| 1. |
- Ahmad, Tauseef, 1986, et al.
(författare)
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Methodology for Power-Aware Coherent Receiver Design
- 2013
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. ; , s. SPT4D.4-
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Konferensbidrag (refereegranskat)abstract
- We describe a methodology to design and evaluate DSP hardware for a coherent receiver. Important parameters that can be assessed include DSP power consumption and chip area.
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| 2. |
- Beygi, Lotfollah, 1977, et al.
(författare)
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A Discrete-Time Model for Uncompensated Single-Channel Fiber-Optical Links
- 2012
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Ingår i: IEEE Transactions on Communications. - 0090-6778 .- 1558-0857. ; 60:11, s. 3440-3450
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Tidskriftsartikel (refereegranskat)abstract
- An analytical discrete-time model is introduced for single-wavelength polarization multiplexed nonlinear fiber-optical channels based on the symmetrized split-step Fourier method (SSFM). According to this model, for high enough symbol rates, a fiber-optic link can be described as a linear dispersive channel with additive white Gaussian noise (AWGN) and a complex scaling. The variance of this AWGN noise and the attenuation are computed analytically as a function of input power and channel parameters. The results illustrate a cubic growth of the noise variance with input power. Moreover, the cross effect between the two polarizations and the interaction of amplifier noise and the transmitted signal due to the nonlinear Kerr effect are described. In particular, it is found that the channel noise variance in one polarization is affected twice as much by the transmitted power in that polarization than by the transmitted power in the orthogonal polarization.The effect of pulse shaping is also investigated through numerical simulations. Finally, it is shown that the analytical performance results based on the new model are in close agreement with numerical results obtained using the SSFM for a symbol rate of 28 Gbaud and above.
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| 3. |
- Beygi, Lotfollah, 1977, et al.
(författare)
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On nonlinearly-induced noise in single-channel optical links with digital backpropagation
- 2013
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 21:22, s. 26376-26386
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the performance limits of electronic chromatic dispersion compensation (EDC) and digital backpropagation (DBP) for a single-channel non-dispersion-managed fiber-optical link. A known analytical method to derive the performance of the system with EDC is extended to derive a first-order approximation for the performance of the system with DBP. In contrast to the cubic growth of the variance of the nonlinear noise-like interference, often called nonlinear noise, with input power for EDC, a quadratic growth is observed with DBP using this approximation. Finally, we provide numerical results to verify the accuracy of the proposed approach and compare it with existing analytical models.
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| 4. |
- Beygi, Lotfollah, 1977, et al.
(författare)
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The Limits of Digital Backpropagation in Nonlinear Coherent Fiber-Optical Links
- 2012
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Ingår i: 2012 38th European Conference and Exhibition on Optical Communications, ECOC 2012; Amsterdam; Netherlands; 16 September 2012 through 20 September 2012. - 9781557529503 ; , s. Art. no. 6706029-
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Konferensbidrag (refereegranskat)abstract
- The performance of a single-channel fiber-optical link is evaluated with linear (dispersive) and nonlinear equalization. The results show a quadratic growth of the noise variance with input power for a system with nonlinear equalization and also justify the known cubic growth for linear equalization.
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| 5. |
- Borkowski, R., et al.
(författare)
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Experimental demonstration of the maximum likelihood-based chromatic dispersion estimator for coherent receivers
- 2014
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Ingår i: Optical Fiber Technology. - : Elsevier BV. - 1095-9912 .- 1068-5200. ; 20:2, s. 158-162
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Tidskriftsartikel (refereegranskat)abstract
- We perform an experimental investigation of a maximum likelihood-based (ML-based) algorithm for bulk chromatic dispersion estimation for digital coherent receivers operating in uncompensated optical networks. We demonstrate the robustness of the method at low optical signal-to-noise ratio (OSNR) and against differential group delay (DGD) in an experiment involving 112 Gbit/s polarization-division multiplexed (PDM) 16-ary quadrature amplitude modulation (16 QAM) and quaternary phase-shift keying (QPSK).
