“Auto-Tune” for Fibre Optic Technology

The way that Data currently operates is fraught with problems, relating to capacity and noise imperfections. However, this week an EU-funded team has demonstrated a prototype device that can "clean up" a noisy data signal and re-transmit it with fuller capacity.

Data is sent as a sequence of bits coded into the properties of a light beam piped down an optical fibre, so understandably these bits can become distorted over great lengths of fibre.


Two different kinds of phase noise can be the cause of this making the data unintelligible; the first being imperfections in reproducing exactly when different parts of the light signal arrive. The second because of "cross-talk", signals sent down a fibre that influence one another. Existing electronics can overcome this but the result is a reduced data capacity.


There is also a foreseeable problem due to the growth in bandwidth-hungry applications such as YouTube and iPlayer that will eventually stretch the limits of long-distance fibre links.


The prototype device demonstrated by the team makes use of advances both in optical fibre technology and in lasers, which are used to "lock on" to the signal and distinguish it from noise.


The output signal is returned to its sharp-edged nature at the precise digital levels that are needed; it is, in one sense, like a fibre-optic version of the auto-tune software that "cleans up" singers' voices.


It was stressed that the device was a laboratory demonstration, and some way from industrial application - but that similar technology would become essential in a world where bandwidth needs are always on the rise.