,Band-pass filter ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Prototype filter ,Radio frequency ,Center frequency ,Optical filter ,business - Abstract
Ultra-broadband radiofrequency (RF) receivers are required in higher frequency-band wireless communications, radar communications or multi-band applications in radio telescopes. Such ultra-broadband receivers are inherently difficult to establish with electronics because of limits in the bandwidth of the devices. Photonic means of RF photonic receivers/frontends can overcome the bandwidth limitation in electrical receivers. One aspect that should be considered is the precise signal processing in the optical domain. Here, a full-band (from the L-band to the W-band) all-optical RF receiver based on the Si3N4 microring filter is proposed and experimentally demonstrated. The resolution and processing range of the filter are lower than 420 MHz and larger than 112.9 GHz (FSR larger than 225.78 GHz), respectively, and the out-band suppression of this filter is greater than 40 dB. The center frequency of the filter can be altered for more than one FSR by tuning the phase-shifter on top of the ring. The performance of the full-band all-optical RF-receiver has been discussed, and the spurious free dynamic range of the receiver from the L-band to the Ka-band (limited by the bandwidth of the modulator in our experiment) has been measured to be larger than 111.6 dB·Hz2/3.
- Published
- 2016
29. Ultrafast Three-Dimensional Surface Imaging Based on Short-Time Fourier Transform
- Author
-
Hongwei Chen, Jianping Yao, Fangjian Xing, and Shizhong Xie
- Subjects
Beam diameter ,Materials science ,business.industry ,Short-time Fourier transform ,Pulse sequence ,Interference (wave propagation) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,Fourier transform ,Optics ,Frequency domain ,symbols ,Time domain ,Electrical and Electronic Engineering ,business ,Ultrashort pulse - Abstract
A novel approach to achieving ultrafast three-dimensional (3-D) imaging based on space-to-wavelength-to-time mapping and short-time Fourier transform (STFT) is proposed and experimentally demonstrated. The fundamental concept to achieve 3-D imaging is to encode the depth information of a sample by interfering two delayed pulses that are reflected from the surface of the sample and an additional reference plane on the top of the sample. The interference pattern that contains the depth information in the frequency domain is converted into the time domain based on dispersive Fourier transform and then analyzed based on STFT. Thus, ultrafast 3-D imaging is achieved. The proposed approach is experimentally evaluated. The imaging of a sample with a depth of 1.5 mm using an ultrafast pulse laser source with a beam width of $\sim 2$ mm at a repetition rate of 48.8 MHz is demonstrated.
- Published
- 2015
30. Photonic Downconversion and Linearization of Microwave Signals from the <tex-math notation='LaTeX'>$X$ </tex-math>- to <tex-math notation='LaTeX'>$K\!$ </tex-math>-Band
- Author
-
Hongwei Chen, Shizhong Xie, Minghua Chen, Hongchen Yu, Sigang Yang, Ran Shi, and Pengxiao Li
- Subjects
Physics ,Spurious-free dynamic range ,business.industry ,Local oscillator ,Optical cross-connect ,Optical modulation amplitude ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Optical transistor ,Radio frequency ,Electrical and Electronic Engineering ,Photonics ,business ,Intermodulation - Abstract
A linearized photonic radio frequency (RF)-to-intermediate frequency (IF) conversion system is proposed and experimentally demonstrated based on balanced detection and digital signal postcompensation. The optical carrier suppression and remodulation scheme is employed to significantly reduce the local oscillator frequency requirements and common mode optical phase noises. Photonic IF downconversion is enabled by using a reconfigurable multiport optical processor and balanced coherent detection of the spectrally separated lower and upper first-order sidebands of the phase modulated signals. Moreover, the digital linearization technique is used to suppress the third-order intermodulation components by more than 21 dB and an improvement of the spurious free dynamic range as large as 7 dB for RF signals ranging from 8–20 GHz is also achieved.
