Siemens researchers have designed an integrated single-chip fibre-optic receiver which could enable cheap 100Gbit/s Ethernet.

In tests over a 480km loop of fibre, the chip converted optical signals to error-free electronic data at 107Gbit/s. It will cut costs by replacing several optical receiving modules with just one, said Siemens project co-ordinator Dr Rainer Derksen.

Today, the signal on a fibre must be optically split into several slower signals, and each of these converted by a photodiode. Current technology also limits the capacity of each data channel on a fibre to around 40Gbit/s, according to Siemens.

The new chip, which uses silicon-germanium semiconductor technology developed by Infineon, needs only one photodiode and no optical splitters. In addition, Derksen and his team have designed the chip so no separate clock signal is needed - it derives the clock from the main signal.

Derksen added that a major challenge for the Siemens team was that high frequency signals can reflect or oscillate within a chip, so the dimensions of the circuit were critical.

He added that the chip could potentially be combined with dense wavelength division multiplexing (DWDM) to allow a fibre to carry several multiplexed 100Gbit/s channels.

Breaking the 100Gbit/s barrier is vital, as the networking industry looks beyond Gigabit and 10G Ethernet to either 40G or 100G. Siemens said that the first products based on its new chip could reach the switching centres and backbones of network operators in two to three years time.