Reduction of EDFA optical power transients using power shaping

Abstract

Many erbium doped fiber amplifier (EDFA) based multi-wavelength optical networks employ techniques such as burst-switching or packet switching where the time interval between traffic blocks can be long enough to induce EDFA optical power transients. The optical power transients are created by abrupt changes in the average input power to the EDFAs and can adversely affect the performance of the network. To mitigate the effects of EDFA optical power transients on optical networks, a method called power shaping where heads and tails are joined to the beginning and end of a traffic block is investigated. A head (tail) gradually increases (decreases) the channel power by employing a bit sequence in which the probability of a "1" ("0") increases from 0 to 0.5. Theoretical and experimental results both show that EDFA optical power transients can be significantly reduced with adequate shaping periods. Experiments also show the bit error rate of the system is reduced for increased shaping periods. Power shaping is an economical means of suppressing EDFA optical power transients compared to other physical layer approaches that require the addition of specialized components and can be applied to EDFAs as well as other solid-state and Raman optical amplifiers.