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| 6. |
- Fougstedt, Christoffer, 1990, et al.
(författare)
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Power-Efficient Time-Domain Dispersion Compensation Using Optimized FIR Filter Implementation
- 2015
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Ingår i: Signal Processing in Photonics Communications, SPPCom 2015; Boston, MA; United States; 27 June 2015-1 July 2015. - 9781557520005 ; , s. SpT3D.3-
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Konferensbidrag (refereegranskat)abstract
- We investigate fixed-point aspects and time-domain ASIC implementations of CD compensation. An optimized implementation gives significant power dissipation reduction for short links, with further reduction if pulse shaping is considered.
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| 7. |
- Häger, Christian, 1986, et al.
(författare)
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A Low-Complexity Detector for Memoryless Polarization-Multiplexed Fiber-Optical Channels
- 2014
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Ingår i: IEEE Communications Letters. - 1558-2558 .- 1089-7798. ; 18:2, s. 368-371
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Tidskriftsartikel (refereegranskat)abstract
- A low-complexity detector is introduced for polarization-multiplexed M-ary phase shift keying modulation in a fiber-optical channel impaired by nonlinear phase noise, generalizing a previous result by Lau and Kahn for single-polarization signals. The proposed detector uses phase compensation based on both received signal amplitudes in conjunction with simple straight-line rather than four-dimensional maximum-likelihood decision boundaries.
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| 8. |
- Irukulapati, Naga Vishnukanth, 1987, et al.
(författare)
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Extending Digital Backpropagation to Account for Noise
- 2013
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Ingår i: Proc. of 39th European Conference and Exhibition on Optical Communication (ECOC 2013). - : Institution of Engineering and Technology. - 9781849197595 ; :622 CP, s. We.3.C.4-
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Konferensbidrag (refereegranskat)abstract
- We propose a maximum a posteriori-based scheme that extends digital backpropagation (DBP) by accounting for the nonlinear signal-noise interaction. With periodic dispersion compensation we find up to 20% reach improvement over DBP. For uncompensated links DBP is close to optimal.
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| 9. |
- Irukulapati, Naga Vishnukanth, 1987, et al.
(författare)
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On Maximum Likelihood Sequence Detectors for Single-channel Coherent Optical Communications
- 2014
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Ingår i: 2014 European Conference on Optical Communication, ECOC 2014; Cannes; France; 21 September 2014 through 25 September 2014. - 9782954944401 ; , s. Art. no. 6964134-
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Konferensbidrag (refereegranskat)abstract
- Two different detectors that account for the nonlinear signal–noise interaction in a single channel coherent optical link are compared. The results indicate that accounting for the correlation between the samples leads to improved performance over stochastic digital backpropagation.
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| 10. |
- Irukulapati, Naga Vishnukanth, 1987, et al.
(författare)
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Stochastic Digital Backpropagation
- 2014
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Ingår i: IEEE Transactions on Communications. - 0090-6778 .- 1558-0857. ; 62:11, s. 3956-3968
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a novel detector for single-channel long-haul coherent optical communications, termedstochastic digital backpropagation (SDBP), which takes into account noise from the optical amplifiers in addition to handling deterministic linear and nonlinear impairments. We discuss the design approach behind this detector, which is based on the maximum a posteriori (MAP) principle. As closed-form expressions of the MAP detector are not tractable for coherent optical transmission, we employ the framework of Bayesian graphical models, which allows a numerical evaluation of the proposed detector. Through simulations, we observe that by accounting for nonlinear signal–noise interactions, we achieve a significant improvement in system reach with SDBP over digital backpropagation (DBP) for systems with periodic inlineoptical dispersion compensation. In uncompensated links withhigh symbol rates, the performance difference in terms of system reach for SDBP over DBP is small. In the absence of noise, the proposed detector is equivalent to the well-known DBP detector.
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