A team of researchers from the University of New South Wales has developed a new method for making optical glass fiber preforms, the pucks of material that glass fiber optics are drawn from, using DLP 3D printing technology. This breakthrough could not only lead to significant advancements in how fiberoptics are made, and ultimately could result in cheaper, higher-quality fiber optics, but could produce new designs that lead to major advancements in the technology.
“Making silica optical fiber involves the labor-intensive process of spinning tubes on a lathe, which requires the fiber’s core or cores to be precisely centered,” explained John Canning who led the research team from the University of Technology in Sydney. “With additive manufacturing, there’s no need for the fiber geometry to be centered. This removes one of the greatest limitations in fiber design and greatly reduces the cost of fiber manufacturing.”
Image Credit: University of Technology Sydney
Serving as the foundation for this new project, this same team of researchers previously used a 3D printer to create a polymer-based optical fiber preform that was drawn into thin optical fibers as a proof of concept. While this worked with a polymer at normal 3D printing temperatures, the team had to figure out how to print the preforms using optical-grade silica, which needs to be very hot, almost 2000 degrees Celsius, before it melts enough to become printable. The solution was to suspend very small beads of the silica into the photo-reactive monomer resin used in DLP-based 3D printers.
“Thanks to a novel combination of materials and nanoparticle integration, we have shown it’s possible to 3D print a silica preform,” said Canning. “We expect this advance to bring a flurry of activity, including other additive manufacturing approaches, to accelerate this field.”
The team used an off-the-shelf DLP 3D printer and a special resin that contained by weight, 50-percent or more nanoparticles of silica. A cylindrical object with a hole for the optical core was designed and 3D printed, then the optical core hole was filled with a similar mix of the resin and silica nanoparticles, but this time germnanosilicate was also added to increase the core’s refractive index once cured.
“Additive manufacturing approaches such as 3D printing are well suited to change the entire approach to fiber design and purpose,” said Canning. “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.”
Next, the preform undergoes a process called “debinding,” where the polymer is removed, leaving behind nothing but the silica nanoparticles and germanosilicate. The temperature in the kiln is then increased until the nanoparticles are fully fused together into one solid crystalline structure. The preform is then placed on a traditional draw tower and pulled into tiny optical fibers. While this process is still in its infancy, it will allow cheaper optical fibers to be made at a much quicker pace in the future, and it could allow manufacturers to easily create multi-cored optical fibers, thus increasing the data throughput through the same size optical fiber.
“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. “With further improvements to limit the light losses, this new approach could potentially replace the conventional lathe-based method of making silica optical fibers. This would not only reduce fabrication and material costs but also lower labor costs because training and hazards are reduced.”
Major technological advancements such as this really get me excited because of their potential to change life on earth as we know it. 3D printing has revolutionized so many areas of technology, and as more research like this is published, the future for 3D printing looks more promising than ever before. If you have followed my writings here at Element14 over the years you will know that I am a major proponent of 3D printing, and spent a significant portion of my post-college 20’s working on DIY 3D printer designs during the early days of the RepRap project, and advancements like this just rekindle that fire for me.