Performance improvement of a SOA-based coherent optical-OFDM transmission system via nonlinear companding transforms

Azou, Stéphane; Bejan, S.; Morel, Pascal; Sharaiha, Ammar

doi:10.1016/j.optcom.2014.09.067

Cited by 7 publications

(7 citation statements)

References 28 publications

(37 reference statements)

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“…6). First, we can notice the effectiveness of the WNCT scheme once the SOA enters the saturated regime (P out −1.5 dBm); we get an improvement of around 2.5 dB at an EVM of 20%, which confirms the simulation results reported in [6]. Second, we observe a significant decrease in EVM by using a linearization scheme, FLUT being slightly better than LUT; however, at high power, convergence difficulties can degrade the performance.…”

Section: Gain Lut Filter Codebooksupporting

confidence: 85%

“…1; it is a classical layout featuring a PAPR reduction block and a predistorter designed to reduce the nonlinear effects occurring between D/A input and SOA output. We recently investigated the issue of PAPR reduction in [6], with a special focus on nonlinear companding techniques. With such methods, the original signal samples x n have their amplitude modified according to a particular nonlinear function h, the resulting signal y n = h(x n ) is then converted into analog waveform.…”

Section: System Modelmentioning

confidence: 99%

“…However, the authors in [2] report that SOA-based systems may suffer from nonlinear effects such as four wave mixing (FWM) and phase-amplitude coupling, as a result of large PAPR that is typically associated with OFDM signals. In a recent paper [6], we considered various companding schemes for improving a SOA-based CO-OFDM system performances. Thanks to an optimization of Wang's predistortion function [7], we obtained a significant Error Vector Magnitude (EVM) reduction and a better power efficiency.…”

Section: Introductionmentioning

confidence: 99%

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A Joint Linearization/Companding Approach for Improving a CO-OFDM Transmitter

Bejan

Azou

Morel

et al. 2015

IEEE Photon. Technol. Lett.

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International audience—The joint use of peak-to-average power ratio (PAPR) reduction and linearization via digital predistortion is investigated in this letter, with the view to improve the performances of coherent optical OFDM (CO-OFDM) systems employing a semiconductor optical amplifier (SOA). PAPR reduction is performed via Wang's nonlinear companding transform (WNCT), which has been recently pointed out as a pertinent choice for optical communications, and a Filter Lookup Table (FLUT) scheme is considered for linearizing the transmitter. Experimental results prove the effectiveness of the proposed scheme, as a lower EVM is achieved with respect to system implementations using only PAPR reduction or linearization

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Section: Gain Lut Filter Codebooksupporting

confidence: 85%

Section: System Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Joint Linearization/Companding Approach for Improving a CO-OFDM Transmitter

Bejan

Azou

Morel

et al. 2015

IEEE Photon. Technol. Lett.

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“…erefore, mitigating nonlinearity distortion in optical OFDM by reducing PAPR becomes the important issue. In order to reduce PAPR, many methods have been proposed for PAPR reduction, such as companding [7], clipping [8], DCT precoding [9], DFT precoding [10,11], and other methods [12,13]. Recently, a fiber nonlinearity equalizer, which is based on support vector classification for optical OFDM, has been proposed [14].…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigation of Direct Detection Optical OFDM Systems with Clipping and Normalization

Wang

2018

Journal of Electrical and Computer Engineering

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A data clipping and normalization technique is employed to improve the performance of the overall direct detection optical orthogonal frequency division multiplexing (DCO-OFDM) system. A detailed analysis of clipping distortion introduced by digital clipping and normalization is provided. The normalization operation amplifies the clipped data signal to the maximum input amplitude of a digital-to-analog converter (DAC). Based on the analysis, a BER formula of the proposed scheme is derived over the AWGN channel and single fiber channel. Performance of an optical clipped OFDM with normalization is assessed through numerical simulations and Monte Claro simulation over the AWGN channel. Theoretical analysis and simulation results both show that the clipping and normalization scheme can greatly improve the BER of an optical OFDM. In particular, BER performance of the proposed transmission scheme was measured in a practical OFDM transmission platform. The measured experimental results show that the clipped and amplified OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. The received sensitivity at a BER of 10−3 for a 4 Gsamples/s (2.6667 Gbits/s) clipped and normalized OFDM signal with clipping ratio of 4 after 100 km standard single-mode fiber (SMF) transmission was improved by 4.3 dB when compared with the conventional OFDM system. The measured results also showed that the clipped OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. Therefore, a clipping and normalization at the transmitter is most effective, and a substantial performance improvement can be obtained by a simple normalization after clipping.

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“…To satisfy the increasing bandwidth demand in high-speed fiber-optic communication networks, optical orthogonal frequency division multiplexing (O-OFDM) has been widely considered as a promising technology for long-haul high-speed optical transmission systems [1,2], due to its properties of high spectral efficiency, robustness to chromatic dispersion and flexibility on dynamic bandwidth allocation [3]. There are two forms of detecting methods for long-haul optical OFDM systems: direct detection optical OFDM (DDO-OFDM) and coherent optical OFDM (CO-OFDM) [4,5].…”

Section: Introductionmentioning

confidence: 99%

Comparison Study of Long-haul 100-Gb/s DDO-OFDM and CO-OFDM WDM Systems

Liu¹,

Xiao²,

Bi³

et al. 2016

Journal of the Optical Society of Korea

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In this paper, for the first time, the transmission performances of long-haul 100-Gb/s direct detection optical OFDM (DDO-OFDM) and coherent optical OFDM (CO-OFDM) wavelength division multiplexing (WDM) systems are compared by simulation. It provides specific guides for system parameter selection to get a high-performance and cost-effective OFDM WDM system. Specifically, the comparison involves three aspects: launched power is investigated to achieve better system performance; laser linewidth is numerically investigated to choose cost-effective laser; system dispersion tolerances with different laser linewidths are analyzed to further reveal the advantages and disadvantages of these two detecting methods, direct detection and coherent detection, in long-haul OFDM WDM system.

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Performance improvement of a SOA-based coherent optical-OFDM transmission system via nonlinear companding transforms

Cited by 7 publications

References 28 publications

A Joint Linearization/Companding Approach for Improving a CO-OFDM Transmitter

A Joint Linearization/Companding Approach for Improving a CO-OFDM Transmitter

Theoretical and Experimental Investigation of Direct Detection Optical OFDM Systems with Clipping and Normalization

Comparison Study of Long-haul 100-Gb/s DDO-OFDM and CO-OFDM WDM Systems

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