scholarly journals Unrepeatered 240-km 64-QAM Transmission Using Distributed Raman Amplification over SMF Fiber

2020 ◽  
Vol 10 (4) ◽  
pp. 1433
Author(s):  
P. Rosa ◽  
G. Rizzelli ◽  
X. Pang ◽  
O. Ozolins ◽  
A. Udalcovs ◽  
...  
Keyword(s):  
Digital Signal Processor ◽  
Back Propagation ◽  
Digital Signal ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Raman Amplification ◽  
Raman Fiber Laser ◽  
Modulation Format ◽  
Transmission Distance ◽  
Nonlinear Compensation

We present a theoretical and experimental investigation of unrepeatered transmission over standard single-mode fiber (SMF-28) using several schemes of distributed Raman amplification, including first, second, and dual order. In order to further extend the transmission distance, we utilize advanced bidirectional higher-order ultra-long Raman fiber laser-based amplification, where we use fiber Bragg gratings (FBGs) to reflect Stokes-shifted light from the secondary pumps. Our work demonstrates the possibility of transmission up to 240-km span length with a total span loss of 52.7 dB. Here, we use a 28-Gbaud signal using a 64-quadrature amplitude modulation (QAM) modulation format. Our results highlight the contribution of nonlinear compensation using digital back propagation in a digital signal processor (DSP) code at the receiver.

scholarly journals Hybrid compensation of polarization-multiplexed QPSK optical format for high bit rate networks

2020 ◽  
Vol 20 (3) ◽  
pp. 1325
Author(s):  
Omar Y. Shabaan ◽  
Omar A. Athab
Keyword(s):  
Single Channel ◽  
Optical Network ◽  
Digital Signal ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Bit Rate ◽  
Fiber Network ◽  
Transmission Distance ◽  
Regeneration Stage ◽  
High Bit Rate

<span lang="EN-GB">Transmitting the highest capacity throughput over the longest possible distance without any regeneration stage is an important goal of any long-haul optical network system. Accordingly, Polarization-Multiplexed Quadrature Phase-Shift-Keying (PM-QPSK) was introduced lately to achieve high bit-rate with relatively high spectral efficiency. Unfortunately, the required broad bandwidth of PM-QPSK increases the linear and nonlinear impairments in the physical layer of the optical fiber network. Increased attention has been spent to compensate for these impairments in the last years. In this paper, Single Mode Fiber (SMF), single channel, PM-QPSK transceiver was simulated, with a mix of optical and electrical (Digital Signal Processing (DSP)) compensation stages to minimize the impairments. The behaviour of the proposed system was investigated under four conditions: without compensation, with only optical compensator, with only DSP compensator and finally with both compensators. An evidence improvement was noticed in the case of hybrid compensation, where the transmission distance was multiplied from (720 km) to more than (3000 km) at 40 Gb/s.</span>

scholarly journals Tunable Optoelectronic Chromatic Dispersion Compensation Based on Machine Learning for Short-Reach Transmission

2019 ◽  
Vol 9 (20) ◽  
pp. 4332 ◽  
Author(s):  
Stenio M. Ranzini ◽  
Francesco Da Ros ◽  
Henning Bülow ◽  
Darko Zibar
Keyword(s):  
Machine Learning ◽  
Digital Signal Processor ◽  
Forward Error Correction ◽  
Dispersion Compensation ◽  
Chromatic Dispersion ◽  
Digital Signal ◽  
Single Mode ◽  
Hybrid Structure ◽  
Optical Module ◽  
Hybrid Module

In this paper, a machine learning-based tunable optical-digital signal processor is demonstrated for a short-reach optical communication system. The effect of fiber chromatic dispersion after square-law detection is mitigated using a hybrid structure, which shares the complexity between the optical and the digital domain. The optical part mitigates the chromatic dispersion by slicing the signal into small sub-bands and delaying them accordingly, before regrouping the signal again. The optimal delay is calculated in each scenario to minimize the bit error rate. The digital part is a nonlinear equalizer based on a neural network. The results are analyzed in terms of signal-to-noise penalty at the KP4 forward error correction threshold. The penalty is calculated with respect to a back-to-back transmission without equalization. Considering 32 GBd transmission and 0 dB penalty, the proposed hybrid solution shows chromatic dispersion mitigation up to 200 ps/nm (12 km of equivalent standard single-mode fiber length) for stage 1 of the hybrid module and roughly double for the second stage. A simplified version of the optical module is demonstrated with an approximated 1.5 dB penalty compared to the complete two-stage hybrid module. Chromatic dispersion tolerance for a fixed optical structure and a simpler configuration of the nonlinear equalizer is also investigated.

Transmission of 10Gb/s WDM signals over 4000 km of standard single-mode fiber with 106 km spans using all-Raman amplification and NRZ format

2005 ◽  
Author(s):  
Zhangyuan Chen ◽  
Guangquan Wang ◽  
Hong Cen ◽  
Juhao Li ◽  
Lei Zheng ◽  
...  
Keyword(s):  
Single Mode ◽  
Single Mode Fiber ◽  
Raman Amplification

scholarly journals Hybrid EDFA/Raman Amplification Topology for Repeaterless 4.48 Tb/s (40 x 112 Gb/s DP-QPSK) Transmission Over 302 Km of G.652 Standard Single Mode Fiber

2013 ◽  
Vol 31 (16) ◽  
pp. 2799-2808 ◽  
Author(s):  
Juliano Rodrigues Fernandes de Oliveira ◽  
Uiara Celine de Moura ◽  
Getulio Eduardo Rodrigues de Paiva ◽  
Alexandre Passos de Freitas ◽  
Luis Henrique Hecker de Carvalho ◽  
...  
Keyword(s):  
Single Mode ◽  
Single Mode Fiber ◽  
Raman Amplification

scholarly journals Engineering Flat Gain Tunable Raman-Parametric Hybrid L-Band Amplifier for Narrow Band Multi-Channel Terabits System

2019 ◽  
Vol 41 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Gaganpreet Kaur
Keyword(s):  
Optimization Technique ◽  
Single Mode ◽  
Gain Medium ◽  
Single Mode Fiber ◽  
Wavelength Division ◽  
Signal Degradation ◽  
Transmission Distance ◽  
Non Linear ◽  
Flat Gain ◽  
Gain Optimization

Abstract We present a model of a Raman-parametric hybrid amplifier for flat gain amplification of narrowband Dense Wavelength Division Multiplexed (DWDM) terabits capacity system. In the proposed configuration Raman pump has been cascaded with one – pump parametric amplifier. While Raman amplifier typically uses a long length single mode fiber as a gain medium, the Fiber Optical Parametric Amplifiers (FOPA) uses a small length of Highly Non-Linear Fibers (HNLF). This allows for maximum optimization of the gain achieved using Raman as well as parametric processes. We focus on the signal degradation due to non-linear crosstalk arising because of multi-pump configuration, in particular, due to the generated idlers within the operational bandwidth. As the channel spacing is reduced, fiber non-linearities increase significantly. The dilemma to use the fewer number of high powered pumps Vs, the use of increased number of relatively low powered pumps has been investigated for DWDM system. The optimization of the pump powers has been evaluated in terms of signal degradation, gain, gain variation and OSNR. It has been demonstrated that a maximum gain of 45.38 dB for 96×40 Gbps, 25 GHz system is attainable up to 200 km of transmission distance while maintaining OSNR>18 dB using the proposed hybrid. No gain compensation or gain optimization technique has been used. The findings of this work establish flat gain in narrowband DWDM systems is achievable through proper optimization of pump wavelengths and their powers.

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