Researchers have developed an optical fiber composed of wood-based material that can successfully transmit light. The core of the optical fiber is created out of cellulose. According to the team from VTT Technical Research Center of Finland, they initially modified the core to use in a project involving ionic solvents.
“Around the core, we made a cladding out of cellulose acetate,” said Hannes Orelma, lead researcher. “The R&D is still in its initial phases, so we do not yet know all the applications the new optical fiber could lend itself to.”
The very first plastics were based on plant cellulose, though today most plastics are based on hydrocarbon molecules. The VTT researchers studied how cellulose could function as an effective material for optical fibers. Cellulose has properties that can easily react with substances and absorb them. Compared to traditional glass or plastic fibers, this presents more fluidity. Cellulose can also absorb and release water easily. It can be measured by the change in the attenuation of light transmitted in the fiber.
“We have tested the suitability of the fiber for measuring moisture levels,” said Ari Hokkanen, researcher. “Using a length of fiber of a few centimeters, we have already succeeded to increase the attenuation of light transmitted in the fiber many orders of magnitudes.”
Not only that, cellulose can be easily modified with regards to factors such as the index of refraction. It is one of the primary reasons why light is able to travel in the fiber. The core is encompassed with a cladding material that has a lower index of refraction. This means light can be reflected back into the core from the interface between the core and cladding.
Cellulose is also a biodegradable material, meaning the fiber can be disposed of with biowaste.
The team hopes that other researchers will consider cellulose as a material for optical fibers to create new opportunities for sensor applications. However, they expressed that it has more potential in scientific applications and not a competitor with glass-based optical fibers in telecommunication applications.
Development of the optical fiber began in VTT’s iBex program. It is ongoing research and development under the FinCERES flagship program in collaboration with VTT and Aalto University.
The research was published on Nov. 25 in Cellulose. For related news, check out Researcher Develops Wood Cellulose Material Stronger Than Steel.