共查询到20条相似文献,搜索用时 0 毫秒
1.
D. Calonico E. K. Bertacco C. E. Calosso C. Clivati G. A. Costanzo M. Frittelli A. Godone A. Mura N. Poli D. V. Sutyrin G. Tino M. E. Zucco F. Levi 《Applied physics. B, Lasers and optics》2014,117(3):979-986
To significantly improve the frequency references used in radio-astronomy and the precision measurements in atomic physics, we provide frequency dissemination through a 642-km coherent optical fiber link. On the frequency transfer, we obtained a frequency instability of \(3\times 10^{-19}\) at 1,000 s in terms of Allan deviation on a 5-mHz measurement bandwidth, and an accuracy of \(5\times 10^{-19}\) . The ultimate link performance has been evaluated by doubling the link to 1,284 km, demonstrating a new characterization technique based on the double round trip on a single fiber. This method is an alternative to previously demonstrated techniques for link characterization. In particular, the use of a single fiber may be beneficial to long hauls realizations in view of a continental fiber network for frequency and time metrology, as it avoids the doubling of the amplifiers, with a subsequent reduction in costs and maintenance. A detailed analysis of the results is presented, regarding the phase noise, the cycle-slips detection and removal and the instability evaluation. The observed noise power spectrum is seldom found in the literature; hence, the expression of the Allan deviation is theoretically derived and the results confirm the expectations. 相似文献
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《中国物理 B》2020,(5)
We demonstrate a 300-km +200-km cascaded coherent phase transfer via fiber link. The transfer is divided into a 300-km span and a 200-km span with independent phase locking loops, aiming to extend the phase control bandwidth of the whole link. The phase noise and transfer instability of the cascaded transmission are investigated and compared with those in the case of a single-span 500-km transfer. We achieve the transfer instabilities of 1.8 × 10~(-14) at 1 s, 8.9× 10~(-20) at 10~4 s for the 300-km +200-km cascaded transmission, and 2.7×10~(-14) at 1 s for the 500-km single-span transfer. 相似文献
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随着光钟研究的发展, 光钟的稳定度和不确定度均达到10-18量级. 通过光纤可以实现光钟频率信号的高精度传输, 有望用于未来“秒”定义的复现. 演示了百公里级实验室光纤上的光学频率传递. 对于在实验室70 km光纤盘上实现的光频传递, 光纤相位噪声抑制在1-250 Hz傅里叶频率范围内均接近于光纤延时极限, 对应传输稳定度(Allan偏差)为秒级稳定度1.2×10-15, 10000 s稳定度为1.4×10-18. 实验室100 km光纤的光频传递秒级稳定度也达到了5×10-15. 提出了光纤噪声用户端补偿的方案, 可以简化星形传递网络中心站的复杂度. 在25 km光纤上演示了该传递方案, 实现的传输稳定度接近传统前置补偿传递方案. 相似文献
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Microwave frequency transfer over a 112-km urban fiber link based on electronic phase compensation 下载免费PDF全文
《中国物理 B》2020,(6)
We demonstrate the transmission of a microwave frequency signal at 10 GHz over a 112-km urban fiber link based on a novel simple-architecture electronic phase compensation system. The key element of the system is the low noise frequency divider by 4 to differentiate the frequency of the forward signal from that of the backward one, thus suppressing the effect of Brillouin backscattering and parasitic reflection along the link. In terms of overlapping Allan deviation,the frequency transfer instability of 4.2 × 10~(-15) at 1-s integration time and 1.6 × 10~(-18) at one-day integration time was achieved. In addition, its sensitivity to the polarization mode dispersion in fiber is analyzed by comparing the results with and without laser polarization scrambling. Generally, with simplicity and robustness, the system can offer great potentials in constructing cascaded frequency transfer system and facilitate the building of fiber-based microwave transfer network. 相似文献
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Foreman SM Ludlow AD de Miranda MH Stalnaker JE Diddams SA Ye J 《Physical review letters》2007,99(15):153601
