There exists a well known analogy between paraxial or one-dimensional Fresnel diffraction and the propagation of pulses in linear dispersive medium with negligible attenuation. Under this analogy, the envelope of a pulse is equivalent to the distribution of complex amplitude of the light in diffraction. In this context, we study the propagation of a train of identical Gaussian chirped pulses arranged in time in the same way as the Fresnel zones of a phase zone plate, in a highly dispersive guiding medium. From this study we find that the input train concentrates into a single pulse for certain values of total dispersion. We establish the focusing condition and characterize the output signal through its width and peak intensity, showing their dependences on the parameters that define the input train and the dispersive device.