Optical Coherent Detection and Digital Signal Processing of Channel Impairments
Increased spectral efficiency: Information can be encoded in all the available dimensions (polarization + quadrature) of an optical fiber.
Improved optical power efficiency: Any arbitrary modulation format can be supported, allowing techniques like constellation shaping and probabilistic shaping to realize signal-to-noise performance closer to Shannon’s limit.
Digital signal processing compensation of channel impairments: Adaptive linear equalizers can be used to compensate linear impairments like chromatic dispersion and polarization mode dispersion. Fiber nonlinearity can also be mitigated using digital backpropagation, Volterra series, and other approaches. The combination of coherent detection and high-speed DSP enables a highly tunable receiver platform.
Increased receiver sensitivity: It becomes possible to overcome shot-noise limit by increasing the power of the local oscillator, allowing performance that is ultimately limited by the optical signal-to-noise ratio of the link.
Improved spectral management: Digital filters can be used to demultiplex an optical carrier of interest, allowing optical carriers to be spaced closer together, and facilitates “superchannel” transmission.
The first coherent systems to be widely deployed operated at 100-Gb/s using dual-polarization quadriphase shift keying (DP-QPSK). Subsequently, coherent detection has been used in 400-Gb/s superchannel transmission, with various contenders including 4 × 100-Gb/s DP-QPSK, 2 × 200-Gb/s DP-16QAM, and single-carrier 400-Gb/s DP-16QAM. As the cost and power consumption of coherent transponders have decreased over time, they have been pushed ever deeper into the network. Coherent transponders are now used in short-reach systems, and is even under consideration for intra-data center communications.
In this chapter, we review the theory of optical coherent detection, deriving mathematical models of the optical transmitter and receiver as well as an optical fiber link. We also review the most common digital signal processing operations that are performed in a coherent receiver, including linear equalization, optical phase noise compensation, and nonlinear compensation.
- S. Abrar, Compact constellation algorithm for blind equalization of QAM signals, in INCC 2004 (Lahore, 2004), pp. 170–174Google Scholar
- G.P. Agrawal, Nonlinear Fiber Optics, 3rd edn. (Academic, San Diego, 2001)Google Scholar
- E. Auer, An advanced variable data rate modem for Intelsat IDR/IBS services, in 2nd International Workshop Digital Signal Processing Techniques Applied to Space Communications. Paper 1–3 (Turin, 1990)Google Scholar
- J.-X. Cai, H.G. Batshon, M.V. Mazurczyk, O.V. SInkin, D. Wang, M. Paskov, W. Patterson, C.R. Davidson, P. Corbett, G. WOlter, T. Hammon, M. Bolshtyansky, D. Foursa, A. Pilipetskii, 70.4-Tb/s capacity over 7,600 km in C+L-band using coded modulation with hybrid constellation shaping and nonlinearity compensation, in Optical Fiber Conference (OFC), Paper Th5B.2 (Los Angeles, 2017)Google Scholar
- E. Desurvire, Erbium-Doped Fiber Amplifiers, Principles and Applications (Wiley, New York, 2002)Google Scholar
- I.B Djordjevic, H.G. Batshon, L. Xu T. Wang, Coded polarization-multiplexed iterative polar modulation (PM-IPM) for beyond 400 Gb/s serial optical transmission, in Optical Fiber Conference (OFC), Paper OMK2 (San Diego, 2010)Google Scholar
- N.K. Fontaine, S.G. Leon-Saval, R. Ryf, J.R. Salazar Gil, B. ERcan, J. Bland-Hawthorn, Mode-selective dissimilar fiber photonic-lantern spatial multiplexers for few-mode fiber, in European Conference on Optical Communications (ECOC), Paper PD1.C.3 (London, 2013)Google Scholar
