Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fibe...Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fiber coupling. In this paper, we verified a new adaptive-optic device named adaptive fiber coupler （AFC） which could compensate angular jitters and improve the SMF coupling efficiency in some degree. Experiments of SMF coupling under the angular jitter situation using AFC have been achieved. Stochastic parallel gradient descent （SPGD） algorithm is employed as the control strategy, of which the iteration rate is 625 Hz. In closed loop, the coupling efficiency keeps above 65% when angular errors are below 80/3tad. The compensation bandwidth is 35 Hz at sine-jitter of 15 ~rad amplitude with average coupling efficiency of above 60%. Also, experiments with simulated turbulence have been studied. The average coupling efficiency increases from 31.97% in open loop to 61.33% in closed loop, and mean square error （MSE） of coupling efficiency drops from 7.43% to 1.75%.展开更多
探讨同步传输技术在千兆光网络中的实际应用情况。通过介绍同步传输技术的基本概念,深入讨论超400G光传输网络面临的挑战及其在光传送网(Optical Transport Network,OTN)中的应用前景。研究重点分析调制与解码技术、自适应调整等关键技...探讨同步传输技术在千兆光网络中的实际应用情况。通过介绍同步传输技术的基本概念,深入讨论超400G光传输网络面临的挑战及其在光传送网(Optical Transport Network,OTN)中的应用前景。研究重点分析调制与解码技术、自适应调整等关键技术,并提出改善信号强度、纠正色散问题、克服光纤内非线性影响以及提高光放大器效率的方法。在研究过程中,还优化了前向纠错机制和错误率控制策略,以推动相干传输技术在400G OTN网络中的应用,提高光网络传输效率和扩展容量。展开更多
变电站设备运行环境的干扰较多,导致难以保障检测其运行状态时的正判率。因此,提出基于光纤通信的变电站设备运行状态自动监测方法研究。采用光纤通信技术中的自适应非饱和正交频分复用(Orthogonal Frequency Division Multiplexing,OF...变电站设备运行环境的干扰较多,导致难以保障检测其运行状态时的正判率。因此,提出基于光纤通信的变电站设备运行状态自动监测方法研究。采用光纤通信技术中的自适应非饱和正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术,分析变电站复杂电磁环境下的信道特性,通过动态调整信噪比(Signal Noise Ratio,SNR)阈值,使各子载波的有效性能够支持高质量的设备数据传输。在状态监测阶段,利用Clara算法对原始的电力设备数据进行多次随机抽样和聚类,根据最优电力设备数据聚类中心及其对应的聚类结果,将变电站设备的运行状态划分为正常运行和异常状态。测试结果显示,对于不同监测数据对应运行状态的正判率均在98.0%以上。展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No. 61205069）.
文摘Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fiber coupling. In this paper, we verified a new adaptive-optic device named adaptive fiber coupler （AFC） which could compensate angular jitters and improve the SMF coupling efficiency in some degree. Experiments of SMF coupling under the angular jitter situation using AFC have been achieved. Stochastic parallel gradient descent （SPGD） algorithm is employed as the control strategy, of which the iteration rate is 625 Hz. In closed loop, the coupling efficiency keeps above 65% when angular errors are below 80/3tad. The compensation bandwidth is 35 Hz at sine-jitter of 15 ~rad amplitude with average coupling efficiency of above 60%. Also, experiments with simulated turbulence have been studied. The average coupling efficiency increases from 31.97% in open loop to 61.33% in closed loop, and mean square error （MSE） of coupling efficiency drops from 7.43% to 1.75%.
文摘探讨同步传输技术在千兆光网络中的实际应用情况。通过介绍同步传输技术的基本概念,深入讨论超400G光传输网络面临的挑战及其在光传送网(Optical Transport Network,OTN)中的应用前景。研究重点分析调制与解码技术、自适应调整等关键技术,并提出改善信号强度、纠正色散问题、克服光纤内非线性影响以及提高光放大器效率的方法。在研究过程中,还优化了前向纠错机制和错误率控制策略,以推动相干传输技术在400G OTN网络中的应用,提高光网络传输效率和扩展容量。
