Abstract
It is shown using the scalar diffraction theory that the arbitrary fields guided by optical waveguides can be generated in free space by an appropriate light source. The guided waves can be produced in free space, provided an appropriate launch pattern containing multiple virtual sources can be constructed. In addition, the relation between the guided waves and several particular free-space fields, such as the diffraction-free, soliton-like, self-imaging, ultrashort, partially coherent fields and laser fractals, is demonstrated.