Júlio C. R. F. Oliveira

EDFA adaptive gain control effect analysis over an amplifier cascade in a DWDM optical system

In this paper, we analyze the EDFA adaptive gain control impact on 80 modulated C-band channels (10 Gbps NRZ) in a DWDM optical system composed of four cascaded amplifiers. System performance was evaluated in terms of channels optical signal-to-noise ratio (OSNR), noise figure (NF), bit error rate (BER), and gain flatness (GF) measurements. The adaptive EDFA scheme aims to optimize NF and GF spectra by adjusting its setpoint gain based on static information about these parameters and was improved here to prioritize NF when BER of the received signal remains under the FEC limit.

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

In this work we carry out a comprehensive experimental study on hybrid optical amplification topologies (based on first order Raman and Erbium doped fiber amplifiers) for repeaterless transmission of 112 Gb/s dual polarization-quadrature phase shift keying (DP-QPSK) enabling a 4.48 Tb/s (40 × 112 Gb/s) transmission over 302 km of standard single mode fiber with coherent detection. Hybrid optical amplification was employed for signal boosting and pre-amplification and repeaterless transmission is assured without the use of neither in-line amplification nor remote optical amplifiers. The goal was to achieve the highest bandwidth-distance product for repeaterless DWDM transmission systems over legacy fiber without any in-line amplification technology. The achieved result is a significant milestone, when compared to recent state-of-the-art investigations.

Global WSS-based equalization strategies for SDN metropolitan mesh optical networks

We experimentally demonstrate the benefits of global (end-to-end) WSS-based spectrum equalization for multiple ROADMs in cascade. We introduce three equalization strategies to enable OSNR enhancement in a SDN metropolitan mesh optical network test-bed with 80 × 128 Gb/s.

Towards software defined autonomic terabit optical networks

This paper presents an Optical SDN architecture and implementation enabled for virtual optical networks, supporting adaptive and cognitive algorithms to enhance QoT. The paper also shows experimental results of a software-defined autonomic flexible transponder.

Global ROADM-Based Spectrum Equalizer in SDN Architecture for QoT Optimization at DWDM Networks

We introduce a global (end-to-end) ROADM-based spectrum equalizer algorithm running over DWDM networks on SDN architecture. Significant OSNR improvements are experimentally demonstrated for a DWDM coherent 80×112Gb/s system compared with local equalization schemes.

Flexible optical transmission systems for future networking

This paper describes the path for future implementations of flexible optical transmission. The baseline discussion is divided into the transponder technical aspects and the network subsystem elements. Regarding flexible transponder, three degrees of freedom such as modulation format, symbol rate and number of channels are exploited in order to obtain rate adaptive transmitters and receivers. In addition, digital signal processing is discussed to relax the hardware resources and to enhance transmission performance. As far as the optical networking is concerned, some functionalities present in node subsystems as optical amplifiers and filters in reconfigurable optical add/drop multiplexers (ROADM) / wavelength selective switches (WSS) are optimized and implemented to support the requirements needed in software defined networks (SDN).

Hybrid distributed Raman/EDFA amplifier with hybrid automatic gain control for reconfigurable WDM optical networks

Nowadays, optical amplifiers designs are induced by new requirements generated by optical networks. The introduction of WDM reconfigurable networks with increasing rate from 10-40 Gb/s to 100 Gb/s and beyond, demand new optical amplifiers development with improved gain spectral flatness and noise figure for all operational range of input powers and set-point gains. In this paper, it was developed a hybrid distributed Raman/EDFA amplifier with a novel hybrid gain control (HGC) scheme based on joint actuation. The HGC was firstly developed by numerical simulation and after experimentally, in a WDM system with 100 km SSMF fiber span and full C-band load. The Results shows an improved equivalent noise figure with flattened gain spectrum for all amplifier operation range in dynamic optical networks.

Triple Band Silica Based Double Pass EDFA with an Embedded DCF Module for CWDM Applications

We present a double pass triple-band EDFA with an embedded DCF experimentally characterized over the CWDM grid. It is shown that the amplifier can extend the bus topology link length beyond the 100 km limit

Multidimensional optimization of optical spectral shaping for fiber nonlinearities mitigation in high baud-rate systems

We experimentally demonstrate a multidimensional global optical spectral shaping optimization based on genetic algorithm for fiber nonlinearities mitigation in a 56-GBd PDM-QPSK transmission system. The proposed method increased maximum reach by 24%, reducing transmission penalties by up to 1.8 dB.

WDM transmission of 3×1.12-Tb/s PDM-16QAM superchannels with 6.5-b/s/Hz in a 162.5-GHz flexible-grid using only optical spectral shaping

We demonstrated the transmission of 3×1.12-Tb/s superchannels (5×224-Gb/s PDM-16QAM) in 162.5-GHz flexible-grid, 6.5-b/s/Hz SE, using only optical spectral shaping, over SSMF-EDFA link. A maximum reach of 600-km with 3-ROADM passes was obtained employing nonlinear compensation.