RESEARCH AND DEVELOPMENT

Research and Development
Fibre Design and Analysis
Recent developments in optical preform and fibre fabrication including new techniques in the production of microstructured polymer fibres have necessitated the development of more sophisticated algorithms for analysing specific fibre designs as well as new methodologies for developing novel designs. Several algorithms based on the idea of adjustable boundary conditions have been developed at the OFTC to analyse confinement loss in arbitrary microstructured fibres.The design of a novel fibre is often a multi-objective optimisation problems with simultaneous conflicting criteria and constraints. Biomimetic algorithms inspired by naturally occurring phenomena such as evolution, neural networks and immune systems are been explored at the OFTC to tackle difficult multi-objective problems. Optimisation using evolutionary algorithms mimics the processes of evolution occurring in nature: mutation, recombination and selection. Fibre designs are regarded as structures specified by a set of genes. For example, the genes may represent the geometry (size, shape, placement) of holes in a microstructured fibre, or the chemical dopant profile in a complex MCVD fibre. Each candidate design thus has its own distinct set of genes or genotype. The various optical properties of the device collectively form the traits or phenotype of the candidate design. For example, the traits might include dispersion and spot-size for a fibre design. The phenotype can be calculated from the genotype using appropriate numerical algorithms. The fitness (or figure of merit) for each design is determined by how well the traits achieve the desired performance of the device.