- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 4th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) - Hohhot, China (2019.10.24-2019.10.26)] 2019 4th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) - Laser Molten Pool Temperature Detecting Based on Recursive Estimation in 3D Printing
摘要： Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihhod estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10?5 without a state offset. The SNR gap increases to 4.5 dB with a state offset of ξ = 0.2.
关键词： Atmospheric turbulence,FSO,on-off keying,optical wireless communications
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Regional Symposium on Micro and Nanoelectronics (RSM) - Genting Highland, Pahang, Malaysia (2019.8.21-2019.8.23)] 2019 IEEE Regional Symposium on Micro and Nanoelectronics (RSM) - Simulation and Optimization of Emitter Thickness for Indium Arsenide-Based Thermophotovoltaic Cell
摘要： Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihood estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10?5 without a state offset. The SNR gap increases to 4.5 dB with a state offset of ξ = 0.2.
关键词： Atmospheric turbulence,FSO,on-off keying,optical wireless communications
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE BiCMOS and Compound semiconductor Integrated Circuits and Technology Symposium (BCICTS) - Nashville, TN, USA (2019.11.3-2019.11.6)] 2019 IEEE BiCMOS and Compound semiconductor Integrated Circuits and Technology Symposium (BCICTS) - Integrated CMOS-Compatible Mode-Locked Lasers and Their Optoelectronic Applications
摘要： Free-space optical communication links operating over lognormal turbulence channels using on-off keying (OOK) are studied in this paper. Such systems can suffer from irreducible error floors that result from the use of demodulation with fixed and unoptimized detection thresholds. The resulting error floors are analyzed for the general case of low- and high-state offsets (i.e., finite extinction ratios). An electrical signal-to-noise ratio (SNR) optimized detection system is applied. The system uses the electrical SNRs to implement adaptive detection thresholds and eliminate the error floors. The system can accommodate operation with finite extinction ratios, as it uses the method of moments and maximum likelihhod estimation techniques to estimate the low- and high-state offsets and electrical SNR. Numerical results show that the SNR gap between the electrical-SNR-optimized detection system and the adaptive detection system is 2.3 dB at a bit-error rate of 10?5 without a state offset. The SNR gap increases to 4.5 dB with a state offset of ξ = 0.2.
关键词： Atmospheric turbulence,FSO,on-off keying,optical wireless communications
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Experimental demonstration of atmospheric channel reciprocity in fiber receiving systems
摘要： This paper designs a reciprocity measurement system for atmospheric channel for the first time in China. The mean of reciprocity is higher than 0.8, which proves that the atmospheric channel has strong reciprocity. The research in this paper provides a parameter reference for adaptive optics system design.
关键词： Atmospheric turbulence,Optical Communication,Adaptive optics
更新于2025-09-16 10:30:52
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Performance enhancement of high-capacity coherent DWDM free-space optical communication link using digital signal processing
摘要： In this paper, 1.28 Tbps (32 × 40 Gbps) high-capacity DWDM-FSO link has been investigated for performance enhancement using coherent detection and digital signal processing (DSP). The DP-16QAM-modulated proposed DWDM-FSO link has been analyzed for both adverse weather and turbulent atmospheric conditions. It is observed that when link is subjected to strong turbulence along with adverse weather conditions, the DSP-aided coherent DWDM-FSO receiver achieves target bit error rate (BER) of 10?4 at signal-to-noise ratio (SNR) of 36.4 dB, while for similar conditions, the SNR requirements for IM/DD-based DWDM-FSO link shoots by 12.8 dB to 49.2 dB. Also, in terms of operational link range, the proposed link even under strong turbulent conditions serves 1.88 km, whereas IM/DD link was restricted to mere 1.12 km for target of BER of 10?4, thus producing a decent range increment of 760 m. The proposed link has been designed and investigated using OptiSystem? 14.2.
关键词： Atmospheric turbulence,Coherent detection,Digital signal processing,Free-space optical communication,Gamma–Gamma channel modeling,DWDM
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 19th International Conference on Communication Technology (ICCT) - Xi'an, China (2019.10.16-2019.10.19)] 2019 IEEE 19th International Conference on Communication Technology (ICCT) - Fiber-coupling Efficiency for Satellite-to-ground Laser Links with Angle-of-arrival Fluctuations
摘要： In a satellite-to-ground laser communication system, the presence of atmospheric turbulence and residual angle of arrival fluctuations limit the efficiency with which the propagating beam is coupled into a single-mode fiber. Considering the influence of atmospheric turbulence and residual jitter of angle of arrive, the expression of mean-coupling efficiency is handled in the receiver aperture plane in this paper. The optimal design parameter of the optical receiver system in the satellite-to-ground laser links can be obtained by maximize fiber coupling efficiency. Corresponding numerical results based on the expression derived in this paper will be useful in parametric estimation and optimization of optical receiver system.
