Abstract

A novel bidirectional method for the synthesis of highly directional pulses and beams in free space and in complex environments (e.g., waveguides, absorbing media, and plasmas) has been proposed recently.¹ Within the framework of this approach, exact solutions to the wave equation are decomposed into bidirectional, multiplicatively backward and forward, plane waves traveling along a preferred direction z, (e.g., a guide axis). By varying the free parameters associated with the bidirectional source modulation spectrum, localized slowly decaying pulses that move predominantly in the positive z direction can be synthesized. The bidirectional decomposition method has been applied to optical fibers, and the feasibility of synthesizing solutions that can propagate along such structures with only local variations has been demonstrated. Localized wave solutions corresponding to three distinct types of source modulation spectra will be discussed. Distances over which such pulses remain almost nondecaying have been found to be on the order of 1000 km. The bidirectional method of wave synthesis leads to solutions that are capable of countering the dispersive effects introduced by the guiding structure, without invoking the need for nonlinear effects, as in the case of soliton fibers. The feasibility of practical implementation of appropriate source spectra, as well as future research directions, will be discussed.

© 1990 Optical Society of America