Abstract

Erbium-doped fiber amplifiers (EDFAs) have many applications due to their high gain, polarization, insensitivity, wide bandwidth, low noise, and immunity to cross-talk. All-optical EDFA switching for network testing and routing eliminates optical /electrical conversion while integrating switching with gain. Optical switching can be done from tens of kilometers because of the very low fiber loss. We show that a short (~10 ns) optical pulse within the EDFA bandwidth, but not at the signal wavelength, can rapidly reduce the gain. Amplification of the weak pulse at the beginning of the amplifier produces a strong pulse that rapidly depletes the population inversion near the amplifier output. Strong absorption in the depopulated region near the fiber output end produces gain compression with a high dynamic range. Switching time is limited only by the pulse duration and can be <1 ns. This is an extreme case of cross-talk in which the pulse depletes the stored energy orders of magnitude faster than other mechanisms.^1,2

© 1993 Optical Society of America