Plastic fantastic for Siemens

5 June 2007

Researchers at Siemens Corporate Technology have succeeded in transmitting data at a rate of one gigabit per second through optical polymer fibre cables, setting a new record

Researchers at Siemens Corporate Technology have succeeded in transmitting data at a rate of one gigabit per second through optical polymer fibre cables, setting a new record.

A new data transmission technique allowed the fast rate, which is ten times faster than with products currently on the market. This performance sets the stage for the use of polymer cables in home entertainment and factory automation.

In polymer fibre cable transmission, small converter boxes convert the electrical signal from the copper cable into an optical signal and thin plastic cables transport the optical signal to receivers. Because of the very high transmission rate of these polymer fibre cables, television signals with high data volumes could also be transmitted within the home in this way in the future.

Until recently, polymer fibres’ transmission capacity has been limited to 100Mbit/s, sufficient for DSL but not enough for internet telephony and television, which require closer to 1Gbit/s.

To obtain a fast, reliable transmission, the Siemens researchers applied an algorithm that changes the light signals in such a way that more information fits into the available bandwidth of the polymer fibres. They adapted the familiar multi-carrier modulation technique used in DSL and WLAN so that it is also applicable to light signals.

‘Thanks to quadrature amplitude modulation with up to 256 signal states, the so-called bandwidth efficiency measured in bits per second and hertz can be increased significantly,’ said Sebastian Randel, project manager at Siemens Corporate Technology. Using the algorithm, the researchers could transmit exactly 1008Mbits/s through a polymer fibre cable.

This makes the polymer fibre suitable for use in the home and for industrial automation applications where the rugged, low cost cables have long been established as the standard. They are used to connect machine tools or robots together and to link them to the central control unit.

Randel sees even more potential applications for high-speed polymer fibres, for example in the automotive industry, in controlling wind turbines, or particularly in medical technology where data volumes are growing at a rapid pace due to the constant increase in the resolution of imaging processes such as computed tomography.