- Published
- 2015
31. Si 3N 4-Based Integrated Optical Analog Signal Processor and Its Application in RF Photonic Frontend
- Author
-
Qiang Guo, M. Hoekman, Hongchen Yu, Shizhong Xie, Arne Leinse, Richard Mateman, Sigang Yang, Hongwei Chen, Rene Heideman, and Minghua Chen
- Subjects
Digital signal processor ,Signal processing ,Computer science ,business.industry ,Filter (signal processing) ,Atomic and Molecular Physics, and Optics ,Effective number of bits ,Analog signal ,Optics ,Electronic engineering ,Radio frequency ,Electrical and Electronic Engineering ,Photonics ,business ,Digital signal processing - Abstract
Digital signal processing has achieved great success in the field of signal processing over the past several decades. However, as the bandwidth requirement increases, the power consumption and effective number of bits (ENOB) of the analog-to-digital convertor (ADC) have become bottlenecks. One solution is returning to analog and applying microwave photonic technologies, which shows potential for multiband signal processing. In this paper, a programmable integrated analog photonic signal processor based on cascaded Mach-Zehnder interferometers (MZIs) and a channelized filter has been proposed. Different shapes of the signal processor can be acquired for different applications. The highest processing resolution is 143 MHz, and the processing range of the signal processor can be higher than 112.5 GHz. An application of the signal processor for the signal extraction in a radio frequency (RF) photonic frontend operating from L-band to K-band is presented.
- Published
- 2015
32. Ultra High-Repetition-Rate Pulse Sources Based on Cascaded Four Wave Mixing in EYDF
- Author
-
Hongwei Chen, Shizhong Xie, Sigang Yang, Minghua Chen, and Zhaohui Wu
- Subjects
Range (particle radiation) ,Materials science ,business.industry ,Terahertz radiation ,Phase (waves) ,Physics::Optics ,02 engineering and technology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Pulse (physics) ,Wavelength ,Four-wave mixing ,020210 optoelectronics & photonics ,Optics ,0202 electrical engineering, electronic engineering, information engineering ,Waveform ,Fiber ,Electrical and Electronic Engineering ,business - Abstract
We report all-fiber tunable ultrahigh-repetition-rate sub-picosecond pulse sources around 1550 nm. The sources are based on cascaded four wave mixing in an erbium-ytterbium co-doped fiber without extra nonlinear fiber. They are seeded by a spacing-tunable phase conjugated dual-wavelength parametric light source centered at 1550 nm. The repetition rate of the pulse sources can be tuned continuously in the range of 0.75-2.75 THz by adjusting the wavelength spacing of the dual-wavelength light source. We use auto-correlator to measure the waveform of the pulses. The duration of the pulses is about 100 fs.
- Published
- 2017
33. Time-Interleaved 20-GHz Modulated Wideband Converter Based on Random Optical Sampling
- Author
-
Sigang Yang, Hongwei Chen, Shizhong Xie, Qiang Guo, Yunhua Liang, and Minghua Chen
- Subjects
Physics ,business.industry ,Bandwidth (signal processing) ,Ranging ,Pseudorandom binary sequence ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Compressed sensing ,Optics ,Electronic engineering ,Pulse wave ,Radio frequency ,Electrical and Electronic Engineering ,Wideband ,Photonics ,business ,Computer Science::Information Theory - Abstract
In this letter, time-interleaved multiwavelength pseudorandom binary sequence (PRBS) optical pulses are utilized to significantly increase the instantaneous bandwidth of the modulated wideband converter (MWC). A four-channel MWC with a bandwidth of 20 GHz is proposed for the first time, where four-wavelength optical pulse trains modulated by a 10.16-Gb/s PRBS signal are interleaved temporally after going through four sections of fibers with different lengths in parallel. The flat and ultrawide spectrum of the PRBS-modulated pulse train guarantees a uniform SNR and recovery probability. Sparse radio frequency signals ranging from 0.5 to 20 GHz are reconstructed faithfully from four-channel samples with only 360-MHz bandwidth.
- Published
- 2015
34. Ultrafast Surface Imaging With an Increased Spatial Resolution Based on Polarization-Division Multiplexing
- Author
-
Jianping Yao, Hongwei Chen, Shizhong Xie, and Fangjian Xing
- Subjects
Physics ,business.industry ,Image quality ,02 engineering and technology ,Polarization-division multiplexing ,Polarization (waves) ,Frame rate ,01 natural sciences ,Multiplexing ,Atomic and Molecular Physics, and Optics ,010309 optics ,020210 optoelectronics & photonics ,Optics ,Optical imaging ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,business ,Image resolution ,Ultrashort pulse - Abstract
Optical time stretch has been employed for ultrafast optical imaging based on space-to-wavelength-to-time mapping. However, temporal overlap between two adjacent time-stretched pulses is a disadvantageous factor that limits the spatial resolution, or the frame rate has to be reduced by reducing the pulse repetition rate to avoid the temporal overlap. To increase the spatial resolution without reducing the frame rate, we propose a novel technique based on polarization-division multiplexing, using a polarization modulator to generate two polarization interleaved pulse trains. Since two adjacent optical pulses are orthogonally polarized, the spacing between two adjacent pulses for one polarization direction is doubled, and the spatial resolution is doubled by using a dispersive element with two times the dispersion. The proposed approach is experimentally evaluated. An imaging system with an increased spatial resolution is demonstrated.
