Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems

Compared with high spectrum efficiency faster-than-Nyquist (FTN) backbone network, an enhanced carrier phase recovery based on dual pilot tones is more sensitive to capital cost in FTN metropolitan areas as well as inter-datacenter optical networks. The use of distributed feedback (DFB) lasers is a...

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Main Authors: Jialin You, Tao Yang, Yuchen Zhang, Xue Chen
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/11/11/1048
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author Jialin You
Tao Yang
Yuchen Zhang
Xue Chen
author_facet Jialin You
Tao Yang
Yuchen Zhang
Xue Chen
author_sort Jialin You
collection DOAJ
description Compared with high spectrum efficiency faster-than-Nyquist (FTN) backbone network, an enhanced carrier phase recovery based on dual pilot tones is more sensitive to capital cost in FTN metropolitan areas as well as inter-datacenter optical networks. The use of distributed feedback (DFB) lasers is a way to effectively reduce the cost. However, under high symbol rate FTN systems, equalization-enhanced phase noise (EEPN) induced by a DFB laser with large linewidth will significantly deteriorate the system performance. What is worse, in FTN systems, tight filtering introduces inter-symbol interference so severe that the carrier phase estimation (CPE) algorithm of the FTN systems is more sensitive to EEPN, thus it will lead to a more serious cycle slip problem. In this paper, an enhanced carrier phase recovery based on dual pilot tones is proposed to mitigate EEPN and suppress cycle slip, in which the chromatic dispersion (CD)-aware Tx and LO laser phase noise is estimated, respectively. Offline experiments results under 40 Gbaud polarization multiplexing (PM) 16-quadrature amplitude modulation (QAM) FTN wavelength division multiplexing (FTN-WDM) systems at 0.9 acceleration factor, 5 MHz laser linewidth, and 500 km transmission demonstrate that the proposed algorithm could bring about 0.65 dB improvement of the required SNR for the normalized generalized mutual information of 0.9 compared with the training sequence-based cycle slip suppression carrier phase estimation (TS-CSS) algorithm.
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spelling doaj-art-5e835f39d137483692c6b89a97d95bc82025-08-20T01:53:54ZengMDPI AGPhotonics2304-67322024-11-011111104810.3390/photonics11111048Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission SystemsJialin You0Tao Yang1Yuchen Zhang2Xue Chen3State Key Lab of Information Photonics and Optical Communication, Beijing University of Posts and Telecommunications, Beijing 100876, ChinaState Key Lab of Information Photonics and Optical Communication, Beijing University of Posts and Telecommunications, Beijing 100876, ChinaState Key Lab of Information Photonics and Optical Communication, Beijing University of Posts and Telecommunications, Beijing 100876, ChinaState Key Lab of Information Photonics and Optical Communication, Beijing University of Posts and Telecommunications, Beijing 100876, ChinaCompared with high spectrum efficiency faster-than-Nyquist (FTN) backbone network, an enhanced carrier phase recovery based on dual pilot tones is more sensitive to capital cost in FTN metropolitan areas as well as inter-datacenter optical networks. The use of distributed feedback (DFB) lasers is a way to effectively reduce the cost. However, under high symbol rate FTN systems, equalization-enhanced phase noise (EEPN) induced by a DFB laser with large linewidth will significantly deteriorate the system performance. What is worse, in FTN systems, tight filtering introduces inter-symbol interference so severe that the carrier phase estimation (CPE) algorithm of the FTN systems is more sensitive to EEPN, thus it will lead to a more serious cycle slip problem. In this paper, an enhanced carrier phase recovery based on dual pilot tones is proposed to mitigate EEPN and suppress cycle slip, in which the chromatic dispersion (CD)-aware Tx and LO laser phase noise is estimated, respectively. Offline experiments results under 40 Gbaud polarization multiplexing (PM) 16-quadrature amplitude modulation (QAM) FTN wavelength division multiplexing (FTN-WDM) systems at 0.9 acceleration factor, 5 MHz laser linewidth, and 500 km transmission demonstrate that the proposed algorithm could bring about 0.65 dB improvement of the required SNR for the normalized generalized mutual information of 0.9 compared with the training sequence-based cycle slip suppression carrier phase estimation (TS-CSS) algorithm.https://www.mdpi.com/2304-6732/11/11/1048faster-than-Nyquistequalization-enhanced phase noisecycle slippilot tone
spellingShingle Jialin You
Tao Yang
Yuchen Zhang
Xue Chen
Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems
Photonics
faster-than-Nyquist
equalization-enhanced phase noise
cycle slip
pilot tone
title Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems
title_full Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems
title_fullStr Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems
title_full_unstemmed Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems
title_short Enhanced Carrier Phase Recovery Using Dual Pilot Tones in Faster-than-Nyquist Optical Transmission Systems
title_sort enhanced carrier phase recovery using dual pilot tones in faster than nyquist optical transmission systems
topic faster-than-Nyquist
equalization-enhanced phase noise
cycle slip
pilot tone
url https://www.mdpi.com/2304-6732/11/11/1048
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AT taoyang enhancedcarrierphaserecoveryusingdualpilottonesinfasterthannyquistopticaltransmissionsystems
AT yuchenzhang enhancedcarrierphaserecoveryusingdualpilottonesinfasterthannyquistopticaltransmissionsystems
AT xuechen enhancedcarrierphaserecoveryusingdualpilottonesinfasterthannyquistopticaltransmissionsystems