Computational Modelling Group

All-Optical Phase Regeneration of Fiber Optic Communication Signals

Peter Horak (Investigator), Graham Hesketh

All-optical phase regeneration uses a process known as four-wave mixing in a nonlinear optical fiber to carefully mix light with a communication signal in such a way that it cancels transmission noise in the the signals phase, increasing the distance over which the signal can be transmitted. New regenerator designs are presented that suppress phase to amplitude noise conversion and performance is simulated using a supercomputer to assist experimental investigation.

Cavity-Mediated Cooling

Peter Horak, Timothy Freegarde (Investigators), Andre Xuereb

Optical resonators enhance the interaction of light with matter while simultaneously acting as a temporal buffer. Both effects can be exploited to generate light-induced friction, or cooling, forces on atoms, molecules, or micromirrors. We investigate various aspects of these effects through numerical simulations, assisted by approximate analytical models, in this EPSRC and ESF sponsored project.

Centre for Doctoral Training in Next Generation Computational Modelling

Hans Fangohr, Ian Hawke, Peter Horak (Investigators), Susanne Ufermann Fangohr, Thorsten Wittemeier, Kieran Selvon, Alvaro Perez-Diaz, David Lusher, Ashley Setter, Emanuele Zappia, Hossam Ragheb, Ryan Pepper, Stephen Gow, Jan Kamenik, Paul Chambers, Robert Entwistle, Rory Brown, Joshua Greenhalgh, James Harrison, Jonathon Waters, Ioannis Begleris, Craig Rafter

The £10million Centre for Doctoral Training was launched in November 2013 and is jointly funded by EPSRC, the University of Southampton, and its partners.

The NGCM brings together world-class simulation modelling research activities from across the University of Southampton and hosts a 4-year doctoral training programme that is the first of its kind in the UK.

Computational electromagnetic modelling of 3D photonic structures

Marc Molinari, Darren Bagnall, Simon Cox (Investigators), Asa Asadollahbaik, Elizabeth Hart

Nano-structured materials can provide very specific and often very special optical effects which can be exploited for a large range of optical applications including wavelength filters, LEDs, micro-lasers, HDTV, solar-cell coatings, optical high-Q fibres, diffraction gratings, polarisation devices, optical switches, etc. This research in “Computational Electromagnetic Modelling of 3D Photonic Structures” aims to address the need for accurate and fast three-dimensional modelling, simulation and analysis processes in the photonics industry. A FEM/FDTD software suite will be developed to simulate Maxwell’s field equations and thin-film quantum effects (plasmons) in the visible and near-infrared EM frequency spectrum. The results obtained from running the software on suitable compute clusters will then be compared to the analysis results of experimentally manufactured materials. We will investigate structures occurring in nature such as iridescent butterfly wings, white/black reflecting beetle shells, etc., and aim to optimise artificially designed structures with periodic, quasi-periodic and random configurations.

Continuously Tunable Optical Buffer

Peter Horak (Investigator)

The project aims to design, fabricate and test a novel integrated all-optical buffer device that is based on MEMS technology and provides a continuously tunable delay for optical pulses over a broad wavelength region. Such a device could play a crucial role in future packet-switched optical networks, photonic integrated circuits and coherent light based applications such as optically steered phase array antennas, LIDAR and optical coherence tomography.

This EPSRC funded project is a collaboration between the Optoelectronics Research Centre, Southampton, and University College London.

Dynamics simulations for quantum feedback to steer a single-particle harmonic oscillator in non-classical states

Hendrik Ulbricht (Investigator), Ashley Setter

This PhD project is about using digital electronics to implement a parametric feedback loop to modulate the intensity of an optical trapping laser in order to stabilise/cool the centre of mass motion of a nanoparticle. It is then intended we use digital parametric feedback to drive the motion of the particle, which is essentially a quantum harmonic oscillator, into non-classical quantum states such as squeezed and number states.

Efficient algorithms for liquid crystal alignment

Giampaolo D'Alessandro, Timothy Sluckin (Investigators)

We have developed an efficient algorithm to determine the liquid crystal alignment in the absence of defects. The aim of this project is to extend this algorithm to include defects.

Measuring biomolecules - improvements to the spectroscopic ruler

Pavlos Lagoudakis, Tom Brown (Investigators), Jan Junis Rindermann, James Richardson

The spectroscopic ruler is a technique to measure the geometry of biomolecules on the nm scale by labeling them with pairs of fluorescent markers and measuring distance dependent non-radiative energy transfer between them. The remaining uncertainty in the application of the technique originates from the unknown orientation between the optical dipole moments of the fluorescent markers, especially when the molecule undergoes thermal fluctuations in physiological conditions. Recently we introduced a simulation based method for the interpretation of the fluorescence decay dynamics of the markers that allows us to retrieve both the average orientation and the extent of directional fluctuations of the involved dipole moments.

Meshless Methods for Photonic Crystal Modelling

Kamal Djidjeli, Marc Molinari, Simon Cox (Investigators), Neil O'Brien, Elizabeth Hart

We apply meshless methods to the problems of simulating photonic crystals. The meshless methods utilise compactly-supported radial basis functions (CSRBFs) and offer a promising alternative to the conventional plane-wave expansion method for calculating the band structure of photonic crystals.

Multimode simulation of high power fibre lasers and amplifiers

Peter Horak (Investigator), Ioannis Begleris

This project aims to address the challenge of ever-increasing demand for higher powers from fibre lasers by developing theoretical and numerical methods to simulate laser pulse amplification in large-mode area fibres supporting multiple spatial modes.

Nonequilibrium Dynamics of Atomic Gases in Optical Lattices

Sophie Marika Reed

Many-body, quantum systems exhibit emergent properties which allows for quantum events to influence properties on macroscopic scales. Such emergent properties are studied using stochastic phase-space techniques.

Nonlinear Optical Pulse Propagation

Peter Horak, Francesco Poletti (Investigators)

The work is concerned with the propagation of high-power short-pulse propagation in microstructured fibres or waveguides. Dispersion properties and optical nonlinearities are exploited for pulse shaping techniques in space, time, and frequency. Investigated microstructures include silica or soft-glass templates, gas-filled capillaries, and semiconductor-filled fibres, and optical wavelengths range from the X-ray to the mid-infrared regime.

Nonlinear Optics in Structured Material

Peter Horak, Neil Broderick (Investigators)

Structured materials such as photonic crystals, optical fibres, Bragg gratings etc. are the ideal material for nonlinear optics. Properly engineered materials allows one to control which nonlinear interactions are observed and enhanced whilst other nonlinear interactions can be neglected. This work looks both at fundamental ideas as well as the fabrication of devices for advanced telecommunications.

Soft x-ray science on a tabletop

Peter Horak, Jeremy Frey, Bill Brocklesby (Investigators), Patrick Anderson, Arthur Degen-Knifton

Complex numerical simulations are being performed to aid experimentalists at Southampton realize the next generation of high brightness tabletop sources of coherent soft x-rays.?

Today's Computation Enabling Tomorrow's Seamless Communication

Lajos Hanzo (Investigator), Varghese Thomas

Radio Over Fibre (ROF) is a communication technique that aims to gainfully amalgamate the benefits of optical and wireless communication, while keeping the system cost low. This technique would support the next generation of wireless services.