Scientists make polymer holey fiber

17 Jun 2002

Australian researchers have created hundreds of meters of easy-to-make polymer-based photonic crystal fiber.

Fiber structure

Researchers from the University of Sydney, Australia, have fabricated photonic crystal fiber based on polymer optical fiber (PC-POF), which they claim is easier to manufacture than glass photonic crystal fiber (Optics Express 9 319).

As with glass photonic crystal fiber, PC-POF has periodic air holes running along its entire length, giving it exotic properties. These air holes confine the light to a central core via a modified form of total internal reflection, rather than the refractive index step of a standard fiber.

Conventional POF is usually multimode and has high losses. PC-POF can not only be made singlemode but also with reduced losses. Martijn van Eijkelenborg said: "At present the fiber is manufactured from a low-quality polymethyl methacrylate (PMMA) and consequently losses in the fiber are high, typically 32 dB/m. But by using pure PMMA this loss can easily be brought down orders of magnitude."

He plans to reduce the loss even further by making a fiber that guides light through an air core rather than the lossy polymer. The group also plans to use a new material which is claimed to give losses down to 2 dB/km, equalling losses reported in glass PC fiber.

Light output

PC-POF is easier to make than glass PC fiber as only one polymer is involved and no dopants are required. This makes it suitable for mass-production. Polymers are also known to maintain their structure throughout the fiber, whereas a collapse of internal structure is sometimes observed in glass PC fiber. Van Eijkelenborg claims that his group has made "hundreds of meters" of PC-POF.

The researchers are supported by Australia-based Redfern Polymer Optics, which will be licensing this technology. Ian Maxwell, CEO of Redfern, said: "We have applied for patents covering this technology. The next step in the project will be to manufacture prototype fiber components and short-haul transmission fiber. Other applications for PC-POF include sensing, medical components and lighting."