- Published
- 2015
35. Photonics-Assisted Serial Channelized Radio-Frequency Measurement System With Nyquist-Bandwidth Detection
- Author
-
Sigang Yang, Shizhong Xie, Ying Yu, Minghua Chen, Cheng Lei, Hongwei Chen, and Ruiyue Li
- Subjects
lcsh:Applied optics. Photonics ,Physics ,Receiver Bandwidth ,business.industry ,Bandwidth (signal processing) ,Detector ,lcsh:TA1501-1820 ,Atomic and Molecular Physics, and Optics ,Optics ,lcsh:QC350-467 ,Nyquist frequency ,Time domain ,Radio frequency ,Electrical and Electronic Engineering ,Photonics ,business ,Frequency modulation ,lcsh:Optics. Light ,Computer Science::Information Theory - Abstract
Based on serial channelization and coherent detection, a radio-frequency (RF) measurement scheme with a Nyquist-bandwidth detector is proposed and experimentally demonstrated. With a wavelength scanning structure, multiple RF channels serial in the time domain are implemented. A coherent receiving module based on an optical hybrid and balanced photodetectors (BPDs) is constructed to reduce the receiver bandwidth and the bandwidth of the follow-up electronic devices. In this paper, a six-channel 3-GHz-spacing channelizer, with 18-GHz receiving bandwidth and 1.5-GHz BPD, is demonstrated. In addition, multifrequency signals and a linear frequency modulation signal with the slope of 4.53 MHz/ $\mu\hbox{s}$ are tested.
- Published
- 2014
36. Photonic Crystal Fiber Based Wavelength-Tunable Optical Parametric Amplifier and Picosecond Pulse Generation
- Author
-
Sigang Yang, Hongwei Chen, Wei Chen, Lei Zhang, Xiaojian Wang, Wenyong Luo, Minghua Chen, Doudou Gou, and Shizhong Xie
- Subjects
lcsh:Applied optics. Photonics ,Optical amplifier ,Materials science ,business.industry ,Physics::Optics ,lcsh:TA1501-1820 ,Microstructured optical fiber ,Optical parametric amplifier ,Atomic and Molecular Physics, and Optics ,Optics ,Zero-dispersion wavelength ,lcsh:QC350-467 ,Optoelectronics ,Dispersion-shifted fiber ,Electrical and Electronic Engineering ,business ,Plastic optical fiber ,lcsh:Optics. Light ,Photonic-crystal fiber ,Photonic crystal - Abstract
We report a fiber optical parametric amplifier (FOPA) based on a photonic crystal fiber (PCF) with optimized dispersion and nonlinear properties pumped by a mode-locked ytterbium-doped fiber laser. Wavelength-tunable parametric gain bands can be obtained by adjusting the pump wavelength from the anomalous to the normal dispersion regime. By utilizing the PCF-based FOPA, weak signals located in the parametric gain bands can be amplified. Wavelength-tunable picosecond pulses can be generated at the signal and idler wavelengths. A 58-dB maximum gain and a wide gain bandwidth from 999 to 1139 nm have been achieved by pumping near the zero-dispersion wavelength. When the FOPA is pumped at 1062.5 nm in the normal dispersion regime of the PCF, the 974-nm weak continuous-wave signal is significantly amplified, and the idler pulse is generated at 1168 nm.
