Modeling of cascaded high isolation bidirectional amplification in long-distance fiber-optic time and frequency synchronization system

• 作者: Kuan-Lin Mu Xing Chen Zheng-Kang Wang Yao-Jun Qiao Song Yu
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS
• 页码范围: 334-343
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-1056/abf105

摘要

We propose a physical model of estimating noise and asymmetry brought by high isolation Bi-directional erbium-doped fiber amplifiers (Bi-EDFAs),no spontaneous lasing even with high gain,in longdistance fiber-optic time and fre-quency (T/F) synchronization system.It is found that the Rayleigh scattering noise can be suppressed due to the high isola-tion design,but the amplified spontaneous emission (ASE) noise generated by the high isolation Bi-EDFA and the bidirec-tional asymmetry of the transmission link caused by the high isolation Bi-EDFA will deteriorate the stability of the system.The calculated results show that under the influence of ASE noise,the frequency instability of a 1200 km system composed of 15 high isolation Bi-EDFAs is 1.773 × 10-13/1 s.And the instability caused by asymmetry is 2.6064 × 10-16/30000-35000 s if the total asymmetric length of the bidirectional link length is 30 m.The intensity noises originating from the laser and detector,the transfer delay fluctuations caused by the variation in ambient temperature and the jitter in laser output wavelength are also studied.The experiment composed of three high isolation Bi-EDFAs is done to confirm the theoreti-cal analysis.In summary,the paper shows that the short-term instability of the T/F synchronization system composed of high isolation Bi-EDFAs is limited by the accumulation of ASE noise of amplifiers and the laser frequency drift,while the long-term instability is limited by the periodic variation in ambient temperature and the asymmetry of the amplifiers.The research results are useful for pointing out the direction to improve the stability of the fiber-optic T/F synchronization system.