高速相干频分复用无源光网络系统辅助管理和控制通道传输与性能

为了在保持帧结构完整性的同时,低代价地传输管理和控制信号,提出面向高速频分复用相干无源光网络（FDM-CPON）的两种传输管理和控制信号传输机制,即数字端辅助管理和控制通道（AMCC）和数据通道的相加和相乘。通过将AMCC传输的通断键控（OOK）信号映射为数据通道信号幅值的变化,完成数据通道信号幅值再调制,成功将AMCC与数据通道相结合,实现了管理和控制信号与数据通道信号的同步传输。实验结果表明,在基于16QAM传输20 km光纤的200 Gbit/s FDM-CPON系统中,当AMCC的带宽和调制因子（MI）相同时,乘性AMCC对于信号性能的影响更小,自身传输信号的质量也更高。在AMCC的MI为26.1%、带宽为24.4 MHz时,乘性AMCC对信号灵敏度的惩罚比加性AMCC小3 dB。以上研究为未来高速相干频分复用无源光网络AMCC传输与系统设计提供重要参考。     

Measurement of the Breakup Cross Sections in ^6He＋^9Be Reaction at 25 MeV／Nucleon

The breakup reaction cross sections were measured for the reaction of^6He at 25 MeV/nucleon from ^9Be target with intensity of 10^5 pps. By fitting the energy spectra of breakup α particles with Gaussian functions, the angular distribution of differential cross sections in the laboratory system has been extracted and compared with the Serber model calculations. The good agreement between the calculation and the experimental data favours a dominant configuration of the ^4He core plus valence neutrons for the structure of^6He.