Silica glass sensors 3D-printed on optical fiber

Silica glass sensors 3D-printed on optical fibre

In a first for communications, researchers in Sweden 3D printed silica glass micro-optics on the tips of optical fibre surfaces as small as the cross section of a human hair. The advance could enable faster internet and improved connectivity, as well as innovations like smaller sensors and imaging systems.

Reporting in the journal ACS Nano, researchers at KTH Royal Institute of Technology in Stockholm say integrating silica glass optical devices with optical fibres enables multiple innovations, including more sensitive remote sensors for environment and healthcare. The printing techniques they report also could prove valuable in production of pharmaceuticals and chemicals.

KTH Professor Kristinn Gylfason says the method overcomes longstanding limitations in structuring optical fibre tips with silica glass, which he says often require high-temperature treatments that compromise the integrity of temperature-sensitive fibre coatings. In contrast to other methods, the process begins with a base material that doesn’t contain carbon. That means high temperatures are not needed to drive out carbon in order to make the glass structure transparent.

The study’s 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.

“We demonstrated a glass refractive index sensor integrated onto the fibre 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,” Lai says.

“These structures are so small you could fit 1000 of them on the surface of a grain of sand, which is about the size of sensors being used today,” says the study’s co-author, Po-Han Huang.

A patent application (US 17/171,587) covering the methods and the optical applications in this work has been filed.

Publication: 3D Printing of Glass Micro-Optics with Subwavelength Features on Optical Fiber Tips, ACS Nano, DOI: 10.1021/acsnano.3c11030