Opportunities and Challenges of C+L Transmission Systems

C+L open line systems represent a cost-effective way to scale backbone network capacity. In this article, we review challenges and opportunities for C+L line systems stemming from Google's experience in designing, deploying, and operating a global C+L open optical network. We discuss business, operational, and technical aspects of C+L systems, and describe best practices for designing C+L links. Finally, we compare C and C+L systems, showing how the latter not only conceal capacity penalties but can even increase, depending on the deployed fiber types, the total system capacity with respect to two parallel C-band only systems.

[1]  Masaaki Hirano,et al.  Low-Loss and Low-Nonlinearity Pure-Silica-Core Fiber for C- and L-band Broadband Transmission , 2016, Journal of Lightwave Technology.

[2]  Dirk van den Borne,et al.  POLMUX-QPSK modulation and coherent detection: The challenge of long-haul 100G transmission , 2009, 2009 35th European Conference on Optical Communication.

[3]  J. R. Pedrazzani,et al.  A gain-flattened ultra wide band EDFA for high capacity WDM optical communications systems , 1998, 24th European Conference on Optical Communication. ECOC '98 (IEEE Cat. No.98TH8398).

[4]  Vittorio Curri,et al.  Multi-Vendor Experimental Validation of an Open Source QoT Estimator for Optical Networks , 2018, Journal of Lightwave Technology.

[5]  R. Cigliutti,et al.  The LOGON strategy for low-complexity control plane implementation in new-generation flexible networks , 2013, 2013 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC/NFOEC).

[6]  Joseph M. Kahn,et al.  Convex Channel Power Optimization in Nonlinear WDM Systems Using Gaussian Noise Model , 2016, Journal of Lightwave Technology.

[7]  S. D. Emami,et al.  Micro-bending based optical band-pass filter and its application in S-band Thulium-doped fiber amplifier. , 2012, Optics express.

[8]  K. Kikuchi,et al.  Coherent detection of optical quadrature phase-shift keying signals with carrier phase estimation , 2006, Journal of Lightwave Technology.

[9]  R. Theodore Hofmeister,et al.  OPTICAL TECHNOLOGIES FOR DATA CENTER NETWORKS , 2022 .

[10]  C. Glingener,et al.  Bandwidth limitations of broadband distributed Raman fiber amplifiers for WDM systems , 2001, OFC 2001. Optical Fiber Communication Conference and Exhibit. Technical Digest Postconference Edition (IEEE Cat. 01CH37171).

[11]  P. Serena,et al.  Modeling nonlinearity in coherent transmissions with dominant intrachannel-four-wave-mixing. , 2012, Optics express.

[12]  João Pedro,et al.  Maximizing the Capacity of Installed Optical Fiber Infrastructure Via Wideband Transmission , 2018, 2018 20th International Conference on Transparent Optical Networks (ICTON).

[13]  Roland Ryf,et al.  107 Tb/s Transmission of 103-nm Bandwidth over 3×100 km SSMF using Ultra-Wideband Hybrid Raman/SOA Repeaters , 2019, 2019 Optical Fiber Communications Conference and Exhibition (OFC).

[14]  Peter J Winzer,et al.  Fiber-optic transmission and networking: the previous 20 and the next 20 years [Invited]. , 2018, Optics express.

[15]  E. Torrengo,et al.  100Gb/s WDM NRZ-PM-QPSK long-haul transmission experiment over installed fiber probing non-linear reach with and without DCUs , 2009, 2009 35th European Conference on Optical Communication.

[16]  C. Fludger,et al.  Fundamental noise limits in broadband Raman amplifiers , 2001, OFC 2001. Optical Fiber Communication Conference and Exhibit. Technical Digest Postconference Edition (IEEE Cat. 01CH37171).

[17]  P. Poggiolini,et al.  Dispersion Compensation and Mitigation of Nonlinear Effects in 111-Gb/s WDM Coherent PM-QPSK Systems , 2008, IEEE Photonics Technology Letters.

[18]  J.-C. Bouteiller,et al.  Pump-pump four-wave mixing in distributed Raman amplified systems , 2004, Journal of Lightwave Technology.

[19]  John A. Jay.  An Overview of Macrobending and Microbending of Optical Fibers , 2011 .

[20]  R. Theodore Hofmeister,et al.  Scalable and flexible transport networks for inter-datacenter connectivity , 2015, 2015 Optical Fiber Communications Conference and Exhibition (OFC).

[21]  R. Gaudino,et al.  Polarization-Related Statistics of Raman Crosstalk in Single-Mode Optical Fibers , 2016, Journal of Lightwave Technology.

[22]  Nelson Costa,et al.  Towards multiband optical systems , 2018 .

[23]  Anees Shaikh,et al.  Optical Zero Touch Networking — A Large Operator Perspective , 2019, 2019 Optical Fiber Communications Conference and Exhibition (OFC).

