基于波长色散差分的色散温变效应抑制方法

A method for suppression of the thermal fluctuations of the chromatic dispersion based on wavelength dispersion differentiation

为避免瑞利散射带来的信噪比劣化,光纤频率传递中多采用不同的波长进行频率信号的双向传输,因而会受到色散的影响。而在长距离的光纤频率传输系统中,还要考虑色散温变效应。理论分析了由色散温变效应带来的信号相位漂移,提出了一种可抑制色散温变效应的光纤频率传输方法,利用波长的对称关系,使三路光信号之间的色散温变效应差分抵消。研究表明,当激光器的波长间隔相等且为0.8 nm时,采用提出的频率传输方法可将色散温变效应造成的相位漂移抑制到飞秒量级,比经典的频率传输系统小近四个数量级。

Different wavelengths are usually used to transfer the frequency signals bidirectionally in fiber optic frequency transfer system to avoid the signal-to-noise ratio degradation caused by Rayleigh scattering.Not only the chromatic dispersion,the thermal fluctuation of the chromatic dispersion(TFCD)is also a factor that deteriorates the symmetry of the transmission delay of the optical signals,which will affect performance of the system especially in the long-haul transfer case.In this paper,we analyze the phase shift caused by the TFCD,and propose a fiber optic frequency transfer scheme immune to TFCD.By selecting wavelengths with even spacing,the TFCD among three optical signals could be canceled.The study shows the phase shift caused by TFCD can be suppressed to the order of femtosecond by using the proposed scheme when the wavelength spacing is 0.8 nm,which is approximately four orders of magnitude smaller than that of the classic two-wavelength based schemes.