electronic dispersion compensation (EDC)

When transmitting high data rates via optical fibers, dispersion problems occur, which lead to a dragging of the light pulses. Attempts are being made to counteract this dragging by means of dispersion compensation. The E/O converters and O/E converters at the end points of the optical fibers prove to be particularly critical.

Of course, this effect can be compensated for by using dispersion-compensated optical fibers such as DCF(Dispersion Compensating Fiber) or NDSF (Non Dispersion Shifted Fiber), but in the case of existing optical fibers, other measures must be taken to reduce the pulse loops.

In general, dispersion compensation can be achieved by several adjustable delay components connected in series. The pulse signal applied to the optical fiber(FOC) is thereby accumulated in propagation time and amplitude to account for the dispersion of the E/O converter. Since it is not possible to perform manually adjustable dispersion compensation, Electronic Dispersion Compensation (EDC) is a suitable solution here, in which the filter parameters are automatically adjusted as a function of the optical transmission path. EDC circuits are implemented in the optical modules or the optical transceivers. Thus, electronic dispersion compensation in optical networks( ON) can be used to significantly increase the number of optical carriers( OC) and thus increase the transmission bandwidth of optical networks. For Gigabit Ethernet and 10-Gigabit Ethernet, EDC compensation can increase the distances for long-haul links by up to 50%.

The Optical Internetworking Forum( OIF), together with ITU-T SG15, coordinates the various optical modules, systems and components with regard to Electronic Dispersion Compensation.