Author Affiliations
Abstract
1 Key Laboratory of Specialty Fiber Optics and Optical Access Networks, School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China
2 Key Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
3 Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
4 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
We demonstrate a simultaneous transmission of time-frequency and data over a 160-km urban business network in Shanghai. The signals are transmitted through a cascaded optical link consisting of 48 km and 32 km, which are connected by an optical relay. The metrological signals are inserted into the communication network using dense wavelength division multiplexing. The influence of the interference between different signals has been discussed. The experimental results demonstrate that the radio frequency (RF) instability can reach at 1 s and at 10,000 s, and the time interval transfer of one pulse per second (1 PPS) signal with less than 10 ps at 1 s is obtained. This work paves the way for the widespread dissemination of ultra-stable time and frequency signals over the communication networks.
simultaneous transmission radio frequency transfer communication network wavelength multiplexing Chinese Optics Letters
2024, 22(1): 011201
1 中国科学院上海光学精密机械研究所空间激光信息传输与探测技术重点实验室, 上海 201800
2 中国科学院大学材料与光电研究中心, 北京 100049
3 中国科学院上海光学精密机械研究所量子光学重点实验室, 上海 201800
4 中国电子科技集团公司第二十三研究所, 上海 201900
相干探测应用对光纤时频同步技术提出了新的需求,在频率同步的基础上还要能保证相位同步,并且要求低相位噪声传输。为此,研究了一种具有相位噪声净化功能的光纤绝对一致相位同步系统。首先,通过电学锁相环净化频率信号的远端相位噪声,降低了1 GHz频率信号经过26 km长光纤传输后恶化的相位噪声,比如在100 kHz频率偏移处,相位噪声降低了17.0 dB。随后,通过控制时间脉冲的往返延迟和频率信号的往返相移,实现了本远端相位差的绝对一致。当系统经历关闭重启和更改光纤链路操作后,相位差的平均值表现出约2π全周期的1%的不一致性。所设计系统可以在实现频率信号的低相位噪声传输的同时较好地保证了相干性,在相干阵列探测等场景具有重要的应用价值。
光纤光学 光纤链路和子系统 相位同步 相位噪声 不一致性 中国激光
2021, 48(21): 2106001
1 电子信息控制重点实验室, 四川 成都 610036
2 中国科学院上海光学精密机械研究所空间激光信息传输与探测技术重点实验室, 上海 201800
3 中国科学院上海光学精密机械研究所中科院量子光学重点实验室, 上海 201800
随着高精度光钟及其各种应用的发展,人们对时频传输技术的精度要求越来越高。基于光纤的时频传输技术已经较为成熟,而自由空间激光时频传输技术可以应用在不方便铺设光纤、快速机动场合以及星地、星间时频传输领域。介绍了国内外在近地空间以及星地间进行时频传输的研究现状,并对其未来的发展趋势进行了展望。未来自由空间激光时频传输将会朝更高的传输精度、时频传输、测距、通信一体化以及时频空间组网的方向发展。
光通信 时频传输 自由空间 光钟比对 光频梳 激光与光电子学进展
2020, 57(17): 170004
Author Affiliations
Abstract
1 Key Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Univ. Lille, CNRS, UMR 8523—PhLAM—Physique des Lasers Atomes et Molécules, F-59000 Lille, France
4 B I. Stepanov Institute of Physics, NASB, Minsk 220072, Belarus
The point-spread function of an optical system determines its optical resolution for both spatial and temporal imaging. For spatial imaging, it is given by a Fourier transform of the pupil function of the system. For temporal imaging based on nonlinear optical processes, such as sum-frequency generation or four-wave mixing, the point-spread function is related to the waveform of the pump wave by a nonlinear transformation. We compare the point-spread functions of three temporal imaging schemes: sum-frequency generation, co-propagating four-wave mixing, and counter-propagating four-wave mixing, and demonstrate that the last scheme provides the best temporal resolution. Our results are valid for both quantum and classical temporal imaging.
