Abstract: Optical guiding of intense laser pulses over a distance of more than one Rayleigh length in a plasma is discussed herein using a multi-pulse technique. The first pulse or pulse sequence prepares a shock-driven, axially-extended radial electron density profile which guides a second pulse or sequence of pulses. The profile is also capable of guiding x-rays. The channel will support mode structure exactly analogous to that of an optical fiber waveguide. The method provides a means for guiding of a high intensity optical laser pulse or x-rays over distances well in excess of a Rayleigh length. The distances over which guiding occurs is limited only by the length of the preformed plasma and absorption and possible backscattering of the guided EM radiation. Applications of the method allow for compact x-ray laser devices and electron particle accelerators.