Scientists Create Wood Based Bio Degradable Fibre Optic Cables

Well this is an odd but interesting one. A team of VTT scientists from Finland have successfully transmitted light over a new type of wood-based optic fibre cable, which has a core that is made from cellulose and this has the added advantage of being biodegradable.

Admittedly this probably isn’t the sort of fibre that you’d want for building a modern glass or plastic-based “full fibre” broadband ISP network, not least since those need to last several decades and deliver optimal performance (this is a long way from that). Nevertheless a wood-based fibre might be useful in sensitive environments and they could also be used to help detect changes in the moisture levels of buildings.

The core of the new optical fibre is made of cellulose, modified for the purpose using ionic solvents developed by VTT. “Around the core, we made a cladding out of cellulose acetate. The R&D is still in its initial phases, so we do not yet know all the applications the new optical fibre could lend itself to,” says BTT’s Senior Scientist Hannes Orelma.

Apparently light is able to travel in the fibre because the core is surrounded by cladding material with a lower index of refraction (i.e. light is reflected back into the core from the interface of the core and the cladding). However so far this has only been tested using a length of fibre that was just a few centimetres long.

The team says that cellulose has properties making it suited for use in optical fibre sensors. For example, the material can in itself react with the substances being measured and absorb them, which is “difficult” for glass or plastic fibres (yes.. generally network builders wouldn’t want their optic fibres to do this).

“Cellulose is also easy to modify as regards, for instance, the index of refraction. Cellulose effectively absorbs and releases water, which can be measured by the change in the attenuation of light transmitted in the fibre. In addition, cellulose is biodegradable, and the fibre used for the sensor can be disposed of with biowaste,” said the team. Further details can be seen in their research paper.