Optical Performance Monitoring in High-speed Optical Communication Systems

Ph.DDOCTOR OF PHILOSOPH

Optical differential phase-shift keyed signal generation, transmission and detection

Optical label switching -- Optical performance monitoring -- Multibit delay DPSK demodulation -- OpticalError correction -- FSR optimization -- Free spectral range and optical filtering optimization -- Simulation parameters -- Optical packets -- Performance monitoring -- Multibit delay DQPSK demodulation -- Optical error correction -- Free spectral range and optical filtering optimization

Optical performance monitoring in optical packet-switched networks

Para poder satisfacer la demanda de mayores anchos de banda y los requisitos de los nuevos servicios, se espera que se produzca una evolución de las redes ópticas hacia arquitecturas reconfigurables dinámicamente. Esta evolución subraya la importancia de ofrecer soluciones en la que la escalabilidad y la flexibilidad sean las principales directrices. De acuerdo a estas características, las redes ópticas de conmutación de paquetes (OPS) proporcionan altas capacidades de transmisión, eficiencia en ancho de banda y excelente flexibilidad, además de permitir el procesado de los paquetes directamente en la capa óptica. En este escenario, la solución all-optical label switching (AOLS) resuelve el cuello de botella impuesto por los nodos que realizan el procesado en el dominio eléctrico. A pesar de los progresos en el campo del networking óptico, las redes totalmente ópticas todavía se consideran una solución lejana . Por tanto, es importante desarrollar un escenario de migración factible y gradual desde las actuales redes ópticas basadas en la conmutación de circuitos (OCS). Uno de los objetivos de esta tesis se centra en la propuesta de escenarios de migración basados en redes híbridas que combinan diferentes tecnologías de conmutación. Además, se analiza la arquitectura de una red OPS compuesta de nodos que incorporan nuevas funcionalidades relacionadas con labores de monitorización y esquemas de recuperación. Las redes ópticas permiten mejorar la transparencia de la red, pero a costa de aumentar la complejidad de las tareas de gesión. En este escenario, la monitorización óptica de prestaciones (OPM) surge como una tecnología capaz de facilitar la administración de las redes OPS, en las que cada paquete sigue su propia ruta en la red y sufre un diferente nivel de degradación al llegar a su destino. Aquí reside la importancia de OPM para garantizar los requisitos de calidad de cada paquete.Vilar Mateo, R. (2010). Optical performance monitoring in optical packet-switched networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8926Palanci

On Semiconductor Optical Amplifiers and Optical Coherent Detection

In questa tesi sono affrontate due tematiche inerenti il campo delle telecomunicazioni ottiche: gli amplificatori ottici a semiconduttore e un nuovo tipo di ricevitore ottico coerente. Nel corso della tesi vengono sviluppati nuovi modelli matematici per gli amplificatori a semiconduttore tradizionali e per quelli di tipo gain-clamped. Questi modelli vengono verificati tramite un confronto sperimentale. Infine, tramite una dettagliata verifica sperimentale, vengono confrontate le prestazioni di diverse tipologie di amplificatori a semiconduttore. Il nuovo tipo di ricevitore ottico coerente analizzato nella tesi ricorre all'utilizzo dell'elaborazione numerica del segnale per recuperare le differenze di fase e frequenza tra il segnale ricevuto e l'oscillatore locale che non è agganciato tramite PLL. Una notevole quantità di esperimenti mostra tutti i vantaggi derivanti da questa nuova tecnologia, che permette di recuperare facilmente le distorsioni del segnale dovute agli effetti di dispersione cromatica e dispersione modale di polarizzazione presenti in fibra. Queste potenzialità rilassano enormemente i vincoli di progettazione dei sistemi ottici permettendo di superare i limiti attuali e di aggiornare gli attuali sistemi a 10GBit/s con nuovi sistemi con elevata densità spettrale funzionanti a 40GBit/s e oltre

