A5039341848- Optical Network Technologies
- Advanced Fiber Laser Technologies
- Advanced Photonic Communication Systems
- Photonic and Optical Devices
- Photonic Crystal and Fiber Optics
- Nonlinear Photonic Systems
- Semiconductor Lasers and Optical Devices
- Advanced Optical Network Technologies
- Advanced Fiber Optic Sensors
- Laser-Matter Interactions and Applications
- Nonlinear Waves and Solitons
- Organic and Molecular Conductors Research
- Physics of Superconductivity and Magnetism
- 2D Materials and Applications
- Molecular Junctions and Nanostructures
- Optical Wireless Communication Technologies
- Quantum and electron transport phenomena
- PAPR reduction in OFDM
- Spectroscopy Techniques in Biomedical and Chemical Research
- Advanced Chemical Physics Studies
- Surface and Thin Film Phenomena
- Advanced Wireless Communication Techniques
- Phase-change materials and chalcogenides
- Nonlinear Dynamics and Pattern Formation
- Acoustic Wave Resonator Technologies
Aston University
2015-2024
Pontifícia Universidade Católica do Rio Grande do Sul
2017
Swansea University
2007-2013
Gower College Swansea
2011-2012
Coventry (United Kingdom)
2003
Stratford Hospital
2002
University of Birmingham
1994
BT Research
1983-1993
BT Group (United Kingdom)
1982-1992
University of Suffolk
1982
A nonlinear device for ultrafast processing is proposed. This based on the propagation in a waveguide loop formed by connecting output ports of conventional coupler. The shown to have potentially useful characteristics unequal coupling ratios and has ability operate entire pulses when soliton effects are included.
The authors examine the formation of stable soliton-like pulses in optical fibres with a periodic dispersion map. It is found that increased energy required to launch pulse given width compared equivalent uniform fibre equal path-average dispersion. shapes managed systems are significantly different hyperbolic secant solitons fibres.
The authors have discovered from numerical modelling that there are stable nonlinear transmission pulses for periodically dispersion managed systems where the path average may be either anomalous, zero, or even normal.
We examine the propagation of solitons in two linearly polarized modes a birefringent fiber. The behavior single is similar to that continuous waves, and nonlinear effects make fast mode unstable when beat length between long. Even with instability, nondispersive pulses can still propagate. High-order break up transfer most energy into single, highly compressed soliton.
We demonstrate, for the first time to our knowledge, switching of optical solitons. observe 93% total reflected energy in a partially transmitting integrated fiber loop mirror that makes up interferometer. This result demonstrates potential solitons as natural bits ultrafast processing.
We propose a novel low-complexity artificial neural network (ANN)-based nonlinear equalizer (NLE) for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) and compare it with the recent inverse Volterra-series transfer function (IVSTF)-based NLE over up to 1000 km of uncompensated links. Demonstration ANN-NLE at 80-Gb/s CO-OFDM using 16-quadrature amplitude modulation reveals Q -factor improvement after 1000-km transmission 3 1 dB respect linear equalization IVSTF-NLE, respectively.
In this paper, we review the historical evolution of predictions performance optical communication systems.We will describe how such were made from outset research in laser based communications and they have evolved to their present form
In this paper, we experimentally demonstrate the benefit of polarization insensitive dual-band optical phase conjugation for up to ten 400 Gb/s super-channels using a Raman amplified transmission link with realistic span length 75 km. We that resultant increase in distance may be predicted analytically if detrimental impacts power asymmetry and mode dispersion are taken into account.
It is shown that the dynamics of optical pulse propagation in lumped amplified systems described by lossless nonlinear Schrodinger equation under condition amplifier spacing short compared to evolution length scale. The errors involved this description are quantified and on order square spacing. authors also consider an alternative method preemphasis which has been proposed, they show how it relates average soliton presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Experiments that produced 100-fsec pulses by a single-pass Raman amplification process did not lead to the expected self-frequency shift induced intrapulse scattering. We show under conditions in which Stokes pulse continues receive frequency-dependent gain from pump, balance can be achieved between two competing processes. Hence progressive of soliton along fiber suppressed.
