Slow light with persistent spectral hole burning in waveguides

We model numerically the reshaping of a weak probe pulse propagating in an absorptive, optically dense, persistent spectral hole burning medium under conditions of slow group velocity. Saturated holes are burned in waveguide geometry by illumination in the transverse direction with low absorption, whereas the probing is carried out in longitudinal wave guiding directions with high absorption. We show that by choosing optimum hole spectrum, the Gaussian probe pulse may be delayed by several times its original duration, while overall pulse shape distortion is less than 1% and average energy loss is less than 10%.