- Published
- 2014
37. All-Fiber-Integrated High-Power Supercontinuum Sources Based on Multi-Core Photonic Crystal Fibers
- Author
-
Qisheng Lu, Tong Liu, Jinyan Li, Xuanfeng Zhou, Hongwei Chen, Huifeng Wei, Zilun Chen, Peiguang Yan, Jing Hou, and Sheng-Ping Chen
- Subjects
Materials science ,business.industry ,Polarization-maintaining optical fiber ,Graded-index fiber ,Atomic and Molecular Physics, and Optics ,Supercontinuum ,Optics ,Double-clad fiber ,Zero-dispersion wavelength ,Fiber laser ,Optoelectronics ,Dispersion-shifted fiber ,Electrical and Electronic Engineering ,business ,Photonic-crystal fiber - Abstract
The obstacles of power scaling the supercontinuum (SC) source based on single-core photonic crystal fiber (PCF) are analyzed. The combination of high-power fiber lasers and multi-core PCFs would be a feasible method to obtain an all-fiber-integrated high-power broadband SC source (covering visible range). In this paper, we present a comprehensive study of high-power SC generation in multi-core PCFs. Comparative experiments are performed by using a high-power pulse-repetition-rate-tunable picosecond fiber laser to pump two kinds of home-made seven-core PCFs. The influences of PCF structure (fiber dispersion property) and pulse repetition rate (pulse peak power) on the SC generation in multi-core PCFs are investigated in detail. When the picosecond fiber laser at a pulse repetition rate of 1.9 GHz is adopted as the pump, 116 W SC spanning from 800 to 1700 nm is generated in 1# seven-core PCF. Also 64 W visible SC spanning at least 500-1700 nm is demonstrated in 2# seven-core PCF at a pump pulse repetition rate of 480 MHz. The potential of extending the spectral range and scaling the output power for the SC source based on multi-core PCFs are analyzed and discussed.
- Published
- 2014
38. An Efficient Integral Equation/Modified Surface Integration Method for Analysis of Antenna-Radome Structures in Receiving Mode
- Author
-
Binbin Wang, Jinbo Liu, Guoqiang Zhao, Hongwei Chen, Chuanfang Zhang, and Mang He
- Subjects
Surface (mathematics) ,Mathematical optimization ,Directional antenna ,Computer science ,Mode (statistics) ,Volume (computing) ,Radome ,Integral equation ,law.invention ,law ,Electrical and Electronic Engineering ,Antenna (radio) ,Multipole expansion ,Algorithm - Abstract
An efficient approach that combines the coupled volume surface integral equation (VSIE) accelerated by multilevel fast multipole algorithm (MLFMA) and the modified surface integration (MSI) method is proposed to analyze the antenna-radome structures (ARS) in receiving mode. The hybrid method not only reduces the computational time and memory requirement as compared to the purely full-wave solutions, but also more importantly overcomes the difficulties in conventional high-frequency approximate methods for analyzing the properties of the radome-enclosed receiving antennas or arrays. Numerical results are shown to illustrate the validity, efficiency, and accuracy of the proposed method.
- Published
- 2014
39. Large-Tap Microwave Photonics Filter Based on Recirculating Frequency Shifting Loop
- Author
-
Sigang Yang, Shizhong Xie, Jingjing Wang, Minghua Chen, and Hongwei Chen
- Subjects
Physics ,Waveguide filter ,business.industry ,Low-pass filter ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Band-pass filter ,Filter (video) ,Prototype filter ,Electrical and Electronic Engineering ,Center frequency ,Optical filter ,business ,Electronic filter - Abstract
A novel large-tap and tunable microwave photonics (MWPs) filter based on a recirculating frequency shifting loop has been proposed and experimentally demonstrated. To improve the Q -factor value of the MWP filter, we used a simple recirculation loop to economically generate a large-tone optical frequency comb in this scheme. In addition, the cumulative effect in loop structure, which affects the characteristics of the generated taps significantly, is analyzed to predict the performance of the proposed filter. In experiments, we realized a 70-tap filter at 4.5 GHz with the Q -factor value exceeding 70. Also, a filter with center frequency tunable from 1 to 8 GHz is demonstrated.
