Gain stabilization in all-optical gain-clamped cascade of praseodymium-doped fluoride fiber amplifiers

The authors present theoretical results of an analysis of an all-optical ga in-clamped (AOGC) praseodymium-doped fluoride fiber amplifier (PDFFA) for p rotecting surviving channels in an amplified wavelength division multiplexe d (WDM) network with six cascaded PDFFAs. The theoretical analysis is based on application of a large-signal numerical model that takes into account p ropagation of pump, signal, and downstream and upstream amplified spontaneo us emission and includes rime variation effects in a four-level laser syste m. It is shown that power Excursions caused in an eight-channel WDM network by loss/addition of six channels could be lower than 1 dB and free of rela xation oscillations if the AOGC PDFFA is strongly inverted and the total lo ss of the ring resonator is appropriately set.