Benchmarking and viability assessment of optical packet switching for metro networks

Optical packet switching (OPS) has been proposed as a strong candidate for future metro networks. This paper assesses the viability of an OPS-based ring architecture as proposed within the research project DAVID (Data And Voice Integration on DWDM), funded by the European Commission through the Information Society Technologies (IST) framework. Its feasibility is discussed from a physical-layer point of view, and its limitations in size are explored. Through dimensioning studies, we show that the proposed OPS architecture is competitive with respect to alternative metropolitan area network (MAN) approaches, including synchronous digital hierarchy, resilient packet rings (RPR), and star-based Ethernet. Finally, the proposed OPS architectures are discussed from a logical performance point of view, and a high-quality scheduling algorithm to control the packet-switching operations in the rings is explained

All-optical phase and amplitude regeneration properties of a 40 Gbit/s DPSK black-box phase sensitive amplifier

We experimentally study the pure amplitude and phase regeneration capabilities of a blackbox degenerate four wave mixing (FWM) based bit-rate-flexible phase sensitive amplifier (PSA) for a 40 Gbit/s differential phase-shift keyed (DPSK) signal

Performance Evaluation of a Reconfigurable Optical Add Drop Multiplexer Design for High-Order Regular and Offset-QAM Signals

In this paper, we investigate the performance of a Reconfigurable Optical Add Drop Multiplexer (ROADM) architecture, that is suitable of supporting high-order regular as well as offset based QAM signals. In the proposed design, a bank of Phase Sensitive Amplification (PSA) subsystems is introduced for processing offset QAM signals, while sub-channel extraction is achieved via waveform splitting and coherent subtraction. Numerical studies have been carried out to validate functional performance, when processing high-order regular and offset based QAM signals

A Reconfigurable OADM Architecture for High-Order Regular- and Offset- QAM based OFDM Super-Channels

We investigate the performance of a Reconfigurable All-Optical Add Drop Multiplexer (ROADM) architecture, that is suitable of supporting high-order regular and offset based QAM signals. The design is based on a highly modular interferometric, structure, in which OFDMA sub-channels remain in the optical domain. Sub-channel extraction is achieved via waveform splitting and coherent subtraction. Numerical studies have been carried out to validate performance and optimize critical parameters of the add/drop process. Particularly, input parameters like the signal extinction ratio, pulse rise time, switching window and input power levels have been optimized for single sub-carrier add/drop operation, from an OFDM super-channel comprising seven optical sub-carriers with 10 GHz spacing. Results have shown that the proposed ROADM architecture can accommodate and process both regular and offset based high-order QAM signals

Equalization performance and complexity analysis of dynamic deep neural networks in long haul transmission systems

We investigate the application of dynamic deep neural networks for nonlinear equalization in long haul transmission systems. Through extensive numerical analysis we identify their optimum dimensions and calculate their computational complexity as a function of system length. Performing comparison with traditional back-propagation based nonlinear compensation of 2 steps-per-span and 2 samples-per-symbol, we demonstrate equivalent mitigation performance at significantly lower computational cost

Information theory analysis of regenerative channels

In this paper we summarize our recently proposed work on the information theory analysis of regenerative channels. We discuss how the design and the transfer function properties of the regenerator affect the noise statistics and enable Shannon capacities higher than that of the corresponding linear channels (in the absence of regeneration)

Sparse Identification for Nonlinear Optical communication systems

We have developed a low complexity machine learning based nonlinear impairment equalization scheme and demonstrated its successful performance in SDM transmission links achieving compensation of both inter- and intra- channel Kerr-based nonlinear effects. The method operates in one sample per symbol and in one computational step. It is adaptive, i.e. it does not require a knowledge of system parameters, and it is scalable to different power levels and modulation formats. The method can be straightforwardly expanded to multi-channel systems and to any other type of nonlinear impairment

Nonlinear Equalization in Long Haul Transmission Systems Using Dynamic Multi-Layer Perceptron Networks

In this paper we investigate the application of dynamic multi-leyer perceptron networks for long haul transmission systems showing performance improvement and significant superiority of neural network complexity over digital back-propagation method

Complex-Valued Kernel-based Phase and Amplitude Distortion Compensation in Parametrically Amplified Optical Links

We develop a complex-valued kernel-adaptive-filtering based method for phase and amplitude distortion compensation in cascaded fibre-optical parametric amplifier (FOPA) links. Our algorithm predicts and cancels both distortions induced by pump-phase modulation across all amplification stages, achieving more than an order of magnitude improvement in BER.Comment: Submitted to European Conference on Optical Communications 2024 (ECOC2024

Wavelength-routed networks with lightpath data interchanges

We observe that tunable wavelength converters (TWCs) that are traditionally installed in wavelength-routed (WR) networks for wavelength contention resolution can be further utilized to provide fast data switching between lightpaths. This allows us to route a data unit through a sequence of lightpaths from source to destination if a direct single lightpath connection is not available or if we want to minimize the overhead of setting up new lightpaths. Since TWCs have a tuning time of picoseconds, it may be possible to use the installed TWCs as lightpath data interchanges (LPIs) to improve the performance of WR networks without significant optical hardware upgrade. Compared with the multihop electronic grooming approach of lightpath networks, the LPI approach has a simpler WR node architecture, does not need expensive high-speed electrical multiplexers/routers, and does not sacrifice the bit-rate/format transparency of data between the source and destination. Our simulation results show that WR networks with LPIs can have much lower blocking probability than WR networks without LPIs if the traffic duration is short. We show that LPIs can also be used to provide new data transportation services such as optical time division multiplexing access (OTDMA) time-slotted service in WR networks. © 2010 OSA.published_or_final_versio