New frontiers of the optical fibre manufacturing

The process of optical fibre manufacturing starting from raw material was consolidated long ago, but an innovative method developed by the researchers of Massachusetts Institute of Technology (MIT) might allow a new approach, permitting also a more effective integration of different materials into fibres, with the target of obtaining high-quality fiber-based electronic devices. Initial materials are vitreous silica and aluminium, widely available and usable for various applications, for instance in the construction of windows. They discovered that these two materials react chemically when they are heated and processed together, permitting to obtain fibres with a pure crystalline silicon core, a silica cladding and a subtle layer of aluminium between these two sections. It is worth underlining that this experimental result was absolutely unexpected, a real surprise for researchers who were testing different materials to try to integrate metal wires into the optical fibres, to the extent that they hypothesized an error in the result analysis. They have instead made a discovery: at about 2200°C aluminium reacts with silica and forms silicon oxide, leaving behind pure silicon concentrated in the core, besides an aluminium layer between core and cladding that, moreover, confers sturdiness to the fibre. This result is a first step towards the low-cost creation of electronic devices inside fibres, target already reached by other research teams with various sophisticated methodologies but always starting from extremely pure and very expensive pure silicon. This new “value added processing”, which is allowing the MIT team to experiment the use of different materials, like gold or copper, to create specific structures integrated into fibres, permits to consider optical fibres differently, as elements able to offer much more than the functions made available until now. The low-cost integration of electronics into optical fibres that might be used, then, together with standard textile fibres, for the realization of smart fabrics, is certainly a technological leap of great relevance with effects on the market still completely undiscovered.