[1] Bondarescu R, Bondarescu M, Hetényi G et al. Geophysical applicability of atomic clocks: direct continental geoid mapping[J]. Geophysical Journal International, 191, 78-82(2012).

[2] Tavella P, Petit G. Precise time scales and navigation systems: mutual benefits of timekeeping and positioning[J]. Satellite Navigation, 1, 1-12(2020).

[3] Zeng T, Yin P L, Yang X P et al. Time and phase synchronization for distributed aperture coherent radar[J]. Journal of Radars, 2, 105-110(2013).

[4] Xu J P, Wang F W, Xu M et al. Chronometric frequency technology and its military application prospect[J]. National Defense Science & Technology, 31, 8-13(2010).

[5] Wang B, Gao C, Chen W L et al. Precise and continuous time and frequency synchronisation at the 5×10-19 accuracy level[J]. Scientific Reports, 2, 1-5(2012).

[6] Śliwczyński Ł, Krehlik P, Czubla A et al. Dissemination of time and RF frequency via a stabilized fibre optic link over a distance of 420 km[J]. Metrologia, 50, 133-145(2013).

[7] Wu G L, Chen J P. Ultra-long haul high-precision fiber-optic two way time transfer[J]. Science & Technology Review, 34, 99-103(2016).

[8] Liang Y F, Xu J N, Wu M et al. Research progress on optical fiber time-frequency synchronization technology[J]. Laser & Optoelectronics Progress, 57, 050004(2020).

[9] Wei H, Lu L, Pu T et al. One-way time transfer method based on dual-fiber link[J]. Chinese Journal of Lasers, 47, 0606005(2020).

[10] Jefferts S R, Weiss M A, Levine J et al. Two-way time and frequency transfer using optical fibers[J]. IEEE Transactions on Instrumentation and Measurement, 46, 209-211(1997).

[11] Zhao B W. Two-way time synchronization using optical fibers[J]. Electronic and Electro-Optical Systems, 5-7, 10(2005).

[12] Chen D, Xu J N, Li Z Z et al. Advancement in time synchronization technology using Bi-contrast methods in optical fiber[J]. Laser & Optoelectronics Progress, 57, 130004(2020).

[13] Smotlacha V, Kuna A, Mache W. Time transfer using fiber links[C](2013).

[14] Krehlik P, Sliwczynski L, Buczek L et al. ELSTAB-fiber-optic time and frequency distribution technology: a general characterization and fundamental limits[J]. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 63, 993-1004(2016).

[15] Zuo F X, Xie K F, Hu L et al. 13134-km fiber-optic time synchronization[J]. Journal of Lightwave Technology, 39, 6373-6380(2021).

[16] Liang J X, Liu C X, Wu R H et al. The bidirectional recirculating loop system for 10000 km fiber-optic time transfer[C](2018).

[17] Amemiya M, Imae M, Fujii Y et al. Precise frequency comparison system using bidirectional optical amplifiers[J]. IEEE Transactions on Instrumentation and Measurement, 59, 631-640(2010).

[18] Sliwczynski Ł, Kolodziej J. Bidirectional optical amplification in long-distance two-way fiber-optic time and frequency transfer systems[J]. IEEE Transactions on Instrumentation and Measurement, 62, 253-262(2013).

[19] Liu Q, Chen W, Xu D et al. Bidirectional erbium-doped fiber amplifiers used in joint frequency and time transfer based on wavelength-division multiplexing technology[J]. Chinese Optics Letters, 13, 110601(2015).

[20] Lu Z, Gui Y Z, Wang J L et al. Fiber-optic time-frequency transfer in gigabit ethernet networks over urban fiber links[J]. Optics Express, 29, 11693-11701(2021).

[21] Śliwczyński Ł, Krehlik P, Buczek Ł et al. Fiber optic RF frequency transfer on the distance of 480 km with the active stabilization of the propagation delay[C], 424-426(2013).

[22] Sliwczynski Ł, Krehlik P, Buczek Ł et al. Frequency transfer in electronically stabilized fiber optic link exploiting bidirectional optical amplifiers[J]. IEEE Transactions on Instrumentation and Measurement, 61, 2573-2580(2012).

[23] Cheng B T, Dai Q, Xie X M et al. Research progress of single-photon detectors[J]. Laser Technology, 46, 601-609(2022).

