双向时分复用光纤时间传递链路噪声分析

Noise analysis for BTDM-based fiber-optic time transfer link

研究分析了双向时分复用(BTDM)光纤时间传递链路的主要噪声及产生机理,建立了基于BTDM光纤时间传递的链路噪声模型。仿真分析了激光器强度噪声、光放大器增益与个数、接收机带宽等对BTDM光纤时间传递接收信噪比(SNR)的影响。结果表明,BTDM光纤时间传递接收SNR在光放大器达到最优增益时最大,且最大SNR随光放大器个数的增加而增加并趋于稳定;相同长度光纤链路,光放大器个数越多,在一定范围内,激光器相对强度噪声对BTDM光纤时间传递链路接收SNR影响更大,接收机带宽对BTDM光纤时间传递接收信号抖动的影响越小;BTDM光纤时间传递接收SNR随定时信号前光持续时间的增加而减小,并趋于WDM方案的SNR。

Tbe noise model of BTDM fiber-optic time transfer link is established for the analysis of the main noise source and generation mechanism in fiber-optic time transfer system. The effects of RIN of laser,gain of amplifier and the number of amplifiers on the signal-to-noise ratio （SNR） of BTDM fiber- optic time transfer system are studied. The results show that the received SNR of BTDM fiber-optic time transfer is the largest when the optical amplifier reaches the optimal gain,and the maximum SNR increases with the increase of the number of optical amplifiers and tends to be stable. In a certain range, the RIN of laser has more influence the received SNR of BTDM fiber-optic time transfer link, and the bandwidth of receiver has smaller influence on the jitter of the received signal in BTDM fiber-optic time transfer system when it is with the same length of fiber link but more optical amplifiers. The received SNR of BTDM fiber-optic time transfer decreases with the increase of the laser duration before tinting signal and tends to the SNR of WDM-based scheme.