This would not only reduce fabrication and material costs but also lower labor costs because training and hazards are reduced.” “With further improvements to limit the light losses, this new approach could potentially replace the conventional lathe-based method of making silica optical fibers. “The new technique worked surprisingly well and can be applied to a range of glass material processing to improve other types of optical components,” said Canning. Although they did observe high light losses in the initial fabricated optical fibers, they have since identified the causes for these losses and are working to address them. The researchers used their new technique to fabricate a preform equivalent of a standard germanosilicate fiber that could be used to create multi- or single-mode fibers, depending on drawing conditions. Finally, raising the temperature further fused the nanoparticles into a solid structure that could be inserted into a draw tower where it is heated and pulled to create the optical fiber. Next, the researchers used a unique heating step called debinding to remove the polymer and leave behind only the silica nanoparticles, which are held together by intermolecular forces.

In this way, the integration of a range of dopants becomes possible. They then inserted a similar mix of polymer and nanoparticles into the hole, this time adding germanosilicate to the silica nanoparticles to create a higher refractive index. They designed a 3D printed cylindrical object that contained a hole for a core. To create a silica object, the researchers added silica nanoparticles into the monomer at amounts of 50 percent or greater by weight. This type of additive manufacturing is extremely precise and typically used to create polymer objects by using a digital light projector to polymerize photo-reactive monomers. In the new work, the researchers used a commercially available direct-light projection 3D printer. “We expect this advance to bring a flurry of activity, including other additive manufacturing approaches, to accelerate this field.” “Thanks to a novel combination of materials and nanoparticle integration, we have shown it’s possible to 3D print a silica preform,” said Canning. Applying this approach to silica has proved challenging due to immense material challenges including the high temperatures – more than 1900 degrees Celsius – needed to 3D print glass. The new achievement builds off earlier work in which the researchers used a polymer material to demonstrate the first fiber drawn from a 3D printed preform. “This could, for example, broaden the applications of fiber optic sensors, which far outperform electronic equivalents in terms of longevity, calibration and maintenance but haven’t been widely deployed due to their expensive fabrication.” “Additive manufacturing approaches such as 3D printing are well suited to change the entire approach to fiber design and purpose,” said Canning. In The Optical Society ( OSA) journal Optics Letters, Canning’s group in collaboration with Gang-Ding Peng’s research team at the University of New South Wales in Sydney report the first silica glass fibers drawn from 3D printed preforms.

The orange inset shows a cross section of a step index fiber.Ĭredit: John Canning, University of Technology in Sydney

These preforms were then placed in a draw tower (middle picture) to make the final optical fiber (right). They fabricated preforms for a step index fiber (a) and a structured preform (b). Caption: Researchers used a 3D printing method known as direct-light projection (DLP) to make silica fiber preforms.

Glass preform