- Published
- 2014
40. Picosecond Photonic Crystal Fiber-Based Doubly Resonant Optical Parametric Oscillator
- Author
-
Minghua Chen, Lei Zhang, Hongwei Chen, Shizhong Xie, Xiaojian Wang, Sigang Yang, Doudou Gou, and Pengxiao Li
- Subjects
Optical amplifier ,Materials science ,business.industry ,Physics::Optics ,Optical parametric amplifier ,Signal ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Wavelength ,Optics ,Picosecond ,Optical parametric oscillator ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Photonic crystal ,Photonic-crystal fiber - Abstract
A picosecond photonic crystal fiber-based doubly resonant optical parametric oscillator is demonstrated. A four-wavelength oscillator can be obtained by selecting a wavelength in signal cavity and a wavelength in idler cavity phase-mismatched with the one in signal cavity to oscillate simultaneously. The output light beams are improved significantly when the signal wavelength and the phase-matched idler wavelength are selected to oscillate simultaneously in the two cavities. In particular, the peak intensities of the output signal and idler are increased by 2.53-5.77 dB, the 3-dB bandwidths of the signal and idler are narrowed by 0.05-2.98 nm, and the pump-to-idler conversion efficiencies are improved by 2.2-3.8 times.
- Published
- 2014
41. Generation of Versatile Waveforms From CW Light Using a Dual-Drive Mach-Zehnder Modulator and Employing Chromatic Dispersion
- Author
-
Naoya Wada, Nobuyuki Kataoka, Hongwei Chen, Xu Wang, Zhensen Gao, and Bo Dai
- Subjects
Physics ,business.industry ,Electro-optic modulator ,Hardware_PERFORMANCEANDRELIABILITY ,Sawtooth wave ,Instantaneous phase ,Atomic and Molecular Physics, and Optics ,Pulse (physics) ,symbols.namesake ,Fourier transform ,Optics ,Computer Science::Sound ,Dispersion (optics) ,Hardware_INTEGRATEDCIRCUITS ,symbols ,Waveform ,Time domain ,business ,Hardware_LOGICDESIGN - Abstract
In this paper, we analyze waveform generation using a single-stage dual-drive Mach-Zehnder modulator and a dispersive fiber. We derive a mathematical expression for the waveform generation process in the time domain and use this to propose a waveform generation algorithm. Furthermore, versatile waveforms, such as short pulse, trapezoidal, triangular and sawtooth waveforms and doublet pulse, are theoretically generated under different combinations of the four variables. The generated waveforms are analyzed in terms of the gradient and the instantaneous frequency. Finally, the waveform generation is experimentally demonstrated at the repetition rate of 10 GHz.
- Published
- 2013
42. All-Optical Sampling Orthogonal Frequency-Division Multiplexing Scheme for High-Speed Transmission System
- Author
-
Hongwei Chen, Shizhong Xie, and Minghua Chen
- Subjects
Optical fiber ,business.industry ,Orthogonal frequency-division multiplexing ,Spectral efficiency ,Multiplexing ,Atomic and Molecular Physics, and Optics ,law.invention ,Frequency-division multiplexing ,Optics ,Fiber Bragg grating ,law ,business ,Phase modulation ,Phase-shift keying ,Mathematics - Abstract
A novel high spectral efficiency all-optical sampling orthogonal frequency-division multiplexing (AOS-OFDM) scheme with optical cyclic postfixes (OCPs) inserted is proposed. Ultrashort pulses are used as optical samples and processed by all optical discrete Fourier transformers based on fiber Bragg gratings (FBGs) technique. This scheme includes five subcarrier channels with 20 Gb/s differential quadrature phase-shift keying (DQPSK) modulation of each channel. So, the total bit rate is 100 Gb/s. The spectral efficiency is higher than 1.4. Furthermore, with the help of OCPs, the dispersion tolerance of this 100 Gb/s AOS-OFDM system increases to more than 300 ps/nm, which is much higher than a traditional 100 Gb/s DQPSK system.
- Published
- 2009
43. Optical Code Label Stripping based on SOA-MZI in Optical Packet Switching Networks
- Author
-
Hongwei Chen, Ming Xin, Minghua Chen, and Shizhong Xie
- Subjects
Packet switching ,Tolerance analysis ,Computer science ,computer.internet_protocol ,Electronic engineering ,Optical communication ,Contrast ratio ,Multiprotocol Label Switching ,Telecommunications network ,Optical switch ,computer ,Atomic and Molecular Physics, and Optics ,Synchronization - Abstract
As an alternative to label swapping, an all-optical label stripping scheme based on SOA-MZI is proposed. The stripping process is self-controlled without any synchronization process. Simulation results show that high-quality stripping can be achieved, with no more than 0.09 dB of power fluctuation and 0.05 dB of phase fluctuation in stripped and remaining label. A power contrast ratio of 28 dB between the remaining and residual stripped label, and 30-dB signal-to-noise ratio can be reached, respectively. Parameters tolerance analysis shows that the stripping performance deteriorates little when considering the devices' imperfection in practice. The multihop simulation results also show that our scheme is applicable to large-scale optical packet switching networks.
