二阶拉曼光纤放大器增益特性研究

为实现较大放大带宽,同时提高输出增益并保持较小的增益平坦度,设计了一种二阶拉曼光纤放大器,采用一个二阶泵浦和四个一阶泵浦对100路信号光进行分布式拉曼放大.首先对二阶拉曼耦合波方程进行数值求解,为进一步提高输出性能,利用粒子群优化算法对二阶拉曼光纤放大器的性能参数进行了优化,然后在相同泵浦参数配置下,对一阶拉曼光纤放大器和二阶拉曼光纤放大器进行对比,最后对二阶拉曼放大器输出增益的影响因素进行分析.通过Matlab仿真,在1 510～1 610 nm的增益带宽范围内所设计的二阶拉曼光纤放大器的平均输出增益为23.768 0 dB,最高输出增益为24.124 4 dB,同时增益平坦度为0.911 2 dB.     

Real-time positioning technology of train based on optical fiber coherent Rayleigh backscattering北大核心CSCD

With the rapid growth of railway mileage in China, the degree of heavy load of railway wagons continues to increase. An interference technology based on Rayleigh backscattering signal in optical fiber was proposed by using existing communication optical cables along railway lines. When the fiber vibrated slightly, the phase and refractive index of the fiber at disturbed position changed, which resulting in the Rayleigh backscattering light. By performing differential calculation on the Rayleigh signal curves before and after the operation, the location of the interference light intensity signal corresponded to the location of the disturbances was obtained. Based on this method, the recognition and positioning of railway vehicles were realized. By collecting and analyzing the time-domain and frequency-domain signal, the signal strength, train length, the number of carriages and other characteristics were extracted, and the model of railway vehicles were accurately recognized. Compared with traditional positioning technologies, this technology could realize long-distance monitoring, and the sensing fiber was buried underground on both sides of the railway, which was conducive to the concealment and protection of optical fiber. Experimental results show that the positioning error of the system is within ±10 m, and the detection of railway speed and position within 25 km can be realized. © 2022 Editorial office of Journal of Applied Optics. All rights reserved.     

Mixed noise removal algorithm of EBAPS image under low illumination condition based on FPGA北大核心CSCD

In order to solve the problem that single median filtering and gaussian filtering algorithm is not effective in suppressing impulse noise and poisson noise simultaneously in low illumination image, and the edge detail protection is insufficient, an open and close mix-median-gaussian (OCMMG) filtering algorithm based on field programmable gate array (FPGA) was proposed. Firstly, the minimum four-direction difference was used to detect the anomaly degree of each pixel point, the weight was allocated according to the threshold of pulse noise discrimination, and the first step was filtering. Then, the four-direction edge detection algorithm was used to extract image edges, and the second step was filtered according to the set edge confidence characterization value. Finally, the images collected by electron bombarded active pixel sensor (EBAPS) under the condition of 1×10−3 lx illumination were processed by FPGA in real time. The experimental results show that the FPGA processing results are consistent with the software simulation processing results. Compared with the median filtering and gaussian filtering algorithm, the peak signal-to-noise ratio (PSNR) of the algorithm is improved by 3.23% and 16.34%, the structural similarity is improved by 14.66% and 33.86%, and the edge retention index is improved by 0.49% and 4.21%, respectively, which can effectively remove the mixed noise of EBAPS image and meet the real-time requirements. © 2022 Editorial office of Journal of Applied Optics. All rights reserved.     

Shooting algorithm and particle swarm optimization based Raman fiber amplifiers gain spectra design

An initial value determination method with a contraction factor for the counter-pumped Raman coupled equations is proposed. This method is used in conjunction with initial guess correction mechanism of Newton's method to construct a new efficient shooting algorithm for the solution of counter-pumped Raman coupled equations. The particle'swarm optimization is used to find the optimal wavelengths and powers for the pumps. By combining the new shooting algorithm and particle swarm optimization a powerful approach to the design of gain spectra for Raman fiber amplifiers is developed. Using this approach a counter-pumped broadband Raman fiber amplifier in C + L-band is designed and optimized. An average on-off gain of 9.3 dB for a bandwidth of 95 nm is obtained using only 4 pumps, with an in-band ripple level of ± 0.7 dB.     

基于混合光纤放大器的波分复用光纤传输系统研究

在研究了入纤功率、光器件的插入损耗以及非归零码中1码出现的概率对系统误码率影响的基础上,提出了一种基于混合光纤放大器的波分复用(WDM)光纤传输系统设计方案,并对该系统的噪声特性进行了详细地研究。提出了一种抑制前向噪声的有效方法,实现了20路WDM信号320km无误码传输。试验结果对基于混合光纤放大器的波分复用光纤传输系统的设计具有一定的指导意义。     

