We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase lockin...We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local site.This passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber links.An optical regeneration station is used in the link for signal amplification and cascaded transmission.The phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is achieved.This work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links.展开更多
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 bandw...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 104 s for the 300-km+200-km cascaded transmission,and 2.7×10^-14 at 1 s for the 500-km single-span transfer.展开更多
Numerically analyzed is the transmission performance of the optical millimeter （mm）-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber. 60 GHz ram-wave subcarrier（SC） signal...Numerically analyzed is the transmission performance of the optical millimeter （mm）-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber. 60 GHz ram-wave subcarrier（SC） signals can be obtained after fiber transmission, simultaneously, the phase-modulated signals can be converted to the intensity-modulated ones. The numerical results show that the optical ram-wave at fading loops has better performance, and the eye diagram still keeps open when optical mm-wave signal is transmitted over 98 km.展开更多
This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR （optical time-domain reflectometry）. Ultra-weak fiber Bragg gratings （UWFBG）, whose backward light intensity is 2-4 order...This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR （optical time-domain reflectometry）. Ultra-weak fiber Bragg gratings （UWFBG）, whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3 m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio （SNR） enables fast detection of distributed vibration without averaging. The fastest vibration of 25 kHz and the slowest vibration of 10Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46nε.展开更多
In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy an...In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy and bypass the optical transmission signal at shortest delay time.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12103059,12033007,12303077,and 12303076)the Fund from the Xi’an Science and Technology Bureau,China(Grant No.E019XK1S04)the Fund from the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.1188000XGJ).
文摘We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local site.This passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber links.An optical regeneration station is used in the link for signal amplification and cascaded transmission.The phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is achieved.This work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFF0200200)the National Natural Science Foundation of China(Grant Nos.91636101,91836301,and 11803041)+1 种基金the West Light Foundation of the Chinese Academy of Sciences(Grant No.XAB2016B47)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21000000)。
文摘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 104 s for the 300-km+200-km cascaded transmission,and 2.7×10^-14 at 1 s for the 500-km single-span transfer.
基金Dr Start-up Fund of Wuyi University,National Natural Science Foundation of China(60677004)
文摘Numerically analyzed is the transmission performance of the optical millimeter （mm）-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber. 60 GHz ram-wave subcarrier（SC） signals can be obtained after fiber transmission, simultaneously, the phase-modulated signals can be converted to the intensity-modulated ones. The numerical results show that the optical ram-wave at fading loops has better performance, and the eye diagram still keeps open when optical mm-wave signal is transmitted over 98 km.
基金This work was supported in part by the National Natural Science Foundation of China （Gram No. 61735031）, Natural Science Foundation of Hubei Province of China （Grant No. 2018CFA056）, and the Excellent Dissertation Cultivation Funds of Wuhan University of Technology （Grant No. 2017-YS-057）.
文摘This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR （optical time-domain reflectometry）. Ultra-weak fiber Bragg gratings （UWFBG）, whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3 m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio （SNR） enables fast detection of distributed vibration without averaging. The fastest vibration of 25 kHz and the slowest vibration of 10Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46nε.
文摘In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy and bypass the optical transmission signal at shortest delay time.
