Two-fold transmission reach enhancement enabled by transmitter-side digital backpropagation and optical frequency comb-derived information carriers

Galdino

et al. 2018

J. Lightwave Technol.

The efficiency of digital nonlinearity compensation (NLC) is analyzed in the presence of noise arising from amplified spontaneous emission noise (ASE) as well as from a non-ideal transceiver subsystem. Its impact on signal-to-noise ratio (SNR) and reach increase is studied with particular emphasis on split NLC, where the digital back-propagation algorithm is divided between transmitter and receiver. An analytical model is presented to compute the SNR's for non-ideal transmission systems with arbitrary split NLC configurations. When signal-signal nonlinearities are compensated, the performance limitation arises from residual signal-noise interactions. These interactions consist of nonlinear beating between the signal and co-propagating ASE and transceiver noise. While transceiver noise-signal beating is usually dominant for short transmission distances, ASE noisesignal beating is dominant for larger transmission distances. It is shown that both regimes behave differently with respect to the optimal NLC split ratio and their respective reach gains. Additionally, simple formulas for the prediction of the optimal NLC split ratio and the reach increase in those two regimes are reported. It is found that split NLC offers negligible gain with respect to conventional digital back-propagation (DBP) for distances less than 1000 km using standard single-mode fibers and a transceiver (back-to-back) SNR of 26 dB, when transmitter and receiver inject the same amount of noise. However, when transmitter and receiver inject an unequal amount of noise, reach gains of 56% on top of DBP are achievable by properly tailoring the split NLC algorithm. The theoretical findings are confirmed by numerical simulations.

Section: Introductionmentioning

confidence: 99%

The Impact of Transceiver Noise on Digital Nonlinearity Compensation

Semrau

Galdino

et al. 2018

J. Lightwave Technol.

“…Optical techniques include, for example, optical phase conjugation (OPC) using twin waves [1] or OPC devices placed mid-span [2]. Digital techniques include transmitter- [3], [4] and receiver-side [5] digital nonlinearity compensation (NLC), simple nonlinear phase shifts [6], [7], perturbationbased precompensation [8], adaptive filtering [9] and optimum detection [10]. With the exception of optimum detection (a special case of receiver-side NLC for single span transmission) the digital signal processing (DSP) techniques are algorithms which invert the propagation equations for the optical fiber, either exactly or with simplifying approximations.…”

Section: Introductionmentioning

confidence: 99%

“…The demonstrations of multi-channel NLC via receiver-side DBP [5] which takes account of the inter-channel nonlinear distortions, have recently been repeated using similar digital techniques to predistort for nonlinearity at the transmitterdigital precompensation (DPC) [3]. We note that, as might be expected due to the symmetry of the transmission link 1 , the experimentally demonstrated performance of the pre-and postcompensation algorithms is similar; achieving a 100% increase in transmission reach [3], [5]. Whether applying DBP or DPC, additive noise from in-line optical amplifiers is enhanced, which limits the performance of the NLC.…”

Section: Introductionmentioning

confidence: 99%

The Benefit of Split Nonlinearity Compensation for Single-Channel Optical Fiber Communications

IEEE Photon. Technol. Lett.

Ives

Liga

et al. 2016

In this Letter we analyze the benefit of digital compensation of fiber nonlinearity, where the digital signal processing is divided between the transmitter and receiver. The application of the Gaussian noise model indicates that, where there are two or more spans, it is always beneficial to split the nonlinearity compensation. The theory is verified via numerical simulations, investigating transmission of single channel 50 GBd polarization division multiplexed 256-ary quadrature amplitude modulation over 100 km standard single mode fiber spans, using lumped amplification. For this case, the additional increase in mutual information achieved over transmitter-or receiver-side nonlinearity compensation is approximately 1 bit for distances greater than 2000 km. Further, it is shown, theoretically, that the SNR gain for long distances and high bandwidth transmission is 1.5 dB versus transmitter-or receiver-based nonlinearity compensation.

“…Optical techniques include, for example, optical phase conjugation (OPC) using twin waves [1] or OPC devices placed mid-span [2]. Digital techniques include transmitter- [3], [4] and receiver-side [5] digital nonlinearity compensation (NLC), simple nonlinear phase shifts [6], [7], perturbation-based precompensation [8], adaptive filtering [9] and optimum detection [10]. With the exception of optimum detection (a special case of receiver-side NLC for single span transmission) the digital signal processing (DSP) techniques are algorithms which invert the propagation equations for the optical fiber, either exactly or with simplifying approximations.…”

Section: Introductionmentioning

confidence: 99%

“…This algorithm numerically solves the inverse of the optical fiber propagation equations to compensate the linear and nonlinear impairments introduced by the optical fiber transmission; albeit not taking account of amplifier noise. 1 The demonstrations of multi-channel NLC via receiver-side DBP [5] which takes account of the interchannel nonlinear distortions, have recently been repeated using similar digital techniques to predistort for nonlinearity at the transmitter -digital precompensation (DPC) [3]. We note that, as might be expected due to the symmetry of the transmission link, 2 the experimentally demonstrated performance of the pre-and post-compensation algorithms is similar; achieving a 100% increase in transmission reach [3], [5].…”

Section: Introductionmentioning

confidence: 99%

The benefit of split nonlinearity compensation for single channel optical fiber communications

2016 IEEE Photonics Conference (IPC)

Ives

Liga

et al. 2016

Abstract-In this letter, we analyze the benefit of digital compensation of fiber nonlinearity, where the digital signal processing is divided between the transmitter and the receiver. The application of the Gaussian noise model indicates that, where there are two or more spans, it is always beneficial to split the nonlinearity compensation. The theory is verified via numerical simulations, investigating the transmission of a single-channel 50-GBd polarization division multiplexed 4-and 256-ary quadrature amplitude modulation signals over 100-km standard singlemode fiber spans, using lumped amplification. It is shown, theoretically, that the signal-to-noise ratio gain for long distances and high bandwidth transmission is 1.5 dB versus transmitteror receiver-based nonlinearity compensation.