Breakthrough technique offers the prospect of silicon detectors for telecommunications

For decades silicon has been the workhorse of the microelectronics revolution and, owing to its excellent optical properties in the near- and mid-infrared range, is now promising to have a similar impact on photonics.

A team of researchers led by the Optoelectronics Research Centre (ORC) has demonstrated a breakthrough technique that offers the first tantalizing possibility of silicon detectors for telecommunications.

The team’s research, reported in the journal Nature Materials, describes the route to engineering the electronic band structure of laser-crystallized silicon photonic devices that helps overcome some of the greatest challenges of using silicon in data communications.

The laser processing technique has been developed for their silicon optical fibre platform. It demonstrates that it is possible to completely crystallize the core material whilst at the same time writing in large stresses to modify the optoelectronic properties, achieving extreme bandgap reductions from 1.11 eV down to 0.59 eV, enabling optical detection out to 2,100 nm.

Incorporating silicon materials within the fibre geometry circumvents the issues associated with coupling between the micron sized fibres used for the transport of light, and the nanoscale waveguides on-chip that are employed for data processing and communications systems.

Dr Anna Peacock, an Associate Professor in Optoelectronics who heads the group in the ORC, comments: “The ability to grow single-crystal–like materials directly inside the fibre core is a truly exciting prospect as for the first time the optoelectronic properties of the silicon fibre devices will be able to approach those of their on-chip counterparts.”

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