Digital coherent technology-based eigenvalue modulated optical fiber transmission system

Maruta, Akihiro; Matsuda, Yuki; Terauchi, Hiroki; Toyota, Akifumi

doi:10.1201/b19377-19

Cited by 9 publications

(5 citation statements)

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“…The CFO at the receiver varied from −5 to 5 GHz. Eigenvalues were detected from the received pulses using the Fourier collocation method [3], [26]. NFT-based CFO estimation was performed based on the procedure described in the previous section.…”

Section: Numerical Simulations a Simulation Modelmentioning

confidence: 99%

Carrier Frequency Offset Estimation in the Eigenvalue Domain

Maeda

Hisano

Yoshida

et al. 2023

J. Lightwave Technol.

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Optical eigenvalue transmission is a promising technique to overcome Kerr nonlinear limits in optical communication systems. The optical eigenvalue associated with the nonlinear Schrödinger equation is invariant during fiber-based nonlinear dispersive transmission. However, the effect of carrier frequency offset (CFO) induces an eigenvalue shift in the presence of the CFO for digitally coherent receivers. The CFO estimation method using eigenvalues capable of achieving highly accurate estimations and can be applied to an eigenvalue transmission system has been proposed. However, a detailed analysis of the eigenvalue-based CFO estimation method is yet to be examined. This study examines the estimation accuracy and limitations of the CFO estimation method through numerical simulations and experiments. The eigenvalue-based method achieves estimation accuracy of less than 10 kHz when the time window size W = 6.4 ns and sampling rate Rs = 20 GSa/s in numerical simulations. Moreover, the estimation error is proportional to energy loss when the time window size W and sampling rate Rs are limited. Through experiments, we achieve a fine estimation accuracy below 1 MHz when W = 12.8 ns and Rs = 5 GSa/s, although the accuracy is limited by the noise effect.

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Section: Numerical Simulations a Simulation Modelmentioning

confidence: 99%

Carrier Frequency Offset Estimation in the Eigenvalue Domain

Maeda

Hisano

Yoshida

et al. 2023

J. Lightwave Technol.

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“…After the windowing and normalization, an eigenvalue pattern is detected from a received pulse using IST. For eigenvalue detection, we used the Fourier collocation method [5], [7], [27], because a root-search algorithm, such as the Newton-Raphson method, is not suitable for finding the "off" state of the eigenvalue in the on-off encoding. In the Fourier collocation method, the received pulse is converted in the spectrum domain by a Fourier transform.…”

Section: Eigenvalue Modulation and Demodulation A Eigenvalue Modulationmentioning

confidence: 99%

“…The transmitted eigenvalue ζ t was stored in the memory as a known value. The eigenvalue pattern was detected by the Fourier collocation method [5], [7], [27] from the received pulse at the receiver. The received eigenvalue ζ r for the CFO estimation was obtained by extracting an eigenvalue that had the maximum imaginary part.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Combining IST-Based CFO Compensation and Neural Network-Based Demodulation for Eigenvalue-Modulated Signal

Mishina

Maeda

Hisano

et al. 2021

J. Lightwave Technol.

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Eigenvalue-based communication technologies using inverse scattering transform (IST) have gained attention as a new transmission strategy in optical fiber communications. In recent years, several studies on artificial neural network (ANN)based equalization and demodulation schemes for eigenvaluemodulated signal have been conducted to enhance the receiver sensitivity. However, in the case of a presence of a carrier frequency offset (CFO) at receiver, the effects of the CFO on ANN receiver of eigenvalue-modulated signal is yet to be reported. In this study, we numerically and experimentally investigated the generalization performances of eigenvalue domain ANN-based demodulator on CFO. Furthermore, we propose to combine an ANN-based demodulator with a CFO compensation method based on IST and a relation between frequency and eigenvalue shifts. The proposed method, based on an appropriate soliton pulse, achieves a high CFO estimation accuracy of submegahertz order even if the CFO reaches ± 2.5 GHz under the noiseless condition. In the presence of noise and a large CFO of 2.5 GHz, the method attains a CFO estimation accuracy below 60 MHz for OSNR=10 dB with a low pilot pulse rate, such as 0.064%. We show the simulation results obtained after applying the proposed CFO compensation to the ANN demodulator, which is valid for 2.5 GHz CFO and long-haul transmission over 5000 km. Experiments performed in this study demonstrate successful demodulation of an eigenvalue-modulated signal with OSNR penalty < 1 dB in the presence of CFO within 1 GHz at 2.5 Gb/s.

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“…[3,4,10]). However, we note that within the aforementioned techniques are mainly focused on compensating the detrimental effects of linear and nonlinear distortions while within the nonlinear Fourier transform (NFT, originally called the inverse scattering transform, IST [11]) based methods nonlinearity serves as an inherent element of the processing method; see the recent reviews [12][13][14][15][16]. In fact, application of this method to optical communications originated from the paper by Hasegawa and Nyu "Eigenvalue communication" [17], where the (relatively simple) modulation of the so-called nonlinear spectrum (or, rather of its solitonic part) was first proposed.…”

Section: Introductionmentioning

confidence: 99%

Periodic nonlinear Fourier transform for fiber-optic communications, Part I: theory and numerical methods

Kamalian

Prilepsky

et al. 2016

Opt. Express

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In this work, we introduce the periodic nonlinear Fourier transform (PNFT) method as an alternative and efficacious tool for compensation of the nonlinear transmission effects in optical fiber links. In the Part I, we introduce the algorithmic platform of the technique, describing in details the direct and inverse PNFT operations, also known as the inverse scattering transform for periodic (in time variable) nonlinear Schrödinger equation (NLSE). We pay a special attention to explaining the potential advantages of the PNFT-based processing over the previously studied nonlinear Fourier transform (NFT) based methods. Further, we elucidate the issue of the numerical PNFT computation: we compare the performance of four known numerical methods applicable for the calculation of nonlinear spectral data (the direct PNFT), in particular, taking the main spectrum (utilized further in Part II for the modulation and transmission) associated with some simple example waveforms as the quality indicator for each method. We show that the Ablowitz-Ladik discretization approach for the direct PNFT provides the best performance in terms of the accuracy and computational time consumption.

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Digital coherent technology-based eigenvalue modulated optical fiber transmission system

Cited by 9 publications

References 0 publications

Carrier Frequency Offset Estimation in the Eigenvalue Domain

Carrier Frequency Offset Estimation in the Eigenvalue Domain

Combining IST-Based CFO Compensation and Neural Network-Based Demodulation for Eigenvalue-Modulated Signal

Periodic nonlinear Fourier transform for fiber-optic communications, Part I: theory and numerical methods

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