270.5585 Quantum information and processing 110.6915 Time imaging Chinese Optics Letters
2018, 16(9): 092701
1 中国科学院大学, 北京 100049
2 中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室, 上海 201800
3 中国科学院上海光学精密机械研究所中科院量子光学重点实验室, 上海 201800
4 中国科学技术大学, 合肥 安徽 230026
5 中国科学院电磁空间信息重点实验室, 合肥 安徽 230027
为了适应高精度光纤时频传递与光纤通信网融合的发展趋势, 对光纤通信网中常用的波长选择开关(WSS)的时频传递性能进行了研究。基于波分复用、单纤双向还回和光学真时延补偿的方案搭建了一套高精度光纤时频传递系统, 研究了WSS的输出端口、输出损耗和输入光信号的偏振态变化对时频传递性能的影响, 并在此基础上研究了含WSS的时频传递系统的开闭环特性以及闭环情况下WSS的动态切换对时频传递系统的影响。实验结果表明, WSS的引入对光纤时频传递性能的影响是可以控制的, 证实了在含WSS的商用光纤通信网中进行高精度时频传递是可行的。
光纤光学 波长选择开关 光纤时频传递 光纤通信网络
Author Affiliations
Abstract
1 Key Laboratory for Quantum Optics, CAS, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
3 Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
4 e-mail: hwcai@siom.ac.cn
Based on dense wavelength-division multiplexing technology, frequency transfer and time synchronization are simultaneously realized over a compensated cascaded fiber link of 430 km, which is a part of the Beijing–Shanghai optical fiber backbone network. The entire cascaded system consists of two stages with fiber links of 280 and 150 km, respectively. To keep high symmetry and low noise, specific bi-directional erbium-doped fiber amplifiers are used to compensate the large optical attenuation of each fiber link. When the compensation servo is active in every stage, the cascaded system achieves the stability of 1.94×10 13 at 1 s and 1.34×10 16 at 104 s, for frequency transfer. It is also verified that the actual results of the cascaded system are in good agreement with the theoretical ones calculated from error theory. Simultaneously, after calibration of each stage, time synchronization is also realized. The final accuracy of the whole system is within 94 ps.
060.2360 Fiber optics links and subsystems 060.2340 Fiber optics components 120.7000 Transmission Chinese Optics Letters
2016, 14(7): 070602
1 中国科学院上海光学精密机械研究所中科院量子光学重点实验室, 上海 201800
2 中国科学与技术大学量子信息与量子科技前沿协同创新中心, 合肥 安徽 230026
3 中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室, 上海 201800
通过级联方式在京沪光纤骨干网中实现了430 km的高精度频率传递。该级联系统包含了280 km和150 km两级系统,同时为了补偿光纤损耗,在两级链路中采用了低噪声高对称的双向掺铒光纤放大器。当每一级传递系统通过光学补偿方式达到稳定后，整个级联系统引入的频率不稳定度为在1 s处1.02×10-13和在104 s处8.24×10-17，实验结果验证了级联系统的实际结果与两级系统计算结果之间符合误差理论。
光纤光学 频率传递 级联系统 光学补偿
1 中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室, 上海 201800
2 中国科学院上海光学精密机械研究所中国科学院量子光学重点实验室, 上海 201800
3 中国科学技术大学量子信息与量子科技前沿协同创新中心, 安徽 合肥 230026
为实现准国土范围内高精度授时和守时，利用光纤传递铯钟、氢钟等高精度原子钟的时频信号，在实际光纤链路上验证其长距离传递性能。采用波分复用和双向双波长的传输方法，介绍了在275 km京沪干线上实现高精度时频传递的相关工作。针对长距离光纤链路的特点，探讨了链路损耗与散射、色散与频率噪声、补偿系统动态范围和反馈带宽等对时频传递性能的影响。实验获得了频率信号的秒稳定度达5×10-14和天稳定度达7×10-18的传递性能，同时，千秒尺度下的时间方差可达2.4 ps。
光纤光学 时频传递 时间同步 波分复用
1 中国科学院上海光学精密机械研究所中科院量子光学重点实验室, 上海 201800
2 中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室, 上海 201800
The joint transfer of frequency and one pulse-per-second time signals based on dense wavelength division multiplexing technology is demonstrated over a compensated cascaded fiber link of 230 km, consisting of two stages of fiber links with lengths of 150 km and 80 km . A bi-directional erbium-doped fiber amplifier is inserted in the center of 150 km fiber link to compensate for significant optical attenuation. After every stage has achieved the steady state by optical compensation, the Allan deviation of frequency signal of the cascaded system is 3.1×10-14 at 1 s and 6.3 × 10-18 at 104 s respectively; the time deviation of time signal is less than 3.5 ps at an averaging time of 102 s to 104 s. Further, it is verified that the stability of the cascaded link is the standard deviation of the stabilities of the two stages links for both frequency and time signals. After calibration, time synchronization is also realized and the accuracy is within 90 ps.
1 中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室, 上海 201800
2 中国科学院上海光学精密机械研究所中科院量子光学重点实验室, 上海 201800
提出了一种应用于光纤时间频率传递系统中时间信号的校准和同步方案。分析了基于光学补偿方式和波分复用技术的时频传递系统中本地和远地时间信号同步方案的原理，并完成了实验室内50 km 光纤链路的验证实验，时间同步精度为1.6 ps。在110 km 的商用光纤链路上完成了时间信号的同步实验，理论计算的时间同步精度为30.0 ps，对时间信号的误差来源进行了理论分析。
光纤光学 时频传递 时间同步 光学补偿 波分复用