[24] Pellegrini S, Buller G S, Smith J M et al. Laser-based distance measurement using picosecond resolution time-correlated single-photon counting[J]. Measurement Science and Technology, 11, 712(2000).

[25] Kostamovaara J, Huikari J, Hallman L et al. On laser ranging based on high-speed/energy laser diode pulses and single-photon detection techniques[J]. IEEE Photonics Journal, 7, 7800215(2015).

[26] Li Z P, Ye J T, Huang X et al. Single-photon imaging over 200 km[J]. Optica, 8, 344-349(2021).

[27] Dai H. Experimental research on laser time transfer based on micius satellite[D], 56-68(2020).

[28] Shentu G L, Sun Q C, Jiang X et al. 217 km long distance photon-counting optical time-domain reflectometry based on ultra-low noise up-conversion single photon detector[J]. Optics Express, 21, 24674-24679(2013).

[29] Shao Y, Wang D J, Zhang D et al. Research progress of single photon laser ranging technology[J]. Laser & Optoelectronics Progress, 58, 1011020(2021).

[30] Huang R Y, Zhao W L, Zeng H et al. Development and application of InP-based single photon detectors[J]. Laser & Optoelectronics Progress, 58, 1011009(2021).

[31] Blazej J, Prochazka I, Kodet J et al. Indoor demonstration of free-space picosecond two-way time transfer on single photon level[J]. Proceedings of SPIE, 9224, 92241E(2014).

[32] Trojanek P, Prochazka I. Optical fiber two-way time transfer based on single photon counting approach[J]. The Review of Scientific Instruments, 89, 086106(2018).

[33] Hou F Y, Quan R A, Xiang X et al. Experimental research on two-way quantum time transfer based on solid fiber[J]. Journal of Time and Frequency, 43, 253-261(2020).

[34] Hong H B, Quan R N, Xiang X et al. Demonstration of 50 km fiber-optic two-way quantum clock synchronization[J]. Journal of Lightwave Technology, 40, 3723-3728(2022).

[35] Hachisu H, Fujieda M, Nagano S et al. Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km[J]. Optics Letters, 39, 4072-4075(2014).

[36] Pizzocaro M, Sekido M, Takefuji K et al. Intercontinental comparison of optical atomic clocks through very long baseline interferometry[J]. Nature Physics, 17, 223-227(2021).

[37] Fang J B, Liao C J, Wei Z J et al. Influence of ultra-short laser pulse shapes on gate-mode single photon detection[J]. Acta Photonica Sinica, 38, 2192-2195(2009).

[38] Zeng Z L, Zhu Y, Lu L et al. Research of peak count rate scanning method for single photon detector used in high precision optical transfer time measurement[J]. Chinese Journal of Lasers, 42, 0508003(2015).

[39] Quan R N, Hong H B, Xue W X et al. Implementation of field two-way quantum synchronization of distant clocks across a 7 km deployed fiber link[J]. Optics Express, 30, 10269-10279(2022).

[40] Hou F Y, Quan R N, Dong R F et al. Fiber-optic two-way quantum time transfer with frequency-entangled pulses[J]. Physical Review A, 100, 023849(2019).

[41] Quan R A. Investigation of quantum clock synchronization based on coincident-frequency entanglement and second-order quantum coherence[D], 35-76(2019).

[42] Hu L, Wu G, Zhang H et al. A 300-kilometer optical fiber time transfer using bidirectional TDM dissemination[C], 41-44(2014).

[43] Zuo F X, Chen Z F, Hu L et al. WDM-based fiber-optic time synchronization without requiring link calibration[J]. IEEE Access, 8, 114656-114662(2020).

[44] Wu G L, Hu L, Zhang H et al. High-precision two-way optic-fiber time transfer using an improved time code[J]. Review of Scientific Instruments, 85, 114701(2014).

[45] Cheng N, Chen W, Liu Q et al. Time synchronization technique for joint time and frequency transfer via optical fiber[J]. Chinese Journal of Lasers, 42, 0705002(2015).

[46] Rost M, Piester D, Yang W et al. Time transfer through optical fibres over a distance of 73 km with an uncertainty below 100 ps[J]. Metrologia, 49, 772-778(2012).