- N.K. Fontaine, R. Ryf, H. Chen, A.V. Benitez, B. Guan, R. Scott, B. Ercan, S.J.B. Yoo, L.E. Grüner-Nielsen, Y. Sun, R. Lingle, E. Antonio-Lopez R. Amezcua-Correa, 30×30 MIMO transmission over 15 spatial modes, in Optical Fiber Communication Conference (OFC), Paper Th5C.1 (Los Angeles, 2015)Google Scholar
- S. Haykin, Neural Networks: A Comprehensive Foundation, 2nd edn. (Prentice Hall, Upper Saddle River, 1998)Google Scholar
- S. Haykin, Adaptive Filter Theory, 4th edn. (Prentice Hall, Upper Saddle River, 2002)Google Scholar
- Y.-K. Huang, E. Ip, P.N. Ji, Y. Shao, T. Wang, Y. Aono, Y. Yano, T. Tajima, Terabit/s optical superchannel with flexible modulation format for dynamic distance/route transmission, in Optical Fiber Conference (OFC), Paper OM3.H.4 (Los Angeles, 2012)Google Scholar
- E. Ip, N. Bai, T. Wang, Complexity versus performance tradeoff in fiber nonlinearity compensation using frequency-shaped, multi-subband backpropagation, in Optical Fiber Communication Conference (OFC), Paper OThF4 (Los Angeles, 2011)Google Scholar
- E. Ip, M.-J. Li, K. Bennett, Y.-K. Huang, A. Tanaka, A. Korolev, K. Koreshkov, W. Wood, E. Mateo, J. Hu, Y. Yano, 146λ×6×19-Gbaud wavelength-and mode-division multiplexed transmission over 10×50-km spans of few-mode fiber with a gain-equalized few-mode EDFA. J. Lightwave Technol. 32(4), 790–797 (2014)CrossRefGoogle Scholar
- E. Ip, G. Milione, Y.-K. Huang, T. Wang, Space division multiplexing for optical networks, in Asia Communications and Photonics Conference (ACP), Paper ASu5.D.1 (Hong Kong, 2015)Google Scholar
- O. Ishida, K. Takei, E. Yamazaki, Power efficient DSP implementation for 100G- and beyond multi-haul coherent fiber-optic communications, in Optical Fiber Conference (OFC), Paper W3G.3 (Anaheim, 2016)Google Scholar
- E.I. Jury, Theory and Application of the z-Transform Method (Wiley, New York, 1964)Google Scholar
- R. Kline, Verizon and Nortel complete the first 100G commercial deployment, http://www.ovum.com/news/euronews.asp?id=8315
- M. Kuschnerov, F.N. Hauske, K. Piyawanno, B. Spinnler, A. Napoli, B. Lankl, Adaptive chromatic dispersion equalization for non-dispersion managed coherent systems, in Proceedings of the Optical Fiber Communication Conference (OFC 2009), Paper OMT1 (San Diego, 2009)Google Scholar
- G. Labroille, P. Jian, N. Barré, B. Denolle, J.-F. Morizur, Mode selective 10-mode multiplexer based on multi-plane light conversion, in Optical Fiber Communication Conference (OFC), Paper Th3E.5 (Anaheim, 2016)Google Scholar
- A. Leven, N. Kaneda Y.-K. Chen, A real-time CMA-based 10 Gb/s polarization demultiplexing coherent receiver implemented in an FPGA, in OFC 2008, Paper OTuO2 (San Diego, 2008)Google Scholar
- L. Li, Z. Tao, L. Dou, W. Yan, S. Oda, T. Tanimura, T. Hoshida, J. C. Rasmussen, Implementation efficient nonlinear equalizer based on correlated digital backpropagation, in Optical Fiber Communication Conference (OFC), Paper OWW3 (Los Angeles, 2011)Google Scholar
- X. Liu, Nonlinear effects in phase shift keyed transmission, in Optical Fiber Conference (OFC), Paper ThM4 (Los Angeles, 2004)Google Scholar
- Y. Lu, T. Zhu, L. Chen, X. Bao, Distributed vibration sensor based on coherent detection of phase OTDR. J. Lightwave Technol. 28(22), 3243–3249 (2010)Google Scholar
- A. Mecozzi, C. Antonelli, M. Shtaif, Kramer-Kronig coherent receiver. Optical 3(11), 1220–1227 (2016)Google Scholar
- J.M.D. Mendinueta, B.J. Puttnam, J. Sakaguchi, R.S. Lus, W. Klaus, Y. Awaji, N. Wada, A. Kanno, T. Kawanishi, Investigation of receiver DSP carrier phase estimation rate for self-homodyne space-division multiplexing communication systems, in Optical Fiber Communication Conference (OFC), Paper JTh2A.48 (Anaheim, 2013)Google Scholar
- H. Meyr, M. Moeneclaey, S. Fechtel, Digital Communication Receivers (Wiley, New York, 1997)Google Scholar