- Published
- 2009
44. High-Spectral-Purity Millimeter-Wave Signal Optical Generation
- Author
-
Jian Zhang, Minghua Chen, Hongwei Chen, Shizhong Xie, and Tianliang Wang
- Subjects
Physics ,Optical amplifier ,Physics::Instrumentation and Detectors ,business.industry ,Physics::Optics ,Optical modulation amplitude ,Signal ,Atomic and Molecular Physics, and Optics ,Signal transition ,Optics ,Analog signal ,business ,Phase modulation ,Intensity modulation ,Spectral purity - Abstract
In this paper, novel approaches for millimeter-wave signal generation using double-sideband suppressed-carrier modulation and four-wave mixing are proposed and demonstrated. The millimeter-wave signal is generated at a photodetector by beating the optical sidebands, which are gained from intensity modulation and after semiconductor optical amplifiers. In the proposed methods, the generated millimeter-wave signal has a frequency that is double, quadruple, sextuple, 12 times, or even 18 times higher than the microwave drive signal. And, it has quite good gain flatness with extremely high-spectral-purity and stability. The phase noise performance of the generated millimeter wave is investigated. The 3-dB linewidth of the millimeter wave has no broadening after propagating through 20-km standard single-mode fiber.
- Published
- 2009
45. Methods for Ultra-Wideband Pulse Generation Based on Optical Cross-Polarization Modulation
- Author
-
Shizhong Xie, Mo Li, Minghua Chen, Tianliang Wang, and Hongwei Chen
- Subjects
Physics ,Femtosecond pulse shaping ,Optical amplifier ,Continuous phase modulation ,Optics ,business.industry ,Pulse wave ,Optical polarization ,Photonics ,business ,Ultrashort pulse ,Atomic and Molecular Physics, and Optics ,Bandwidth-limited pulse - Abstract
Optical methods for different type ultra-wideband (UWB) pulse generation based on cross-polarization modulation (CPM) are proposed and demonstrated in this paper. Two polarity-reverse pulses can be obtained by CPM and birefringence time delay to form a monocycle pulse. A semiconductor optical amplifier (SOA) is placed after the monocycle pulse process for doublet pulse generation. These two kinds of pulses can be employed in single-band impulse radio UWB (IR-UWB) systems. Two kinds of multi-band UWB pulses can be generated based on monocycle pulse train with proper apodization profiles, realized by hybrid photonic microwave filter and synchronous polarization modulation respectively. Experimental results show that these pulses can be used in multi-band UWB (MB-UWB) over fiber systems.
- Published
- 2008
46. Vestigial-sideband payload for high-speed all-optical label-switching network
- Author
-
Shizhong Xie, Hongwei Chen, Bingkun Zhou, and Minghua Chen
- Subjects
Engineering ,Interference (communication) ,Sideband ,business.industry ,Label switching ,Payload (computing) ,Bit error rate ,Electronic engineering ,business ,Optical filter ,Noise (electronics) ,Optical switch ,Atomic and Molecular Physics, and Optics - Abstract
A novel vestigial-sideband (VSB) payload scheme is proposed for high-speed all-optical label-switching (AOLS) networks. The combination and separation of the VSB payload and the optical label is experimentally demonstrated, and the influences of the power-split ratio, time-delay interference, interferometric noise (IN), and wavelength difference between the payload and the label are analyzed. Simulation and experiment results show that this VSB payload scheme can highly reduce the channel bandwidth and it is easy to realize by using optical filters, so it is a potential technique to be used in optical networks with bit rate of 40 Gb/s.
