Semiconductors grown in optical fibres

Researchers from

in the

and the

have found a way to grow tiny semiconductor devices inside optical fibres.

Microstructured optical fibres have a nanoscale channel running through them that have the same dimensions as the wavelength of light. The channels act as a guide, radically changing the refractive index.

The new research involves growing semiconductor crystals inside the channels which could lead to the creation of new detectors and laser diodes. This would present a major advantage for communications.

Pier Sazio, senior research fellow in the Optoelectronics Research Centre at the University of Southampton met John Badding, associate professor of chemistry at Penn State when he was in the UK on sabbatical. Together they had the idea to build semi-conductor device technology inside the “holey fibres”. Their continued work was made possible through the World University Network’s Global Exchange Programme.

“The whole concept of what we’re doing is to borrow techniques from the semiconductor industry to circumvent the need to pigtail external devices,” said Sazio. “So far we have achieved modulation, switching and amplification, all inside the fibre.”

The researchers used chemical vapour deposition (CVD) to deposit germanium and other semiconductors inside the pores of the optical fibres. A germanium compound is vaporised and forced into the tube at a high pressure and temperature. A chemical reaction allows the germanium to coat the interior and form crystals which grow inward.

Sazio said they have managed to build metre-long structures which could change the future of electro-optic devices. “Normally light interacts over chip-scale devices, but we’ve made it work over a metre length of optical fibre.”

He went on to say that as in the early days of semiconductor technology, the next step is for material quality to go up.