宽带Wilkinson功分器的粒子群优化设计

提出了一种采用圆弧型结构的宽频Wilkinson功分器的优化设计方法。在研究奇模-偶模分析理论的基础上,首先,根据奇-偶模分析理论得出设计电路的参数方程,接着采用粒子群算法对方程进行优化,获得具体的设计参数,有效提高功分器的设计效率与准确性。为了验证设计方案的正确性,设计了8~12 GHz的宽带功分器。测试结果显示,在工作频段范围内,各端口回波损耗小于-20 dB,传输损耗小于3.4 dB,隔离度小于-20 dB,实物测试结果与仿真结果吻合良好,验证了设计方法的可行性。     

基于改进粒子群优化算法的火电厂机组负荷分配

以坑口电厂SIS系统机组负荷优化分配功能模块为应用背景,针对基本粒子群优化算法易陷入局部收敛、收敛速度慢的缺点,提出一种基于惯性权重非线性减小策略的改进粒子群优化算法。并且通过MATLAB与Visual C++混合编程,开发了机组负荷在线优化分配功能模块,提高了算法的计算效率和工程应用价值。     

Flat gain spectrum design of Raman fiber amplifiers based on particle swarm optimization and average power analysis technique

In this work, the modified particle swarm optimization is used as an optimization tool to determine the set of wavelengths and power levels of pumps that delivers a flat gain spectrum for Raman fiber amplifiers. The average power analysis technique is used as a numerical method to solve the coupled Raman amplifier equations. By combining the modified particle swarm optimization and average power analysis technique an efficient algorithm for the design of flat-gain-spectrum broadband Raman fiber amplifiers is constructed. Application of this algorithm to the design of flat-gain-spectrum broadband Raman fiber amplifiers shows that the design efficiency of the new method is improved by 1-2 orders of magnitude compared with similar implementations previously reported in the literature. A 4-backward-pump gain-flattened Raman amplifier with bandwidth of 100-nm and maximum gain ripple of <1.0 dB is designed to demonstrate the technique.     

基于粒子群优化的混沌系统比例-积分-微分控制

基于比例-积分-微分(PID)控制算法的简单性和实用性,但对于复杂非线性系统控制时参数的难以确定问题,运用集群智能中的改进粒子群算法进行PID控制器的优化,并应用于若干混沌系统的控制.对Hénon混沌、Duffing混沌、六辊UC 轧机混沌、Nagumo-sato神经元混沌、Chen氏混沌以及永磁同步电动机混沌的控制进行了仿真研究.研究结果表明： 用PID进行混沌系统的输出反馈控制是有效的,从而拓宽了PID控制的应用范围; 用简单方法控制复杂混沌系统是完全可能的,对混沌系统的控制具有较好的参考价值; 粒子 关键词： 混沌 比例-积分-微分控制 粒子群优化算法     

量子势阱粒子群优化算法的改进研究

为提高量子势阱粒子群优化算法的优化能力, 通过分析目前量子势阱粒子群优化算法的设计过程, 提出了改进的量子势阱粒子群优化算法. 首先, 分别基于Delta势阱、谐振子和方势阱 提出了改进的量子势阱粒子群优化算法, 并提出了基于统计量均值的控制参数设计方法. 然后, 在势阱中心的设计方面, 为强调全局最优粒子的指导作用, 提出了基于自身最优粒子加权平均和动态随机变量的两种设计策略. 实验结果表明, 三种势阱粒子群优化算法性能比较接近, 都优于原算法, 且Delta势阱模型略优于其他两种.     

基于二进制粒子群算法的认知无线电决策引擎

提出了基于粒子群算法的认知无线电决策引擎,并提出了一种种群自适应粒子群算法,利用粒子群算法调整优化无线电参数,运用多载波系统对算法性能进行了仿真分析.实验结果表明基于二进制粒子群算法的认知决策引擎在收敛速度、收敛精度和算法稳定性上都要明显优于经典遗传算法,基于种群自适应粒子群算法的决策引擎则能进一步提高算法初期性能,满足认知无线电实时性要求. 关键词： 认知无线电 粒子群算法 遗传算法 认知决策引擎     

2维静磁场多参量微动粒子群优化算法

提出一种微动粒子群优化算法,针对2维静磁场多参量优化问题,在给出轴上目标轴向磁感应强度分布曲线的前提下,可以得到趋近于该分布曲线的磁结构。该算法分为前后两阶段:第一阶段采用前后试探法(微动),同时也参照最优粒子的信息;第二阶段采用基本粒子群优化算法。微动粒子群优化算法可以发挥多核计算机在工程设计上的潜力,而且即使粒子数目很少,也能不断趋近目标解。     

2维静磁场多参量微动粒子群优化算法

提出一种微动粒子群优化算法,针对2维静磁场多参量优化问题,在给出轴上目标轴向磁感应强度分布曲线的前提下,可以得到趋近于该分布曲线的磁结构。该算法分为前后两阶段:第一阶段采用前后试探法(微动),同时也参照最优粒子的信息;第二阶段采用基本粒子群优化算法。微动粒子群优化算法可以发挥多核计算机在工程设计上的潜力,而且即使粒子数目很少,也能不断趋近目标解。