- Published
- 2005
47. AlGaN/GaN MISHEMTs With High-$\kappa \ \hbox{LaLuO}_{3}$ Gate Dielectric
- Author
-
Chunhua Zhou, Shu Yang, Sen Huang, M. Schnee, Qing-Tai Zhao, Hongwei Chen, Kevin J. Chen, Qi Zhou, and J. Schubert
- Subjects
Materials science ,business.industry ,Transconductance ,Gate dielectric ,Gallium nitride ,Dielectric ,Subthreshold slope ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,Planar process ,Electrical and Electronic Engineering ,Thin film ,business ,MISFET - Abstract
A high-κ LaLuO3 (LLO) thin film is successfully incorporated into AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMTs) as the gate dielectric. The LLO-AlGaN/GaN MISHEMTs fabricated with a planar process exhibit a high ION/IOFF of 109, a maximum drain current of 820 mA/mm at VGS = 3 V, a peak transconductance (Gm) of ~ 192 mS/mm, and a steep subthreshold slope (SS) of ~ 73 mV/dec.
- Published
- 2012
48. Schottky Source/Drain InAlN/AlN/GaN MISHEMT With Enhanced Breakdown Voltage
- Author
-
Zhihong Feng, Chunhua Zhou, Kevin J. Chen, Shujun Cai, Qi Zhou, and Hongwei Chen
- Subjects
Materials science ,business.industry ,Transconductance ,Transistor ,Wide-bandgap semiconductor ,Schottky diode ,Gallium nitride ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Logic gate ,Optoelectronics ,Breakdown voltage ,Electrical and Electronic Engineering ,business ,Ohmic contact - Abstract
In this letter, we present the deployment of Schottky source/drain (SSD) in InAlN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMTs) for off-state breakdown voltage improvement. The improved breakdown voltage relies on the suppression of electron injection into the buffer under the Schottky source contact. A VBD of 460 V is obtained in an SSD MISHEMT with an LGD = 10nμm, at a 170% improvement compared with that of the control MISHEMT featuring ohmic source/drain. Despite the SSD contacts, an SSD MISHEMT with a gate length of 1 μm exhibits a respectable drain current density of 416 mA/mm and a transconductance of 113 mS/mm.
- Published
- 2012
49. Gate-Induced Schottky Barrier Lowering Effect in AlGaN/GaN Metal–2DEG Tunnel Junction Field Effect Transistor
- Author
-
Kevin J. Chen, Hongwei Chen, Qi Zhou, Chunhua Zhou, and Li Yuan
- Subjects
Materials science ,business.industry ,Schottky barrier ,Transistor ,Wide-bandgap semiconductor ,Gallium nitride ,Electronic, Optical and Magnetic Materials ,law.invention ,Metal ,chemistry.chemical_compound ,chemistry ,Tunnel junction ,law ,Logic gate ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,Field-effect transistor ,Electrical and Electronic Engineering ,business - Abstract
The Schottky-source forward current-voltage characteristics were measured and analyzed in a recently reported AlGaN/GaN metal-2-D-electron-gas tunnel junction field-effect transistor (FET) (TJ-FET) in order to characterize the effective Schottky barrier height (SBH) and its gate bias dependence. The SBHs were extracted and found to be gate bias dependent, varying from 0.57 eV at VGS = -0.5 V to 0.3 eV at VGS = 1 V. This gate-induced Schottky barrier lowering (SBL) effect is explained by the image-charge effect. A 2-D device simulation is carried out to analyze the SBL effect and is shown to be in good agreement with the experiment results. The larger SBH at lower gate voltage enables off -state blocking, while the lower SBH at higher gate voltage leads to high on -state current driving capability in the AlGaN/GaN TJ-FETs.
- Published
- 2011
50. Simple Code Switching Scheme for Security Enhancement of OCDMA Communication System
- Author
-
Feifei Yin, Shizhong Xie, Hongwei Chen, and Zhijian Si
- Subjects
Code division multiple access ,Computer science ,Concatenated error correction code ,Gold code ,Data_CODINGANDINFORMATIONTHEORY ,Communications system ,Chip ,Linear code ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Turbo code ,Electronic engineering ,Electrical and Electronic Engineering ,Encoder - Abstract
A simple code switching scheme for security enhancement of an optical code-division multiple-access (OCDMA) communication system is proposed. The scheme avoids the replacement of all the encoders and decoders in the system and all users' codes are changed by only tuning the center wavelength of the laser source. Each en/decoder contains multiple codes which are nonoverlapping in the spectrum. The scheme is demonstrated in a proof-of-principle transmission experiment. There are three codes on the encoder and decoder pairs, one 2-D code and two 1-D bipolar gold codes with chip number of 63 and 127, respectively. All three codes are decoded successfully after 12.7-km single-mode fiber link.
- Published
- 2011
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