Sculpting glass with light for future fibre optics

For 50 years, glass optical fibres have been a cornerstone of telecommunications networks, enabled by ultra-pristine silica glass which can be drawn to fibre with an attenuation of less than 0·2 dB/km. Recently, hollow-core fibres (HCFs), which guide light in air rather than glass, have succeeded the lowest-loss solid fibres for the first time, paving the way for a new era in fibre-optic communication. Offering lower latency and higher bandwidth than solid fibres, HCFs are experiencing a surge recently, driven by developments in AI and cloud networking. Despite this surge, HCFs are limited in design by manufacturing challenges associated with the conventional “stack‐and‐draw” method, whereby glass rods and capillaries are stacked longitudinally to form the fibre preform.

To unlock the full potential of HCFs, we are exploring radically new approaches to manufacturing fibre preforms based on advanced laser processing. In this approach, arbitrarily structured silica discs are laser fabricated and bonded axially to form the preform, which is then drawn to optical fibre using a conventional fibre drawing tower. We hope that this method will enable the manufacture of freeform fibres with unconstrained core-cladding structure.

In my talk, I will give an introduction to ultrafast laser processing of glass and discuss some of the unique capabilities it offers. I will then present our work on the development of freeform optical fibres, and discuss aspects of glass processing including laser processing, chemical etching, glass bonding and fibre drawing.