Modeling and Optimization of Bidirectional Fiber-Optic Links for Time and Frequency Transfer

Śliwczyński, Ł.; Krehlik, P.; Salwik, Karol

doi:10.1109/tuffc.2018.2889186

Cited by 12 publications

(5 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Last but not least, the proximity of the signals made it difficult (expensive) to separate the signals at amplification points. Therefore, there is no simple way to optimize the gains of amplifiers separately for RF&T and OC subsystems or to use quasi-bidirectional amplifiers with optical isolators preventing propagation of backscattered and reflected signals [28]- [30] However, all these issues could be seriously relaxed if a slightly larger bandwidth could be allocated to the metrological signals (such as 200 GHz), so that the signal spacing could be increased to e.g. ±25 GHz.…”

Section: Discussionmentioning

confidence: 99%

Optical Multiplexing of Metrological Time and Frequency Signals in a Single 100-GHz-Grid Optical Channel

Krehlik

Śliwczyński

Buczek

et al. 2021

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

Self Cite

View full text Add to dashboard Cite

In this paper the concept of co-locating all metrological time and frequency signals in a single optical channel of a standard, 100 GHz-spaced optical grid is presented and evaluated. The solution is intended for situations where only a narrow optical bandwidth is available in a fiber heavily loaded with standard data traffic. We localized the optical reference signals in the middle of the channel, with signals related to RF reference and time tags shifted ±12.5 GHz apart. In the experimental evaluation with a 260 km-long fiber we demonstrate that the stability of frequency signals and the calibration of time tags remained at the very same level of stability and accuracy as for systems utilizing separate channels: the fractional long-term instability for the optical frequency reference was below 5×10 -20 , that for the RF reference at the level of 10 -17 , and the mismatch of the time tag calibration was not more than 10 ps. We also identify possible issues, mainly related to a risk of unwanted Brillouin amplification and scattering.

show abstract

Section: Discussionmentioning

confidence: 99%

Optical Multiplexing of Metrological Time and Frequency Signals in a Single 100-GHz-Grid Optical Channel

Krehlik

Śliwczyński

Buczek

et al. 2021

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Here we set the white noise introduced by the ASE to -78 dBc/Hz with the assistance of the model reported in Ref. [17,36]. As can be seen from Fig.…”

Section: The Impact Of Mars On the System In Different Positionsmentioning

confidence: 99%

Multiple-access relay stations for long-haul fiber-optic radio frequency transfer

Li,

Hu,

Zhang

et al. 2022

Preprint

View full text Add to dashboard Cite

We report on the realization of a long-haul radio frequency (RF) transfer scheme by using multiple-access relay stations (MARSs). The proposed scheme with independent link noise compensation for each fiber sub-link effectively solves the limitation of compensation bandwidth for long-haul transfer. The MARS can have the capability to share the same modulated optical signal for the front and rear fiber sub-links, simplifying the configuration at the repeater station and enabling the transfer system to have the multiple-access capability. At the same time, we for the first time theoretically model the effect of the MARS position on the fractional frequency instability of the fiber-optic RF transfer, demonstrating that the MARS position has little effect on system's performance when the ratio of the front and rear fiber sub-links is around 1 : 1. We experimentally demonstrate a 1 GHz signal transfer by using one MARS connecting 260 and 280 km fiber links with the fractional frequency instabilities of less than 5.9 × 10 −14 at 1 s and 8.5 × 10 −17 at 10,000 s at the remote site and of 5.6 × 10 −14 and 6.6 × 10 −17 at the integration times of 1 s and 10,000 s at the MARS. The proposed scalable technique can arbitrarily add the same MARSs in the fiber link, which has great potential in realizing ultra-long-haul RF transfer.

show abstract

“…Yet another problem with bidirectional amplifiers is that their deployment decreases the power threshold for stimulated Brillouin scattering (SBS), which is the next factor limiting possible gain. Thus finally the total gain of all amplifiers must be substantially lower than the attenuation of the fiber [11], [12]. Operating a long-haul link with low-gain amplifiers also emphasizes the impact of their noises (in case of erbium-doped amplifiers generated mainly by amplified spontaneous emission -ASE), which negatively affects the SNR.…”

Section: Introductionmentioning

confidence: 99%

“…2. We used the dedicated simulation tools developed for bidirectional links with SPBAs based on erbium-doped fiber [12]. The simulations took into account the beating noises resulting from amplifiers' ASE, the odd-order and even-order backscattering, the PN-IN conversion, and the shot and thermal noise of the receiver.…”

Section: Introductionmentioning

confidence: 99%

“…Thus the general conclusion is that for distances exceeding 500 km a reliable operation of links equipped with SPBAs may become problematic. Additionally, it may be noted that for badly conditioned links (long and/or substantially unequal spans, excess attenuations, or reflections), the gain of each amplifier must be carefully optimized before launching the operational connection [11], [12].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrical Regeneration for Long-Haul Fiber-Optic Time and Frequency Distribution Systems

Krehlik

Śliwczyński

Buczek

2021

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

Self Cite

View full text Add to dashboard Cite

In recent years fiber-optic based long-haul installations for time and frequency (T&F) distribution have become operational at various sites. The common practice to cope with large attenuation of long fiber path is to use bidirectional optical amplifiers. This, however, becomes insufficient in case of very long links and/or long spans between amplifiers, because of unavoidable deterioration of the signal-to-noise ratio (SNR). In this paper we present a solution where the optical signal amplification is combined with optical-electrical-optical (OEO) regeneration, performed in a few points along the link. We analyze the impact of replacing some optical amplifiers with OEOs and demonstrate the resulting improvement in terms of SNR of the received optical signal and the phase noise at the output of the T&F distribution system. Laboratory experiments performed with both spooled and metropolitan-area fibers (total length up to 900 km) confirmed the theoretical predictions and showed that placing the OEO regenerators in appropriate points along the link allows reaching the required SNR.

show abstract

Modeling and Optimization of Bidirectional Fiber-Optic Links for Time and Frequency Transfer

Cited by 12 publications

References 37 publications

Optical Multiplexing of Metrological Time and Frequency Signals in a Single 100-GHz-Grid Optical Channel

Optical Multiplexing of Metrological Time and Frequency Signals in a Single 100-GHz-Grid Optical Channel

Multiple-access relay stations for long-haul fiber-optic radio frequency transfer

Electrical Regeneration for Long-Haul Fiber-Optic Time and Frequency Distribution Systems

Contact Info

Product

Resources

About