- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2019
- Distributed optical fiber sensing
- Optical frequency domain reflection
- Polynomial regression algorithm
- Nonlinear tuning compensation
- Optoelectronic Information Science and Engineering
- Hebei University of Technology
-
[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Mitigation of Amplitude and Phase Distortions by Using Conjugate-NOLM Regenerator
摘要： In this paper we propose a conjugate nonlinear optical loop mirror scheme (Conj-NOLM) by cascading two NOLMs with an intermediate optical phase conjugator stage (OPC). This new configuration utilizes mid-span spectral inversion to cancel out the nonlinear phase distortion that is introduced by the two NOLM units. Moreover, numerical investigation has been carried out for 16-QAM signals demonstrating increased robustness against accumulated amplitude and phase distortions in the transmission links.
关键词： conjugate nonlinear optical loop mirror,all-optical regenerator,multilevel amplitude and phase noise suppression
更新于2025-09-23 15:22:29
-
[ASME ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - Boston, Massachusetts, USA (Sunday 2 August 2015)] Volume 8: 27th Conference on Mechanical Vibration and Noise - Nonlinear Free Vibration of Piezoelectric Functionally Graded Beams in Thermal Environment
摘要： Nonlinear free vibration analysis of piezoelectric functionally graded (PFG) beams in thermal environment with any boundary conditions are investigated. The nonlinear governing Equation of motion is derived based on the Euler-Bernoulli beam theory and Von Karman's strain-displacement relation. Simple analytical expression is presented for the nonlinear natural frequency using energy balanced method (EBM). Results are validated and compared with available results in the literature. Effects of different parameters such as vibration amplitude, boundary conditions, material inhomogenity, electrical and thermal loading on the nonlinear behavior of PFG beams are presented.
关键词： Boundary conditions,Energy balanced method,Piezoelectric functionally graded beams,Nonlinear free vibration,Thermal environment
更新于2025-09-23 15:22:29
-
Nonlinear multimodal interference for ytterbium-doped all-fiber mode-locking noise-like pulse generation
摘要： This work demonstrates the generation of the noise-like pulse (NLP) in an all-normal-dispersion passively mode-locked ytterbium-doped ring laser cavity with nonlinear multimodal interference as an equivalent all-fiber saturable absorber, for the first time to the best of our knowledge. Depending on the appropriate optimization of the intra-cavity birefringence and reasonable control of the curving curvature of the multimode fiber, self-started NLP operation can be built and maintained within a wide pump range. Additionally, the effect of the multimode fiber length on the NLP mode-locking performance and the generation of the high power NLP have also been experimentally studied.
关键词： ytterbium-doped fiber,all-fiber laser,nonlinear multimodal interference,noise-like pulse,mode-locking
更新于2025-09-23 15:22:29
-
Mixed Logical Dynamical Nonlinear Model Predictive Controller for Large-Scale Solar Fields
摘要： This paper presents a control algorithm for reducing heat losses caused by clouds in large solar fields. The formulation is based on a Mixed Logical Dynamical (MLD) representation of the solar field plus the application of a Practical Nonlinear Model Predictive Controller (PNMPC) for calculating the optimal control action. The main purpose of the controller is to deactivate fields with inlet temperature greater than outlet temperature and to manipulate the oil flow rate of the activated fields for tracking the reference of the outlet temperature. A simplified lumped parameters model is used for prediction and simulation of the solar fields.
关键词： control of solar fields,mixed logical dynamical systems,Hybrid systems,nonlinear model predictive control
更新于2025-09-23 15:22:29
-
Real-time retrieval of transient heat flux on the surface of participating medium by using the EKF-RLSE technique
摘要： A hybrid algorithm of extended Kalman filtering and recursive least-square estimator (EKF-RLSE) is developed to solve the nonlinear inverse heat conduction-radiation problems in participating medium. By measuring the time-resolved temperature signals from a thermocouple installed on the other boundary of the participating medium, the proposed EKF-RLSE algorithm can realize real-time retrieval of the time-varying heat flux on the medium surface. The influence factors of the sampling interval, measurement and process covariance, forgetting factor, and medium thickness on the reconstruction accuracy and stability of the EKF-RLSE are investigated by numerical experiments. All the estimated results show that the present algorithm is robust and accurate in real-time estimating transient heat flux. If the nonlinear coupled conduction and radiation heat transfer problems is regard as the linear problems, the unknown time-dependent heat flux predicted by the KF-RLSE are also illustrated in this work.
