A THEORETICAL INVESTIGATION OF DYNAMIC ALL-OPTICAL AUTOMATIC GAIN-CONTROL IN MULTICHANNEL EDFAS AND EDFA CASCADES

We present a detailed theoretical analysis of the gain dynamics of erb ium-doped fiber amplifiers (EDFA's) that have been gain-clamped using a ring laser structure and of gain-stabilized EDFA chains, We examine and analyze the effects of attenuator level in the optical feedback pa th, switching speed, number of channels dropped or added and the choic e of lasing wavelength on the stabilization of the individual EDFA, In particular, we look at the transient power excursions and relaxation oscillations experienced by surviving channels when the number of chan nels passing through an EDFA changes, Using this analysis as a guide, we present and compare two different approaches to chain stabilization , We highlight the robustness of each approach, show some of their lim itations and advantages, and comment on the impact on multiwavelength communication systems.