Towards an Optimal Photonic Network: Optimising Performance, Cost and Flexibility

This thesis investigates optical fibre transmission system technologies, and their impact on network architectures with the objective of lowering unit cost ($/Gb/s/km) of data transmission in long-haul, and ultra long-haul dense wavelength division multiplexing (DWDM) photonic networks. The importance of this work is driven by the exponential growth in Internet traffic of around 40% p.a., and economic pressures constraining network operators’ ability to invest in their networks. Optical transport networks must therefore be designed to meet future bandwidth demands of end users, with optimum performance, cost and flexibility. Dynamic gain equalisers (DGEs) are a key sub-system of ultra long-haul networks, enabling increased un-regenerated transmission reach and elimination of expensive optical-electrical-optical (OEO) regeneration. A theoretical framework was developed integrating models of wideband power variation, together with narrowband nonlinear propagation simulations using the split-step Fourier method. The optimum spacing of the also costly DGEs was determined for a 3,000km network field deployment. Optimum power pre-emphasis profiles were predicted and compared with simple linear calculations, showing <0.7dB performance penalty using the much faster, simplified method. Optical dispersion management schemes were studied, with optical dispersion compensating fibre placed after every other span resulting in 6% cost reduction and little performance degradation compared to compensation after every span. A techno-economic comparison of optical and electronic dispersion compensation (EDC) strategies showed 25% cost reduction using EDC. Tolerance to fibre nonlinearities is reduced compared to optical compensation; splitting the EDC function equally between transmitter and receiver optimises performance. Economic benefits of a single flexible, multi-reach DWDM system were investigated showing almost 20% cost savings compared to separate long-haul and ultra long-haul systems. Finally, the techno-economic benefits of optical bypass in meshed networks were analysed for increasing levels of optical transparency: from OEO regenerated to multi-degree reconfigurable optical add-drop multiplexers (MD-ROADMs), enabling up to 46% cost saving

Coherent wavelength division multiplexing: a novel transmission format for high spectral density optical communication networks

In this thesis a novel transmission format, named Coherent Wavelength Division Multiplexing (CoWDM) for use in high information spectral density optical communication networks is proposed and studied. In chapter I a historical view of fibre optic communication systems as well as an overview of state of the art technology is presented to provide an introduction to the subject area. We see that, in general the aim of modern optical communication system designers is to provide high bandwidth services while reducing the overall cost per transmitted bit of information. In the remainder of the thesis a range of investigations, both of a theoretical and experimental nature are carried out using the CoWDM transmission format. These investigations are designed to consider features of CoWDM such as its dispersion tolerance, compatibility with forward error correction and suitability for use in currently installed long haul networks amongst others. A high bit rate optical test bed constructed at the Tyndall National Institute facilitated most of the experimental work outlined in this thesis and a collaboration with France Telecom enabled long haul transmission experiments using the CoWDM format to be carried out. An amount of research was also carried out on ancillary topics such as optical comb generation, forward error correction and phase stabilisation techniques. The aim of these investigations is to verify the suitability of CoWDM as a cost effective solution for use in both current and future high bit rate optical communication network

Advanced DSP Techniques for High-Capacity and Energy-Efficient Optical Fiber Communications

The rapid proliferation of the Internet has been driving communication networks closer and closer to their limits, while available bandwidth is disappearing due to an ever-increasing network load. Over the past decade, optical fiber communication technology has increased per fiber data rate from 10 Tb/s to exceeding 10 Pb/s. The major explosion came after the maturity of coherent detection and advanced digital signal processing (DSP). DSP has played a critical role in accommodating channel impairments mitigation, enabling advanced modulation formats for spectral efficiency transmission and realizing flexible bandwidth. This book aims to explore novel, advanced DSP techniques to enable multi-Tb/s/channel optical transmission to address pressing bandwidth and power-efficiency demands. It provides state-of-the-art advances and future perspectives of DSP as well

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression