为了提高四象限探测器(QD)光斑位置检测性能,研究了在高斯光斑模型下影响QD位置检测精度的主要因素。分析了四象限探测器位置检测的基本原理,随后根据误差理论推导出高斯光斑模型下位置检测精度与光斑半径、质心位置和系统信噪比关系的...为了提高四象限探测器(QD)光斑位置检测性能,研究了在高斯光斑模型下影响QD位置检测精度的主要因素。分析了四象限探测器位置检测的基本原理,随后根据误差理论推导出高斯光斑模型下位置检测精度与光斑半径、质心位置和系统信噪比关系的数学模型,通过数值仿真和实验分析验证了该数学模型的有效性,并深入分析了各因素对位置检测精度影响的趋势及大小。研究结果表明,对于四象限探测器高斯光斑位置检测系统,在保证检测范围的条件下,采用较小半径的光斑、选取靠近光敏面中心的工作区域和提高系统信噪比可以提高位置检测精度。当系统信噪比为57.48 d B时,采用束腰半径为0.6 mm的高斯光斑,QD中心点位置检测精度可达0.514μm。展开更多
This paper utilizes uniquely decodable codes[UDCs]in an M-to-1 free-space optical[FSO]system.Benefiting from UDCs’nonorthogonal nature,the sum throughput is improved.We first prove that the uniquely decodable propert...This paper utilizes uniquely decodable codes[UDCs]in an M-to-1 free-space optical[FSO]system.Benefiting from UDCs’nonorthogonal nature,the sum throughput is improved.We first prove that the uniquely decodable property still holds,even in optical fading channels.It is further discovered that the receiver can extract each source’s data from superimposed symbols with only one processing unit.According to theoretical analysis and simulation results,the throughput gain is up to the normalized UDC’s sum rate in high signal-to-noise ratio cases.An equivalent desktop experiment is also implemented to show the feasibility of the UDC-FSO structure.展开更多
An aggregated channel model is achieved by fitting the Weibull distribution, which includes the effects of atmospheric attenuation, M distributed atmospheric turbulence and nonzero boresight pointing errors. With this...An aggregated channel model is achieved by fitting the Weibull distribution, which includes the effects of atmospheric attenuation, M distributed atmospheric turbulence and nonzero boresight pointing errors. With this approximate channel model, the bit error rate(BER) and the ergodic capacity of free-space optical(FSO) communication systems utilizing subcarrier binary phase-shift keying(BPSK) modulation are analyzed, respectively. A closed-form expression of BER is derived by using the generalized Gauss-Lagueree quadrature rule, and the bounds of ergodic capacity are discussed. Monte Carlo simulation is provided to confirm the validity of the BER expressions and the bounds of ergodic capacity.展开更多
文摘为了提高四象限探测器(QD)光斑位置检测性能,研究了在高斯光斑模型下影响QD位置检测精度的主要因素。分析了四象限探测器位置检测的基本原理,随后根据误差理论推导出高斯光斑模型下位置检测精度与光斑半径、质心位置和系统信噪比关系的数学模型,通过数值仿真和实验分析验证了该数学模型的有效性,并深入分析了各因素对位置检测精度影响的趋势及大小。研究结果表明,对于四象限探测器高斯光斑位置检测系统,在保证检测范围的条件下,采用较小半径的光斑、选取靠近光敏面中心的工作区域和提高系统信噪比可以提高位置检测精度。当系统信噪比为57.48 d B时,采用束腰半径为0.6 mm的高斯光斑,QD中心点位置检测精度可达0.514μm。
基金supported in part by the National Natural Science Foundation of China(No.62101527)in part by the Funding Program of Innovation Labs by CIOMP。
文摘This paper utilizes uniquely decodable codes[UDCs]in an M-to-1 free-space optical[FSO]system.Benefiting from UDCs’nonorthogonal nature,the sum throughput is improved.We first prove that the uniquely decodable property still holds,even in optical fading channels.It is further discovered that the receiver can extract each source’s data from superimposed symbols with only one processing unit.According to theoretical analysis and simulation results,the throughput gain is up to the normalized UDC’s sum rate in high signal-to-noise ratio cases.An equivalent desktop experiment is also implemented to show the feasibility of the UDC-FSO structure.
文摘An aggregated channel model is achieved by fitting the Weibull distribution, which includes the effects of atmospheric attenuation, M distributed atmospheric turbulence and nonzero boresight pointing errors. With this approximate channel model, the bit error rate(BER) and the ergodic capacity of free-space optical(FSO) communication systems utilizing subcarrier binary phase-shift keying(BPSK) modulation are analyzed, respectively. A closed-form expression of BER is derived by using the generalized Gauss-Lagueree quadrature rule, and the bounds of ergodic capacity are discussed. Monte Carlo simulation is provided to confirm the validity of the BER expressions and the bounds of ergodic capacity.