关键词： fiber coupling,free space optical communication,angle of arrival,atmospheric turbulence
更新于2025-09-16 10:30:52
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Fast wavefront reconstruction method of reception diversity atmospheric laser communication based on Fractional Brownian motion
摘要： In order to reconstruct the wavefront of reception diversity atmospheric laser communication, the paper first improves the reconstructing modal method of traditional single-input-single-output laser communication based on mutual information. Because the distortion wavefront caused by atmospheric turbulence is a fractal surface of Fractional Brownian motion, a fast wavefront reconstructing method of reception diversity atmospheric laser communication is proposed in this paper. The result shows that the wavefront reconstructing method based on mutual information can optimize the reconstructing performance effectively. Besides, the running time of proposed reconstructing method of reception diversity atmospheric laser communication decreases greatly. Through the comparison of generated wavefront and reconstructed wavefront, the feasibility of the proposed method is demonstrated. It proves that the wavefront reconstructed by proposed method based on Fractional Brownian motion can fit the theory well through the comparison of phase structure function.
关键词： Atmospheric turbulence,Wavefront reconstruction,Fractional Brownian motion,Reception diversity,Mutual information
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Vision Towards Emerging Trends in Communication and Networking (ViTECoN) - Vellore, India (2019.3.30-2019.3.31)] 2019 International Conference on Vision Towards Emerging Trends in Communication and Networking (ViTECoN) - Modeling and Analysis of Hybrid SIM with L-PPM and MSK over Double Generalized Gamma Distribution in Free Space Optical Communication System
摘要： In this paper, we use Double Generalized Gamma (GG) distribution in turbulence induced fading to model the communication channel under weak, moderate and strong turbulence condition. In order to further improve the performance of Free Space Optical (FSO) Communication system over Double GG distribution, we use Hybrid Subcarrier Intensity Modulation (SIM) with L-Pulse Position Modulation (L-PPM) and Minimum Shift Keying (MSK) and analyze its Bit Error Rate (BER) performance for average received irradiance between -12 dBm and 4 dBm. From the simulation results, we observe that BER decreases with decrease in average length of PPM symbol L under different turbulence conditions in FSO Communication system.
关键词： FSO Communication System,Subcarrier Intensity Modulation,Atmospheric Turbulence,Bit Error Rate,Average Irradiance
更新于2025-09-12 10:27:22
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Free Space Optical Communication (System Design, Modeling, Characterization and Dealing with Turbulence) || 2. Real-time measurement of meteorological parameters for estimating low altitude atmospheric turbulence strength (C2 n)
摘要： The major factor that limits the performance of Free Space Optical Communication (FSOC) is atmospheric turbulence which fluctuates over time in accordance with the variations in local meteorological parameters. Estimating the atmospheric turbulence strength (C2n) from measurement data is significant for finding the data rate the system is capable of operating at under different outdoor local environmental conditions. Hence, a low cost customized system for continuously measuring local meteorological data is developed and presented in this chapter. A field test scintillometer setup is established for a link range of 0.5 km at an altitude of 15.25 m. Specialized sensors are interfaced to the digital architectures to acquire the real-time data corresponding to atmospheric changes. The accuracy and performance of the measurement system are tested against standard instruments and the maximum correlation coefficients of 99.92 %, 99.63 %, 99.73 %, and 99.88 % are achieved for wind speed, temperature, relative humidity and pressure respectively. Atmospheric turbulence strength is estimated for the diurnal period using measured meteorological data. The validations of the estimated results with the scintillometer measurement are also analyzed. The weather profile and corresponding C2n variations at our test field for different seasons over a one year period are presented and the results are analyzed.
关键词： atmospheric turbulence,meteorological parameters,scintillometer,PAMELA model,Free Space Optical Communication (FSOC)
更新于2025-09-12 10:27:22
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Free Space Optical Communication (System Design, Modeling, Characterization and Dealing with Turbulence) || 4. Mitigation of beam wandering due to atmospheric turbulence and prediction of control quality using intelligent decision making tools
摘要： In a Free Space Optical Link (FSOL), atmospheric turbulence causes fluctuations in both intensity and phase of the received beam and impairs link performance. Beam motion is one of the main causes for major power loss. This chapter presents an investigation of the performance of two types of controller designed for aiming a laser beam at a particular spot under dynamic disturbances. Multiple experiment observability nonlinear input-output data mapping is used as the principal component for the controllers’ design. The first design is based on the Taguchi method while the second is the Artificial Neural Network (ANN) method. These controllers process the beam location information from a static linear map of a 2D plane: Optoelectronic Position Detector (OPD) as observer, and then generate the necessary outputs to steer the beam with a micro-electromechanical mirror: Fast Steering Mirror (FSM). The beam centroid is computed using a Mono-Pulse Algorithm (MPA). Evidence of suitability and effectiveness of the proposed controllers are comprehensively assessed and quantitatively measured in terms of coefficients of correlation, correction speed, control exactness, centroid displacement and stability of the receiver signal through the experimental results from the FSO link setup established for the horizontal range of 0.5 km at an altitude of 15.25 m. The test field type is open flat terrain, grass and a few isolated obstacles.
关键词： atmospheric turbulence,Artificial Neural Network (ANN),Mono-Pulse Algorithm (MPA),Fast Steering Mirror (FSM),beam wandering,Taguchi method,Free Space Optical Link (FSOL),Optoelectronic Position Detector (OPD)
更新于2025-09-12 10:27:22