SLIPPRY combines two very exciting topics in contemporary photonics research - slow light and photonic crystals - with the goal of designing compact and efficient slow light structures for all-optical data processing applications.Slow light will be the key to a new generation of all-optical processing devices including optical delay lines and buffers as well as ultra-compact, low power switches and modulators.To be of practical use, these devices must be broadband, and therefore require precise dispersion control in order to process high data rates and short pulses without signal degradation. Photonic crystals are thus the ideal platform for slow light structures, as they exhibit strong and highly adjustable dispersion behaviour as well as being able to operate over a wide bandwidth.One of the major shortcomings of this promising field is the lack of mature designs; while an ad hoc slow light design has recently been demonstrated in a photonic crystal modulator [Vlasov et al. Nature 438, pp.65-68, Nov 200 5], there is much to do in terms of bandwidth, suppression of higher order dispersion terms and tunability of the slowdown factor.SLIPPRY aims to address these issues through the following objectives,- comparative analysis of slow-light mechanisms in photonic crystals;- design and optimization of novel slow light structures;- optimization of an injector for broadband coupling to slow light modes;- design of active slow light devices in photonic crystals.We will achieve these objectives with the implementation of a numerical design and optimization program running in parallel with a world-class experimental research program.The design approach will incorporate semi-analytic methods, two- and three- dimensional numerical simulations and state-of-the-art numerical optimization tools. Refinement of designs will be undertaken in close collaboration with experimentalists to ensure designs are feasible and optimized for experimental conditions.