We present an empirical scaling law that models the increased energy required for launching a soliton into optical system with sections of both normal and anomalous dispersion fiber. It is shown inclusion periodic attenuation amplification can be handled as separate problems, provided interval between amplifiers substantially different from period map. These concepts are illustrated by reference to example comprising dispersion-shifted fiber combined standard
We study the shaping of picosecond-duration optical pulses by intensity-dependent transmission characteristics a fiber loop mirror in normally dispersive region. Experimental results for sech2 intensity input profiles are good agreement with theoretical predictions. In addition, substantial background radiation emerge both compressed and pedestal free.
We describe the two-wavelength operation of nonlinear fiber loop mirror. In this mode a high-power signal at one wavelength switches low-power another wavelength. This device is investigated both theoretically and experimentally. The experimental results show that mirror performs as an optical modulator consists all-fiber components.
We analytically and numerically analyze the occurrence of modulational instability in fibers with periodic changes group-velocity dispersion. For small variations, a set resonances occurs gain spectrum. However, large dispersion variations eliminate these restrict bandwidth fundamental This research has been motivated by adoption management techniques long-haul optical communications.
The all fibre nonlinear optical loop mirror (NOLM) is used in the two wavelength version to show good contrast stable switching of selected pulses from a stream short pulses. polarisation properties device enable operation as genuine four port demultiplexer.
The nonlinear Schrödinger equation (NLS), with its modified forms, is the central for description of pulse propagation in optical fibers. There are a number different physical situations which coupling between waves leads to energy transfer. In such systems, ultrashort pulses have been observed form during propagation. this paper we show that much behavior can be understood by considering effects gain NLS. We also perturbations NLS do not destroy these results, provided possesses...
In this paper we have calculated the effects of loss on propagation soliton solutions nonlinear Schrodinger equation. Since are interested in application these results to optical communications, it is necessary go beyond perturbative results. This due fact that distances fibers significantly greater than decay length energy pulses. Some conclusions drawn about solitons long-distance communications.
Fibre-to-the-premises (FTTP) has promised to increase the capacity in telecommunications access networks for well over thirty years.While it is widely recognized that optical fibre based will be a necessity short medium term future, its large upfront cost and regulatory issues are pushing many operators further postpone deployment, while installing intermediate, unambitious solutions such as Fibre-to-the-cabinet (FTTC).Such high investment of both network core upgrade often derives from poor...
We demonstrate that a combination of Raman laser based amplification and optical phase conjugation enables transmission beyond the nonlinear-Shannon limit. show nonlinear compensation 7×114Gbit/s DP-QPSK channels, increasing system reach by 30%.
We experimentally demonstrate ∼2 dB quality (Q)-factor enhancement in terms of fiber nonlinearity compensation 40 Gb/s 16 quadrature amplitude modulation coherent optical orthogonal frequency-division multiplexing at 2000 km, using a nonlinear equalizer (NLE) based on artificial neural networks (ANN). Nonlinearity alleviation depends escalation the ANN training overhead and signal bit rate, reporting ∼4 dBQ-factor 70 Gb/s, whereas reduction number neurons annihilates NLE performance. An...
Fiber-induced intra- and interchannel nonlinearities are experimentally tackled using blind nonlinear equalization (NLE) by unsupervised machine-learning-based clustering (MLC) in ~46-Gb/s single-channel ~20-Gb/s (middle-channel) multichannel coherent multicarrier signals (orthogonal frequency-division multiplexing (OFDM) based). To that end, we introduce, for the first time, hierarchical fuzzy-logic C-means (FLC)-based optical communications. It is shown among two proposed MLC algorithms,...
We examine the behavior of solitons in optical fibers where dispersion is alternated between normal and anomalous regimes. The periodic nature system strongly modifies shape stable soliton (solitary wave) pulses, increases their energy when compared with equivalent uniform fibers. Power enhancement factors up to 70 are numerically observed. This leads both an increased signal-to-noise ratio (SNR) at receiver reduced Gordon-Haus timing jitter. interaction pairs isolated pulses examined. also...
The authors show that the Gordon-Haus jitter experienced in an optical fibre soliton system is reduced by periodic dispersion compensation. Not only compared with uncompensated fibre, but it lower than of a constant equal to path average managed system.