S. Sygletos

Technological challenges on the road toward transparent networking

The sustainable growth of high-bandwidth services and on-demand applications has introduced new challenges to next-generation networks in terms of capacity, configurability, and resiliency. Significant networking advancements need to be achieved with architectures and technologies that are scalable with respect to cost, size, and power requirements, while they should be capable of handling high traffic volumes and dynamically changing connection patterns. Transparent networking has the potential to meet those requirements and offer significant benefits in terms of performance and cost. We present the key enabling technologies, review the state-of-the-art achievements, and discuss the new opportunities that optical transparency has and will introduce.

Linear semiconductor optical amplifiers for amplification of advanced modulation formats

The capability of semiconductor optical amplifiers (SOA) to amplify advanced optical modulation format signals is investigated. The input power dynamic range is studied and especially the impact of the SOA alpha factor is addressed. Our results show that the advantage of a lower alpha-factor SOA decreases for higher-order modulation formats. Experiments at 20 GBd BPSK, QPSK and 16QAM with two SOAs with different alpha factors are performed. Simulations for various modulation formats support the experimental findings.

Single and multiple channel operation dynamics of linear quantum-dot semiconductor optical amplifier

Ultra linear quantum-dot semiconductor optical amplifiers at 1.3 mum provide high dynamic input power range for single and multiple channels with error-free amplification. Good burst-mode tolerance is observed.

2R/3R optical grooming switch with time-slot interchange

We demonstrate a regenerative optical grooming switch for interconnecting 130 Gbit/s and 40 Gbit/s networks with switching functionality in time, space and wavelength domain. Q-factors are above 21 dB.

New Approaches to Perform All-Optical Signal Regeneration

Insights into nonlinear material properties of bulk semiconductor optical amplifiers (SOAs) and novel quantum-dot (QD) SOA nonlinear materials have led to novel device configuration for all-optical wavelength conversion and signal regeneration. The paper will review latest developments and discuss novel configurations.

Investigation of Multi-Wavelength Regeneration Employing Quantum-Dot Semiconductor Optical Amplifiers beyond 40Gb/s

In this paper, we examine for the first time to our knowledge, the potential of all optical regeneration for multiple input wavelengths at bit-rates beyond 40 Gb/s. The system parameters have been investigated assuming two and four channel operation. Successful regeneration has been achieved for two input channels at 40 Gb/s and 160 Gb/s. Four channel operation at 40 Gb/s has been investigated as well, illustrating Q-factor improvement and amplitude fluctuation suppression at the marks.

Optimum filter for wavelength conversion with QD-SOA

High-quality all-optical wavelength conversion is demonstrated with a single QD-SOA followed by a filter. The operation regimes of QD-SOA are identified. It is shown that different filter schemes are needed for the respective regimes.

An Interferometric Configuration for Performing Cross-Gain Modulation with Improved Signal Quality

We introduce and verify experimentally an interferometric scheme for performing cross-gain modulation. The scheme is used to demonstrate all-optical wavelength conversion with good extinction ratio in media with little or no cross-phase modulation nonlinearity.

An all-optical grooming switch to interconnect access and metro ring networks

A novel switch concept is introduced that offers transparent optical grooming of 10 and 40 Gb/s traffic in an access network onto a metro core ring network operated at 130 Gb/s traffic. Key functionalities of the router are the traffic aggregation with time-slot interchanging (TSI) functionality, the TDM to WDM demultiplexing of the high-speed channel into lower bit-rate tributaries as well as multi-wavelength all-optical 2R regeneration of several highest-speed signals.

Multi-Wavelength Regenerative Amplification Based on Quantum-Dot Semiconductor Optical Amplifiers

We discuss the networking potential of the regenerative amplification scheme based on QD-SOAs for both single and multi-wavelength operation at ultra high bit rates. Through numerical modelling the material and device parameters for achieving efficient regenerative performance are identified.