The phase coherence of an ultrastable optical frequency reference is fully maintained over actively stabilized fiber networks of lengths exceeding 30 km. For a 7-km link installed in an urban environment, the transfer instability is 6 x 10{-18} at 1 s. The excess phase noise of 0.15 rad, integrated from 8 mHz to 25 MHz, yields a total timing jitter of 0.085 fs. A 32-km link achieves similar performance. Using frequency combs at each end of the coherent-transfer fiber link, a heterodyne beat between two independent ultrastable lasers, separated by 3.5 km and 163 THz, achieves a 1-Hz linewidth. 相似文献
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针对沙漠环境实地链路存在的温度变化大、室外风力、地表振动等多种复杂噪声来源,通过对系统反馈补偿带宽、反馈补偿强度、光功率等时频传递系统关键参数的优化配置,研究了不同反馈补偿参数下复杂链路噪声的有效抑制技术.全链路的频率传递稳定度8×10~(-14)@1s,1×10~(-16)@1000 s,千秒尺度下时间信号传递的时间方差仅为1.2 ps.实现了氢钟信号在200 km量级沙漠环境实地链路的无损传输.该验证实验在基于短基线干涉测量的卫星测轨系统中发挥了重要作用. 相似文献
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Tatsuya Kimura 《Hyperfine Interactions》1987,37(1-4):311-323
Expected system features, laboratory feasibility studies and current research on associated optical devices and components
directed toward high performance coherent optical fiber transmission systems are discussed. 相似文献
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Future inter-satellite clock comparison on high orbit will require optical time and frequency transmission technology between moving objects. Here, we demonstrate robust optical frequency transmission under the condition of variable link distance. This variable link is accomplished by the relative motion of a single telescope fixed on the experimental platform to a corner-cube reflector(CCR) installed on a sliding guide. Two acousto–optic modulators with different frequencies are used to separat... 相似文献
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为了抑制偏振态漂移带来的功率变化给传输稳定度造成的影响,设计了一种能够快速补偿偏振变化的频率传输系统。该系统将锁模光作为光源,结合PID控制器反馈调节的原理,利用光功率放大器(EDFA)、起偏器、可变光功率衰减器(VOA)和单片机实现。实验结果表明:该系统能够有效抑制偏振态随着环境改变而发生的漂移,经过10 km传输之后的输出光功率稳定度达到110-5,与自由漂相比提高了200倍。将整个系统应用在光梳频率传输系统中,可以提高系统的鉴相精度,在5 GHz的传输频率上,可以有效消除偏振态变化引入的~50 fs的相位抖动。 相似文献
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Research work on coherent optical fiber communications in China is described. Experimental achievements both in basic components and systems have been made since 1981. Several 1.55 μm systems with various modulation schemes such as FSK, DPSK, and MSK have been demonstrated at 140-154 Mbit/s. Two-channel FDM transmissions have been realized. A field test of 622 Mbit/s coherent transmission system and other applications are under planning. 相似文献
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The broadband, coherent nature of narrow-linewidth fiber frequency combs is exploited to measure the full complex spectrum of a molecular gas through multiheterodyne spectroscopy. We measure the absorption and phase shift experienced by each of 155 000 individual frequency-comb lines, spaced by 100 MHz and spanning from 1495 to 1620 nm, after passing through hydrogen cyanide gas. The measured phase spectrum agrees with the Kramers-Kronig transformation of the absorption spectrum. This technique can provide a full complex spectrum rapidly, over wide bandwidths, and with hertz-level accuracy. 相似文献
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O. Terra G. Grosche K. Predehl R. Holzwarth T. Legero U. Sterr B. Lipphardt H. Schnatz 《Applied physics. B, Lasers and optics》2009,97(3):541-551
We have explored the performance of two “dark fibers” of a commercial telecommunication fiber link for a remote comparison
of optical clocks. The two fibers, linking the Leibniz University of Hanover (LUH) with the Physikalisch-Technische Bundesanstalt
(PTB) in Braunschweig, are connected in Hanover to form a total fiber length of 146 km. At PTB the performance of an optical
frequency standard operating at 456 THz was imprinted to a cw transfer laser at 194 THz, and its frequency was transmitted
over the fiber. In order to detect and compensate phase noise related to the optical fiber link we have built a low-noise
optical fiber interferometer and investigated noise sources that affect the overall performance of the optical link. The frequency
stability at the remote end has been measured using the clock laser of PTB’s Yb+ frequency standard operating at 344 THz.
