Photonic crystal fiber

[androz]

Hi,
Can someone tell me how a wave is guided (in a fiber for instance) thinking
in term of diffraction (or scattering) and not in term of successive
reflections.
And my second question is : would it be possible to "extrude" a plan
diffractive element in a fiber to guide wave and have the right diffractive
motion at the end of the "diffractive fiber" ?

[pallidin]

Could you rephrase/expound on your second question? I'm not understanding it.

[androz]

Well,
Imagine you want a particular field pattern, a particular laser beam shape.
It is possible to use holograms or SPM to "create" a multifocus tool, ie
a sort of lattice of light spots for instance, or a particular beam shape
such as Laguerre-Gauss laser beams.
My question was : would it be possible to put a third dimension to this SPM or hologram, just like an optical fibre, in order to guide a wave, and have the desired field at the end of the fiber, such as a Bessel beam, or a Laguerre-Gauss beam....
I was thinking of it just after I read an article of Prof. Canning in
OpticsExpress this month about the so-called "Fresnel-fiber".