Li, K.; Yang, T.; Wang, X.; Shi, S.; Wang, L.; Chen, X. Frequency-Shift Monitoring of Optical Filter Based on Optical Labels over FTN-WDM Transmission Systems. Photonics2023, 10, 1166.
Li, K.; Yang, T.; Wang, X.; Shi, S.; Wang, L.; Chen, X. Frequency-Shift Monitoring of Optical Filter Based on Optical Labels over FTN-WDM Transmission Systems. Photonics 2023, 10, 1166.
Li, K.; Yang, T.; Wang, X.; Shi, S.; Wang, L.; Chen, X. Frequency-Shift Monitoring of Optical Filter Based on Optical Labels over FTN-WDM Transmission Systems. Photonics2023, 10, 1166.
Li, K.; Yang, T.; Wang, X.; Shi, S.; Wang, L.; Chen, X. Frequency-Shift Monitoring of Optical Filter Based on Optical Labels over FTN-WDM Transmission Systems. Photonics 2023, 10, 1166.
Abstract
Optical network monitoring and soft failure identification such as optical filter shifting and filter tightening is increasingly significant in the future complex and dynamic optical networks. Center frequency shift of optical filtering device in optical network has a serious impact on the perfor-mance of multi-span transmission, especially in high spectrum efficiency faster-than-Nyquist (FTN) transmission systems with various optical switching and add/drop nodes. Existing moni-toring schemes generally have problem of high cost, high complexity and the inability to realize multi-channel online monitoring, which makes it difficult to be applied in wavelength division multiplexing (WDM) system with numerous nodes. In this paper, a monitoring scheme of fre-quency shift of optical filtering devices based on optical label (OL) is proposed and demonstrated. The signal spectrum of each channel is intentionally divided into many sub-bands with corre-sponding optical labels loading. The characters of spectrum power changing caused by frequency shift can be reflected on labels power changing of each sub-band, which are used to monitor and estimate the value of frequency shift by DSP algorithm. Simulation results shows that the that the monitoring errors of frequency shift can be kept below 0.5GHz reasonably after 10-span WDM transmission in FTN polarization multiplexing m-ary quadrature amplitude modulation (PM-mQAM) systems. In addition, 250km fiber transmission experiments are also carried out and the similar results are obtained, which further verify the feasibility of our proposed scheme. The characters of low cost, high reliability and efficiency make it a better candidate for practical ap-plication in the future FTN WDM networks.
Keywords
optical labels; pilot tone; frequency shift monitoring; faster-than-Nyquist
Subject
Engineering, Telecommunications
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