关键词： Participating medium,Kalman filtering,Inverse nonlinear conduction-radiation,Time-varying heat flux,Recursive least squares estimator
更新于2025-09-23 15:22:29
-
All-optical regenerative technique for width-tunable ultra-wideband signal generation
摘要： We demonstrate all-optical generation of width-tunable mono-cycle pulses for ultra-wideband communication. It has been shown that the width of the mono-cycle pulses can be tuned dynamically by simply varying the power of the optical signal. We also investigate the regenerative property of the nonlinear medium-based technique for the generation of mono-cycle pulses. For the purpose of comparison, ultra-wideband mono-cycle pulses are also generated through the optical delay line-based technique. It has been demonstrated through numerical simulations that the nonlinear medium-based technique is highly resilient to amplified spontaneous emission noise that is induced over the optical signal. Furthermore, we have shown that the highly nonlinear fiber-based nonlinear medium performs better than the semiconductor optical amplifier-based medium. Bit error rate measurements are taken for different values of optical signal-to-noise ratios in order to elaborate our work.
关键词： Gaussian mono-cycle pulses,Ultra-wideband over fiber,Semiconductor optical amplifier,Pulse width tuning,Highly nonlinear fiber
更新于2025-09-23 15:22:29
-
Application of combined optical signal processing methods to compensate for nonlinear effects in fibre-optic communication links
摘要： We report on the use of complex quadrature amplitude signal processing methods based on a combination of static neural networks and special modulation techniques. The conditions are found that allow one to construct the most effective combination of signal processing methods for transmitting signals with considerable power (in the nonlinear regime). Using analytical methods, it is shown how the statistical properties of a signal affect the efficiency of combined processing methods.
关键词： neural networks,nonlinear effects,optical fibre,modulation
更新于2025-09-23 15:22:29
-
[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Coherent Detection of Terahertz Waves with a Gas Plasma
摘要： We demonstrate an alternative coherent detection technique via terahertz induced second-harmonic (TISH) in a laser-induced plasma for terahertz waves. In this method, the probe beam requires neither high voltage bias nor optically field bias.
关键词： gas plasma,terahertz detection,Ultrafast nonlinear optics
更新于2025-09-23 15:22:29
-
[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Offsetting Self-Phase Modulation in Optical Fibre by Sinusoidally Time-Varying Phase
摘要： We report on our recent experimental and theoretical results on the use of a sinusoidally time-varying phase to suppress undesirable self-phase modulation of optical pulses propagating in fibre-optic systems.
关键词： phase modulation,nonlinear fibre optics
更新于2025-09-23 15:22:29
-
Analogue Wireless Beamforming Exploiting the Fiber-Nonlinearity of Radio Over Fiber Based C-RANs
摘要： As a key technique of supporting the fixed backbone network, radio over fiber (RoF) systems transmit the radio frequency signals over optical fiber in order to take advantage of their large available bandwidth. In this context, optical fiber aided phased antenna array (PAA) based beamforming techniques have attracted substantial research interest with the goal of improving the cell-edge coverage of cellular base stations. In this paper, we conceive a novel optical fiber aided beamforming technique based on the fiber's nonlinearity to be applied in cloud radio access network (C-RAN). In our proposed technique, the PAA elements are fed by the phase-shifted signals introduced by our highly nonlinear fiber (HNLF) aided phase-shifting solution, which results in an angular beamsteering range of around 90°. This can be exploited by sectorization in cellular networks to reduce the cochannel interference imposed. Furthermore, we exploit the proposed RoF-aided phase shifting technique in C-RAN, where our proposed system takes advantage of the centralized signal processing capability of the RoF system to conceive an all-optical processing based tunable beamforming system. While our flexible HNLF-aided phase-shifting process is confined to the central office of the C-RAN, the end users in the C-RAN cellular networks are capable of flexibly choosing the serving remote radio heads (RRHs) and employing diverse wireless transmission techniques. Through integrating our HNLF-aided phase-shifting design into the proposed C-RAN, we impose as little as 0.1 dB signal-to-noise Ratio (SNR) degradation compared to its traditional electronic counterpart, which requires extra phase-shifters.
关键词： phase-shifter,self-phase modulation,phased array antenna beamforming,C-RAN,cross-phase modulation,highly nonlinear fiber,Optical fiber,optical nonlinearity
更新于2025-09-23 15:22:29