Project DWEA1:

Layout and 3-D Visualisation Tools for Photonic Devices and Integrated Circuits

The growing technological importance of photonic devices and systems, particularly in the area of telecommunications, has led to a demand for component integration, to achieve simultaneous reductions in costs and increases in reliability.  Software packages are needed for computer-assisted design of photonic circuits comprising active devices like devices optical amplifiers, switches and photodetectors and optical waveguides (which have the same function a metal inter-connect in an electronic I.C.) and mirrors.  The properties of optical waveguides are critically dependent on geometry, the materials used in their fabrication and on the polarisation state of the light.  As a consequence, software for photonic circuit layout needs to take into account these factors.

        The objectives of this project include some, or all, of the following

(i)             To develop design tools for optical waveguides for interconnects in photonic integrated circuits, possibly from existing software;

(ii)           To develop a reliable user interface for data entry, possibly including establishing a database of frequently used parameters and structures, integrated with the waveguide design procedures;

(iii)          To develop 2-D and 3-D data presentation formats, for data entry and checking as well as for presenting results;

(iv)          To develop a package for 2-D layout of photonic circuits, to include error checking for breaches of layout rules.  These rules will be applications-based in that device and component dimensions and spacing will depend on the design and performance criteria set for the circuit.

In all the above objectives the need for users to visualise data (input as well as output) is important.  Existing, commercially available packages may be utilised where appropriate.  In addition users will need reliable rapid methods for data entry, for checking its validity and, ideally, inter-active methods of correcting or updating the input data (by picking-up and dragging features?).  This project will unavoidably involve a degree of numerical computation.


Project originator: D.W.E. Allsopp, email eesda@bath.ac.uk


Project DWEA2:

Analysis and Visualisation of Electrokinetic behaviour of Microbiological Particles

        Microbiological particles (e.g.: bacteria, viruses, DNA fragments etc) can react to applied electric fields by moving or rotating in a predictable manner.  The induced motion can be characteristic of a specific particle, thereby enabling its identification or isolation from other species without using time-consuming techniques like culture formation.  The potential advantages of using electrokinetic effects in the analysis of microorganisms in health care, in environmental science and in microbiology are therefore enormous.

        The electrokinetic response of a small particle can be predicted using theory based on certain well-established principles of electronic engineering, namely electrostatics and electromagnetics.  The objectives of this project include


(i)             Developing a programme for calculating and displaying the 3-D electric field distribution for user-defined electrode configurations;

(ii)           Calculating the time dependent response of electrically neutral and charged particles of different geometry to the resulting electric field distributions;

(iii)          Developing software for plotting the time-dependent motion of single particles and small collections of particles within the defined structures, thereby enabling visualisation of their electrokinetic behaviour.

(iv)          If time permits, extending the model to include hydrodynamic effects and Brownian motion, both of which tend to counteract and randomise the electrokinetic motion.

This project will necessarily involve a significant amount of numerical computation.


Project originator: D.W.E. Allsopp, email eesda@bath.ac.uk



Project DWEA3:

Novel method of simulating the propagation of guided lightwaves

Optical fibre networks form one of the main application areas for digital communications techniques.  The increasing sophistication of lightwave components for such networks has created a demand for improved methods of simulating their light guiding properties, to ensure good design and to enable technology advances.  The aims of this project are to develop a novel but intuitive numerical procedure for solving the paraxial wave equation in three dimensional dielectric optical waveguide structures and apply it to the design of a novel multimode photonic device.   Knowledge of MATLAB and/or C or Fortran and an interest in engineering applications of numerical computation are essential for this project.


Project originator: D.W.E. Allsopp, email eesda@bath.ac.uk


Project DWEA4:

Optical filters for advanced optical communications systems

Description:    The information carrying capacity of an optical communications network can be greatly increased by sending different messages simultaneously using different wavelength carriers.  Optical filters are needed at system nodes to add or drop selectively a particular carrier, thereby routing messages through the network.  This is the first of two projects on optical filters and involves developing a computer model to test some novel strategies for realising add/drop filters. 

Objectives:     Investigate the different strategies used in optical fibre systems for realising narrow pass-band optical filters.  Develop a computer model for one of these strategies.  Simulate the performance of various filter structures, thereby identifying suitable integrated optoelectronic device strategy for advanced optical fibre systems.

Resources:      Access to the University computer network or a high performance PC.

Project originator: D.W.E. Allsopp, email eesda@bath.ac.uk


Project DWEA5:

Design of dielectric mirrors and optical cavities

Integrated mirrors form an essential part of several optoelectronic devices. A laser is an example in which a medium providing optical gain is sandwiched between other layers of dielectric material, which act as mirrors.  These then reflect light beams of growing intensity back through the gain region to increase the output power.  Dielectric mirrors can be made up of pairs of transparent layers having different refractive index, to allow vertical integration of optoelectronic components into more advanced structures.  The aim of this project is to establish flexible software for designing individual dielectric mirrors. Thereafter, the project may follow one of several routes. One possibility is to fabricate some mirrors in our own clean room to a studentŐs design, and then characterise their performance. Alternatively, the software can be extended to predict the properties of more complicated structures involving several dielectric mirrors, or predicting how imperfections in their fabrication degrade their performance.


Output:  Develop software for designing dielectric mirrors, fabricate and characterise such mirrors; extend the software to predict the properties of resonant cavities formed by pairs of dielectric mirrors.



Dr D Allsopp

Department of Electronic and Electrical Engineering

12 February 2005