[24]  A. Mori,et al.  Tellurite-based EDFAs for broadband communication , 1998 .

[25]  Hong Liu,et al.  Fiber optic communication technologies: What's needed for datacenter network operations , 2010, IEEE Communications Magazine.

[26]  Peter J. Winzer,et al.  From Scaling Disparities to Integrated Parallelism: A Decathlon for a Decade , 2017, Journal of Lightwave Technology.

[27]  Uh-Chan Ryu,et al.  Enhancement of power conversion efficiency for an L-band EDFA with a secondary pumping effect in the unpumped EDF section , 1999, IEEE Photonics Technology Letters.

[28]  Polina Bayvel,et al.  A Closed-Form Approximation of the Gaussian Noise Model in the Presence of Inter-Channel Stimulated Raman Scattering , 2018, Journal of Lightwave Technology.

[29]  Vittorio Curri,et al.  Modelling the Impact of SRS on NLI Generation in Commercial Equipment: An Experimental Investigation , 2018, 2018 Optical Fiber Communications Conference and Exposition (OFC).

[30]  Shu Namiki,et al.  Gain and noise tilt control in multi-wavelength bi-directionally pumped Raman amplifier , 2002, Optical Fiber Communication Conference and Exhibit.

[31]  Ramesh Govindan,et al.  Evolve or Die: High-Availability Design Principles Drawn from Googles Network Infrastructure , 2016, SIGCOMM.

[32]  A. Carena,et al.  Merit of Raman Pumping in Uniform and Uncompensated Links Supporting NyWDM Transmission , 2016, Journal of Lightwave Technology.

[33]  Gabriella Bosco,et al.  Design Strategies and Merit of System Parameters for Uniform Uncompensated Links Supporting Nyquist-WDM Transmission , 2015, Journal of Lightwave Technology.

[34]  P. Winzer.  Energy-Efficient Optical Transport Capacity Scaling Through Spatial Multiplexing , 2011, IEEE Photonics Technology Letters.

[35]  Vittorio Curri,et al.  On the Interplay of Nonlinear Interference Generation With Stimulated Raman Scattering for QoT Estimation , 2018, Journal of Lightwave Technology.

[36]  R. Stolen,et al.  Raman gain in glass optical waveguides , 1973 .

[37]  Tiejun J. Xia,et al.  How will optical transport deal with future network traffic growth? , 2014, 2014 The European Conference on Optical Communication (ECOC).

[38]  Monia Ghobadi,et al.  Optical Layer Failures in a Large Backbone , 2016, Internet Measurement Conference.

[39]  G. Bosco,et al.  Modeling of the Impact of Nonlinear Propagation Effects in Uncompensated Optical Coherent Transmission Links , 2012, Journal of Lightwave Technology.

[40]  J. Bromage.  Raman amplification for fiber communications systems , 2003, Journal of Lightwave Technology.

[41]  Hiroji Masuda,et al.  Hybrid EDFA/Raman Amplifiers , 2004 .

[42]  N. Park,et al.  Low noise, high efficiency L-band EDFA with 980 nm pumping , 1999 .

[43]  Roberto Gaudino,et al.  A Time-Domain Optical Transmission System Simulation Package Accounting for Nonlinear and Polarization-Related Effects in Fiber , 1997, IEEE J. Sel. Areas Commun..

[44]  F. A. Flood.  L-band erbium-doped fiber amplifiers , 2000, Optical Fiber Communication Conference. Technical Digest Postconference Edition. Trends in Optics and Photonics Vol.37 (IEEE Cat. No. 00CH37079).

[45]  Evgeny M. Dianov,et al.  Bismuth-doped optical fibers: a challenging active medium for near-IR lasers and optical amplifiers , 2012, Light: Science & Applications.

[46]  David J. Ives,et al.  Adapting Transmitter Power and Modulation Format to Improve Optical Network Performance Utilizing the Gaussian Noise Model of Nonlinear Impairments , 2014, Journal of Lightwave Technology.

[47]  S. Namiki,et al.  Ultrabroad-band Raman amplifiers pumped and gain-equalized by wavelength-division-multiplexed high-power laser diodes , 2001 .

[48]  Hong Liu,et al.  Jupiter Rising: A Decade of Clos Topologies and Centralized Control in Google's Datacenter Network , 2015, Comput. Commun. Rev..

[49]  R. Theodore Hofmeister,et al.  Lessons learned from open line system deployments , 2017, 2017 Optical Fiber Communications Conference and Exhibition (OFC).

[50]  P. Bayvel,et al.  Investigation of bandwidth loading in optical fibre transmission using amplified spontaneous emission noise. , 2017, Optics express.

[51]  S. Chi,et al.  Four-wave mixing between pump and signal in a distributed Raman amplifier , 2003 .

[52]  Sang Joon Kim,et al.  A Mathematical Theory of Communication , 2006 .