The future role of semiconductor optical amplifiers

The recent rapid development of Erbium doped fibre amplifiers with high gains, high saturation powers and low noise figures [1,2] has deflected the attention of system engineers from the older semiconductor technology [3] and it is thus now hard to find new published papers which use semiconductor amplifiers in a system context. Device development has not ceased however [4] and the performance of semiconductor amplifiers has improved considerably. In addition there are important applications for which doped fibre amplifiers are not suitable at present e.g. at 1.3 µm, and others for which they will never be suitable, e.g. as fast optical switches. This presentation attempts to review these possibilities for future practical application of semiconductor optical amplifiers in the light of the recent developments of the technology.