Fimo fractals and fancy fiber

Hollow Core Photonic Crystal FiberEvilmadscientist has a well-documented project on drawing (stretching, not sketching) fimo into fractal patterns. You can start with a set of four triangular rods, stacked together into one larger triangle, strech them out to make them skinny, stack them in with four other similar assemblies, and iterate to make fractals. Aside from the fractal part, this technique is identical to how photonic crystal fibers (PCF) are formed, which got me thinking…

The company website for Crystal Fibre, one of the companies that makes hollow-core photonic crystal fiber, has a nice illustration of the construction process. Shown below, you see that the fiber preform is constructed on a larger scale (several centimeters), with hollow rods stacked hexagonally, and then heated and drawn to a very narrow fiber, with a diameter comparable to the width of a human hair.

Making PCF

So after looking at the fimo fractals, I bet you could do the same thing to make a photonic crystal fiber with fractal structure. Now the question is, would you want to? First, changing the spacing of the crystal, changes the photonic bandgaps so different wavelengths of light would be guided differently. For a typical monochromatic application, that may not be desirable. But for applications to broadband signals or ultra-fast pulses, there may be something interesting there. I’ll have to do some thinking on that.


One thought on “Fimo fractals and fancy fiber

  1. This sounds like an intriguing idea! For 3-D scattering experiments off of fractals, I seem to recall that the scattering strength goes roughly as k^-D, where D is the fractal dimension and k the wavenumber. If something similar holds for fiber propagation, you might have a predictable way of offsetting fiber dispersion: choose a fractal which gives a functional response ‘opposite’ of the fiber dispersion properties.


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