We show that the frequency of a frequency-stabilized fiber laser can be transmitted over a total fiber length of 146 km with
a relative frequency uncertainty below 1×10−19, and short term frequency instability given by the fractional Allan deviation of σ
y
(τ)=3.3×10−15/(τ/s). 相似文献
17.
Joint transfer of time and frequency signals and multi-point synchronization via fiber network 下载免费PDF全文
A system of jointly transferring time signals with a rate of 1 pulse per second(PPS) and frequency signals of 10 MHz via a dense wavelength division multiplex-based(DWDM) fiber is demonstrated in this paper.The noises of the fiber links are suppressed and compensated for by a controlled fiber delay line.A method of calibrating and characterizing time is described.The 1PPS is synchronized by feed-forward calibrating the fiber delays precisely.The system is experimentally examined via a 110 km spooled fiber in laboratory.The frequency stabilities of the user end with compensation are1.8×10~(-14) at 1 s and 2.0×10~(-17) at 10~4 s average time.The calculated uncertainty of time synchronization is 13.1 ps,whereas the direct measurement of the uncertainty is 12 ps.Next,the frequency and 1PPS are transferred via a metropolitan area optical fiber network from one central site to two remote sites with distances of 14 km and 110 km.The frequency stabilities of 14 km link reach 3.0×10~(-14) averaged in 1 s and 1.4×10~(-17) in 10~4 s respectively;and the stabilities of 110 km link are 8.3×10~(-14) and 1.7×10~(-17),respectively.The accuracies of synchronization are estimated to be 12.3 ps for the14 km link and 13.1 ps for the 110 km link,respectively. 相似文献
18.
Olivier Lopez Amale Kanj Paul-Eric Pottie Daniele Rovera Joseph Achkar Christian Chardonnet Anne Amy-Klein Giorgio Santarelli 《Applied physics. B, Lasers and optics》2013,110(1):3-6
In this work, we demonstrate for the first time that it is possible to transfer simultaneously an ultra-stable optical frequency and precise and accurate timing over 540 km using a public telecommunication optical fiber network with Internet data. The optical phase is used to carry both the frequency information and the timestamps by modulating a very narrow optical carrier at 1.55 μm with spread spectrum signals using two-way satellite time transfer modems. The results in terms of absolute time accuracy (250 ps) and long-term timing stability (20 ps) well outperform the conventional Global Navigation Satellite System or geostationary transfer methods. 相似文献
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We evaluated the accuracy of an optical frequency comb in optical fibers by measuring the frequency shift after a sideband from an electro-optic modulator had passed through the fiber. We found that a frequency drift of a few hertz was due largely to a variation in the ambient temperature that corresponded to an increase in the square root of the Allan variance to 0.66 Hz. 相似文献
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We transfer an optical frequency over 251 km of optical fiber with a residual instability of 6x10(-19) at 100 s. This instability and the associated timing jitter are limited fundamentally by the noise on the optical fiber and the link length. We give a simple expression for calculating the achievable instability and jitter over a fiber link. Transfer of optical stability over this long distance requires a highly coherent optical source, provided here by a cw fiber laser locked to a high finesse optical cavity. A sufficient optical carrier signal is delivered to the remote fiber end by incorporating two-way, in-line erbium-doped fiber amplifiers to balance the 62 dB link loss. 相似文献