scholarly journals Nonlinearities Diminution in 40 Gb/s 256 QAM Radio over Fiber Link via Machine Learning Method

Author(s):  
Muhammad Usman Hadi

Machine learning (ML) methodologies have been looked upon recently as a potential candidate for mitigating nonlinearity issues in optical communications. In this paper, we experimentally demonstrate a 40-Gb/s 256-quadrature amplitude modulation (QAM) signal-based Radio over Fiber (RoF) system for 50 km of standard single mode fiber length which utilizes support vector machine (SVM) decision method to indicate an effective nonlinearity mitigation. The influence of different impairments in the system is evaluated that includes the influences of Mach-Zehnder Modulator nonlinearities, in-phase and quadrature phase skew of the modulator. By utilizing SVM, the results demonstrated in terms of bit error rate and eye linearity suggest that impairments are significantly reduced and licit input signal power span of 5dBs is enlarged to 15 dBs.

Author(s):  
Muhammad Usman Hadi

We propose a 10-Gb/s 64-quadrature amplitude modulation (QAM) signal-based Radio over Fiber (RoF) system for 50 km of standard single mode fiber length which utilizes Reinforcement Learning (RL) SARSA based decision method to indicate an effective decision which mitigates nonlinearity. By utilizing RL-SARSA algorithm, the results demonstrate that significant reduction can be obtained in terms of bit error rate.


2021 ◽  
Author(s):  
Fabio Barros de Sousa ◽  
Fiterlinge M. de Sousa ◽  
Igor R. S. Miranda ◽  
Waldomiro Paschoal ◽  
Marcos B. C. Costa

Abstract In this work, we presented a radio-over-fiber (ROF) access network through two modulation stages for the generation of multiple millimeter wave (mm-wave) signals with frequencies of 20GHz, 40GHz, 60GHz and 80 GHz for the transmission rate of 10 Gbps as a function of the variation of link distance and signal power. The specific purpose of the paper was to design and to investigate a RoF system based on the variation of mm-wave frequencies in order to implement a simple and effective system. In stage 1, there are two modulators in parallel (MZMa and MZMb) called dual-parallel Mach-Zehnder modulator (DP-MZM) and in stage 2 there is only one modulator (MZMc), connected to three pulse generators: Non-Return-to-Zero (NRZ), Return-to-Zero (RZ). A single-mode fiber (SMF) and Gaussian and an erbium-doped fiber amplifier (EDFA) were also used to send signals to base stations (BSs). The numerical analyzes of the results of the eye diagrams showed excellent bit error rate (BER) and quality factor (Q-factor) values, which proved the good performance of the proposed ROF DP-MZM system, for the three encoding formats used, which was able to generate 3-tupling mm-wave for multiple wireless accesses.


Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 19
Author(s):  
Muhammad Hadi ◽  
Muhammad Awais ◽  
Mohsin Raza ◽  
Kiran Khurshid ◽  
Hyun Jung

This paper demonstrates an unprecedented novel neural network (NN)-based digital predistortion (DPD) solution to overcome the signal impairments and nonlinearities in Analog Optical fronthauls using radio over fiber (RoF) systems. DPD is realized with Volterra-based procedures that utilize indirect learning architecture (ILA) and direct learning architecture (DLA) that becomes quite complex. The proposed method using NNs evades issues associated with ILA and utilizes an NN to first model the RoF link and then trains an NN-based predistorter by backpropagating through the RoF NN model. Furthermore, the experimental evaluation is carried out for Long Term Evolution 20 MHz 256 quadraturre amplitude modulation (QAM) modulation signal using an 850 nm Single Mode VCSEL and Standard Single Mode Fiber to establish a comparison between the NN-based RoF link and Volterra-based Memory Polynomial and Generalized Memory Polynomial using ILA. The efficacy of the DPD is examined by reporting the Adjacent Channel Power Ratio and Error Vector Magnitude. The experimental findings imply that NN-DPD convincingly learns the RoF nonlinearities which may not suit a Volterra-based model, and hence may offer a favorable trade-off in terms of computational overhead and DPD performance.


2020 ◽  
Vol 8 (5) ◽  
pp. 4286-4289

The requirement of the modern application is to transmit wide bandwidth of signal with the low latency. The optical fibers provide wide transmission bandwidth along with very little delay as well as choice on choosing transmission medium for high data rate. However, Stimulated Brillouin Scattering (SBS) is a nonlinear optical effect that restricts power level into a fiber to few milliwatts. It degrades the Q-factor and consequently the bit error rate of an optical fiber link. For suppression of SBS, various approaches have been used previously such as PSK, ASK, FSK, CSRZ-DQPSK etc. Among all the previous techniques, CSRZ-DQPSK transmitter is considered as the most efficient one for suppression of SBS. However, it consists of some drawbacks such as low spectrum efficiency, susceptibility to phase variation and short communication range, due to which requirement arises of upgrading the previous work. Therefore, in the proposed work (i.e. CSRZ-DP-QPSK), DP-QPSK scheme is used which makes the system more efficient as it has high spectrum efficiency and improved sensitivity. Also, the communication range is elongated in present work. The performance evaluation of CSRZ-DP-QPSK approach has been performed in terms of Q-Factor, BER, and threshold. Also, the comparative analysis of the proposed approach with conventional approaches has been performed and from the obtained results it has been demonstrated that proposed work is more efficient than conventional one as it has better SBS tolerance and improved BER.


Author(s):  
Jasper R. Stroud ◽  
Olukayode Okusaga ◽  
Gregory Weaver ◽  
Nelli Mosavi ◽  
Mark A. Foster

Sign in / Sign up

Export Citation Format

Share Document