摘要
脉冲展宽问题对无线光通信系统的码间串扰影响很大。根据广义惠更斯-菲涅耳原理和修正冯·卡门谱模型,对部分相干高斯-谢尔模型脉冲(GSMP)光束在大气湍流中水平传输时的脉冲展宽问题进行了详细的数值分析。推导出了部分相干GSMP光束在大气湍流中频域和时域的平均光强表达式及脉冲展宽表达式。结果表明:部分相干GSMP光束的扩展受湍流的影响比完全相干GSMP光束受到的影响要小,束腰半径越小的光束受到湍流的影响越大。在频域中,相同的传输条件下,湍流越强且外尺度越大,GSMP光束的展宽效应越明显;在时域中,随着初始脉宽的增加,接收端的相对脉宽迅速减小,在40fs之内,相对脉宽很明显,大于40fs时,接收端的脉冲宽度与初始脉宽无明显差别。
Pulse broadening has a great influence on the increase of inter symbol interference of wireless optical communication system. Based on the generalized Huygens-Fresnel principle and the modified von Karman spectrum model, a detailed numerical analysis on pulse broadening of the partially coherent Gaussian Schell model pulse （GSMP） beam propagation in atmospheric turbulence is discussed. The analytic expressions of the mean intensity and the pulse broadening of the partially coherent GSMP beam propagating in atmospheric turbulence in frequency domain and time domain are derived. The results indicate that the partially coherent GSMP beam is less affected by turbulence than the fully coherent GSMP beam, and that the smaller the partially coherent beam waist radius is, the more serious the beam is affected by turbulence. In the frequency domain, under the same propagation condition, the stronger the turbulence and the bigger the outer scale is, the more obvious the GSMP beams broadening effect is. In the time domain, with the increase of the initial pulse width, the relative pulse width at the receiver ending decreases rapidly. Within 40 femtoseconds, the relative pulse width is very obvious. With more than 40 femtoseconds, there is no significant difference between the pulse width on the receiver and the initial pulse width.
出处
《激光与光电子学进展》
CSCD
北大核心
2016年第8期104-110,共7页
Laser & Optoelectronics Progress
基金
国家自然科学基金(61377080
60977054)
关键词
光通信
大气湍流
高斯-谢尔模型脉冲光束
脉冲展宽
水平传输
optical communications
atmospheric turbulence
Gaussian-Schell model pulse beam
pulse broadening
horizontal-path propagation
