System whereby electrical signals are converted into light signals, relayed inside optical fibres (glass or plastic fibres) and then converted back into electrical signals (Figure L 19).
Optical fibre technology is becoming more prominent, since it is completely impervious to electrical and electromagnetic interference. As a result, modern bus lines are increasingly being based on optical fibre technology. Optical fibres and power cables can be laid side by side.
In general, information is split between three optical fibres. One possible benefit of this, for example, would be the option of simultaneously transmitting control pulses in one direction and measured values in the other direction.
Figure L 19: Optical fibre technology