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Waveguides and Lenses Made by Ion Exchange in Thin Glass Foils

Refractive index profile of buried wave guides in display glass, pitch 250 µm, graded index

Refractive index profile of buried wave guides in display glass, pitch 250 µm, graded index

Process flow of ion exchange from salt melt into thin glass

Process flow of ion exchange from salt melt into thin glass

Sodium ions in glass can be exchanged by metal ions from salt melt causing a refractive index increase in the glass. Depending on the lithographically patterned mask this diffusion process results in waveguides or lenses of different shape, size, length or depth. As special substrate we use thin glass foils (display) and focus on multimode waveguides for optical interconnects. These waveguide foils can be used for new electrical optical circuit boards planar optical couplers or sensors.

Advantages are:

  • low cost due to batch processes
  • low loss waveguides (D263T < 0,1 dB/cm at µm > 800 nm)
  • large panel and buried waveguides possible
  • mechanically and optically stable
  • polarisation independend
  • fiber interconnects are possible by laser fusion