摘要
在自由空间传输的过程中,轨道角动量(OAM)光束会受到大气湍流的影响,其螺旋相位会产生畸变,导致解调后的信号质量下降。为了研究不同湍流条件下大气湍流对正交频分复用(OFDM)-OAM光信号的影响,使用non-Kolmogorov湍流模型,通过改变模型中折射率结构常数Cn^2和大气指数α模拟不同情况下的大气湍流,测试OAM光信号经过湍流模型后的解调高斯光强图样、光束强度以及其携带的OFDM-16QAM信号的误码率。实验结果表明:non-Kolmogorov湍流模型中Cn^2和α的改变会对解调后的高斯光束以及探测到的OFDM信号产生一定的影响,而在发送端进行信道编码可以从一定程度上改善湍流对传输信号的影响。
In free space, an orbital angular momentum(OAM) beam can be affected by atmospheric turbulence, which distorts the beam’s spiral phase and degrades the signal quality after demodulation. To study the effects of different conditions of atmospheric turbulence on orthogonal frequency division multiplexing(OFDM)-OAM optical signals, a non-Kolmogorov turbulence model is used to simulate atmospheric turbulence by varying the refractive-index structure constant Cn^2 and atmospheric index α. The intensity profile of a demodulated Gauss beam as well as the light intensity and bit error rate of an OFDM-16QAM signal carried by an OAM beam are tested experimentally. Variations of Cn^2 and α affect the Gauss beam and the detected OFDM signal while channel coding reduces the effect of turbulence to some extent.
作者
刘旻雯
李迎春
Liu Minwen;Li Yingchun(Shanghai Institute for Advanced Communication and Data Science,Shanghai 200444,China;Key Laboratory of Specialty Optics and Optical Access Networks,Shayighai University,Shanghai 200444,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2019年第7期25-32,共8页
Acta Optica Sinica
基金
国家自然科学基金(61601279,61601277,61420106011,61635006)
上海市科学发展基金(17010500400,16511104100,18511103400,15530500600,16YF1403900)
关键词
光通信
自由空间光通信
轨道角动量
大气湍流
正交频分复用技术
信道编码
optical communications
free-space optical communications
orbital angular momentum
atmospheric turbulence
orthogonal frequency division multiplexing
channel coding
