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ZTE Communications ›› 2012, Vol. 10 ›› Issue (3): 12-15.

• Special Topic • Previous Articles     Next Articles

Computationally Efficient Nonlinearity Compensation for Coherent Fiber-Optic Systems

Likai Zhu and Guifang Li   

  1. CREOL, The College of Optics and Photonics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA
  • Received:2011-12-01 Online:2012-09-25 Published:2012-09-25
  • About author:Likai Zhu (likai.zhu@oclaro.com) received his BSc and MSc degrees in electrical engineering from Tianjin University, China, in 2003 and 2006. He worked with Dr. Guifang Li in the Optical Fiber Communications Group of CREOL, University of Central Florida, and received his PhD degree in optics. Currently, he is working in research and development of optical fiber communication systems at Oclaro Inc. Dr. Zhu is the author or coauthor of 14 journal papers, eight conference proceedings, and four patents.

    Guifang Li (li@creol.ucf.edu) is professor of optics, electrical & computer engineering and physics at the University of Central Florida. In 1991, he received his PhD degree in electrical engineering from the University of Wisconsin, Madison. His research interests include optical communications and networking, RF photonics, and all-optical signal processing. He is the recipient of the NSF CAREER award, the Office of Naval Research Young Investigator award, and the UCF Research Incentive Award 2006. He is a fellow of SPIE and the Optical Society of America and was an associate editor for Optical Networks. He is currently the deputy editor of Optics Express and an associate editor of IEEE Photonics Technology Letters. He was the principal investigator of the NSF Instrumentation and Laboratory Improvement Program entitled "A National Model for Photonics Proficiency in Undergraduate Electrical Engineering" and the NSF Combined Research and Curriculum Development Program in Optical Communications and Networking. Dr. Li was also the director of the National Science Foundation Integrative Graduate Education and Research Traineeship (IGERT) in Optical Communications and Networking. He received the UCF Teaching Incentive Program (TIP) Award in 2004.

Computationally Efficient Nonlinearity Compensation for Coherent Fiber-Optic Systems

Likai Zhu and Guifang Li   

  1. CREOL, The College of Optics and Photonics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA
  • 作者简介:Likai Zhu (likai.zhu@oclaro.com) received his BSc and MSc degrees in electrical engineering from Tianjin University, China, in 2003 and 2006. He worked with Dr. Guifang Li in the Optical Fiber Communications Group of CREOL, University of Central Florida, and received his PhD degree in optics. Currently, he is working in research and development of optical fiber communication systems at Oclaro Inc. Dr. Zhu is the author or coauthor of 14 journal papers, eight conference proceedings, and four patents.

    Guifang Li (li@creol.ucf.edu) is professor of optics, electrical & computer engineering and physics at the University of Central Florida. In 1991, he received his PhD degree in electrical engineering from the University of Wisconsin, Madison. His research interests include optical communications and networking, RF photonics, and all-optical signal processing. He is the recipient of the NSF CAREER award, the Office of Naval Research Young Investigator award, and the UCF Research Incentive Award 2006. He is a fellow of SPIE and the Optical Society of America and was an associate editor for Optical Networks. He is currently the deputy editor of Optics Express and an associate editor of IEEE Photonics Technology Letters. He was the principal investigator of the NSF Instrumentation and Laboratory Improvement Program entitled "A National Model for Photonics Proficiency in Undergraduate Electrical Engineering" and the NSF Combined Research and Curriculum Development Program in Optical Communications and Networking. Dr. Li was also the director of the National Science Foundation Integrative Graduate Education and Research Traineeship (IGERT) in Optical Communications and Networking. He received the UCF Teaching Incentive Program (TIP) Award in 2004.

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Abstract: Split-step digital backward propagation (DBP) can be combined with coherent detection to compensate for fiber nonlinear impairments. A large number of DBP steps is usually needed for a long-haul fiber system, and this creates a heavy computational load. In a trade-off between complexity and performance, interchannel nonlinearity can be disregarded in order to simplify the DBP algorithm. The number of steps can also be reduced at the expense of performance. In periodic dispersion-managed long-haul transmission systems, optical waveform distortion is dominated by chromatic dispersion. As a result, the nonlinearity of the optical signal repeats in every dispersion period. Because of this periodic behavior, DBP of many fiber spans can be folded into one span. Using this distance-folded DBP method, the required computation for a transoceanic transmission system with full inline dispersion compensation can be reduced by up to two orders of magnitude with negligible penalty. The folded DBP method can be modified to compensate for nonlinearity in fiber links with non-zero residual dispersion per span.

Key words: coherent fiber communication, nonlinearity compensation, folded digital backward propagation

摘要： Split-step digital backward propagation (DBP) can be combined with coherent detection to compensate for fiber nonlinear impairments. A large number of DBP steps is usually needed for a long-haul fiber system, and this creates a heavy computational load. In a trade-off between complexity and performance, interchannel nonlinearity can be disregarded in order to simplify the DBP algorithm. The number of steps can also be reduced at the expense of performance. In periodic dispersion-managed long-haul transmission systems, optical waveform distortion is dominated by chromatic dispersion. As a result, the nonlinearity of the optical signal repeats in every dispersion period. Because of this periodic behavior, DBP of many fiber spans can be folded into one span. Using this distance-folded DBP method, the required computation for a transoceanic transmission system with full inline dispersion compensation can be reduced by up to two orders of magnitude with negligible penalty. The folded DBP method can be modified to compensate for nonlinearity in fiber links with non-zero residual dispersion per span.

关键词: coherent fiber communication, nonlinearity compensation, folded digital backward propagation