- T. Okoshi, K. Kikuchi, Heterodyne type optical fiber communications. IEEE J. Opt. Commun. 2(3), 82–88 (1981)Google Scholar
- A.V. Oppenheim, R.W. Schafer, Discrete-Time Signal Processing (Prentice Hall, Upper Saddle River, 1999)Google Scholar
- T. Ozeki, M. Yoshimura, T. Kudo, H. Lbe, Polarization-mode dispersion equalization experiment using a variable equalizing optical circuit controlled by a pulse-waveform-comparison algorithm, in Optical Fiber Conference (OFC), Paper TuN4 (San Jose, 1994)Google Scholar
- F. Paolucci, F. Cugini, N. Hussain, F. Fresi, L. Poti, OpenFlow-based flexible optical networks with enhanced monitoring functionalities, in European Conference on Optical Communications (ECOC), Paper Tu1.D.5 (Amsterdam, 2012)Google Scholar
- J. Proakis, M. Salehi, Digital Communications, 4th edn. (McGraw-Hill, New York, 2001)Google Scholar
- D. Qian, M.-F. Huang, E. Ip, Y.-K. Huang, Y. Shao, J. Hu, T. Wang, 101.7-Tb/s(370×294-Gb/s) PDM-128QAM-OFDM transmission over 3×55-km SSMF using pilot-based phase noise mitigation, in Optical Fiber Conference (OFC), Paper PDPB5 (Los Angeles, 2011)Google Scholar
- T. Rappaport, Wireless Communications: Principles and Practice (Prentice-Hall, Englewood Cliffs, 1996)Google Scholar
- K. Roberts, 40 Gb/s optical systems with electronic signal processing, in Proceedings of the Lasers and Electro-Optics Society (LEOS), Paper WFF4 (Hualien, 2007)Google Scholar
- R. Ryf, S. Randel, A.H. Gnauck, C. Bolle, R.-J. Essiambre, P. Winzer, D.W. Peckham, A. McCurdy, R. Lingle, Space-division multiplexing over 10 km of three-mode fiber using coherent 6×6 MIMO processing, in Optical Fiber Communication Conference (OFC), Paper PDPB10 (Los Angeles, 2011)Google Scholar
- A. Sano, T. Kobayashi, S. Yamanaka, A. Matsuura, H. Kawakami, Y. Miyamoto, K. Ishihara, H. Masuda, 102.3-Tb/s (224×548-Gb/s) C- and extended L-band all-Raman transmission over 240 km using PDM-64QAM single carrier FDM with digital pilot tone, in Optical Fiber Conference (OFC), Paper PDP5C3 (Los Angeles, 2012)Google Scholar
- M.G. Taylor, Accurate digital phase estimation process for coherent detection using a parallel digital processor, in European Conference on Optical Communications (ECOC), Paper Tu4.2.6 (Glasgow, 2005)Google Scholar
- S. Tsukamoto, D.-S. Ly-Gagnon, K. Katoh, K. Kikuchi, Coherent demodulation of 40-Gbit/s polarization-multiplexed QPSK signals with 16-GHz spacing after 200-km transmission, in Optical Fiber Conference (OFC), Paper PDP29 (Anaheim, 2005)Google Scholar
- R. Weidenfeld, M. Nazarathy, R. Noe, I. Shpantzer, Volterra nonlinear compensation of 100G coherent OFDM with baud-rate ADC, tolerable complexity and low intra-channel FWM/XPM error propagation, in Optical Fiber Communication Conference (OFC), Paper OTuE3 (San Diego, 2010)Google Scholar
- C. Xie, S. Chandrasekhar, Two-stage constant modulus algorithm equalizer for singularity free operation and optical performance monitoring in optical coherent receiver, in Optical Fiber Communication Conference (OFC), Paper OMK3 (San Diego, 2010)Google Scholar
- L. Yan, G. Hu, Demultiplexing in mode-division multiplexing system using multichannel blind deconvolution. IEEE Photon. J. 8(2), 1–11 (2016)Google Scholar
- W. Yan, Z. Tao, L. Dou, L. Li, S. Oda, T. Tanimura, T. Hoshida, J.C. Rasmussen, Low complexity digital perturbation back-propagation, in European Conference on Optical Communications (ECOC), Paper Tu3.A.2 (Geneva, 2011)Google Scholar
- H. Zhang, Z. Tao, L. Liu, S. Oda, T. Hoshida, J. C. Rasmussen, Polarization multiplexing based on independent component analysis in optical coherent receivers, in European Conference on Optical Communications (ECOC), Paper Mo.3.D.5 (Brussels, 2008)Google Scholar