KTH Sweden develops 3D printed silica glass micro-optics on fibers…

21 May 2024

…and UK’s EPSRC awards £1.2 million grant to Aston’s Picometer Surface Nanoscale Axial Photonics project.

3D printing 1,000 times smaller than a grain of sand.

In what is described as “a first for communications”, researchers in Sweden have 3D printed silica glass micro-optics on the tips of optic fibers. They say that the advance could enable faster internet and improved connectivity, as well as innovations like smaller sensors and imaging systems.

The scientists at KTH Royal Institute of Technology in Stockholm say integrating silica glass optical devices with optical fibers enables multiple innovations, including more sensitive remote sensors for environment and health care. The printing techniques they report also could prove valuable in production of pharmaceuticals and chemicals.

The work is described in the journal ACS Nano.

KTH Professor Kristinn Gylfason says the method overcomes longstanding limitations in structuring optical fiber tips with silica glass, which often require high-temperature treatments that compromise the integrity of temperature-sensitive fiber coatings.

In contrast to other methods, the process begins with a base material that does not contain carbon. That means high temperatures are not needed to remove carbon in order to make the glass structure transparent. Lead author Lee-Lun Lai says the researchers printed a silica glass sensor that proved more resilient than a standard plastic-based sensor after multiple measurements.

Printing process and example 3D structures in glass. Click for info.

New applications

“We demonstrated a glass refractive index sensor integrated onto the fiber tip that allowed us to measure the concentration of organic solvents. This measurement is challenging for polymer-based sensors due to the corrosiveness of the solvents,” said Lai.

Study co-author, Po-Han Huang added, “These structures are so small you could fit 1,000 of them on the surface of a grain of sand, which is about the size of sensors being used today.”

The researchers also demonstrated a technique for printing nanogratings, ultra-small patterns etched onto surfaces at the nanometer scale. These manipulate light in precise ways and have potential applications in quantum communication.

Gylfason says the ability to 3D-print arbitrary glass structures directly on a fiber tip opens new frontiers in photonics. “By bridging the gap between 3D printing and photonics, the implications of this research are far-reaching, with potential applications in microfluidic devices, MEMS accelerometers and fiber-integrated quantum emitters,” he said.

Aston receives £1 million to ‘revolutionize’ mini optical devices

Meanwhile, researchers at Aston University, Birmingham, UK, have received more than £1 million ($1.27 million) to develop optical devices that are so small they would also fit on the surface of an optical fiber. Potential applications are in manufacturing, IT and agriculture.

The £1,167,290 grant has been given by the UK’s Engineering and Physical Sciences Research Council (EPSRC) for the Picometer Surface Nanoscale Axial Photonics (PicoSNAP) project. The award will be used to develop Surface Nanoscale Axial Photonics (SNAP) technology which enables the fabrication of miniature photonic devices.

Picometer-scale optical devices.

Traditionally, the precision of microscopic devices has been constrained by the size of atoms, with fabrication technologies plateauing at several nanometers. However, PicoSNAP technology, which was pioneered by Professor Misha Sumetsky of Aston Institute of Photonic Technologies (AIPT), has enabled devices to be scaled down even further so they can be measured in picometers.

Prof. Sumetsky is aiming to develop a reliable manufacturing process to enable production of the devices that is both ultra-accurate and easy to reproduce. If successful, the project will not only bring in a new revolutionary technology but also deliver miniature optical devices with performance not previously possible to achieve, and ready for practical applications.

He said, “The lack of reliable, scalable manufacturing processes with picometer precision remains a major obstacle, and SNAP technology has the potential to address this need with its exceptional precision and performance. “The goal of this project is the development of the process, which requires insight into the depth of associated physical phenomena, as well as the design and fabrication of new micro devices critical for the future communication, optical signal processing, microwave and sensing technologies.”