Design and simulation of gain-flattened ultra wideband fiber amplifiers covering S-, C-, and L-bands.

摘要

A novel design of a gain-flattened amplifier that covers an ultra-wideband including the S-, C-, and L-bands is presented. The amplifier is comprised of a split-band structure, which amplifies the S-, C-, and L-band signals in separate paths then recombines the amplified signals for the final output to the transmission fiber. For C-band amplification, a two-stage erbium doped fiber amplifier (EDFA) with mid-stage gain equalization filter (GEF) topology was used, for L-band amplification, single-stage longer EDFA topology was used. While for S-band amplification, a Raman fiber amplifier (RFA) with counter-propagating multiple-pump configuration was adopted. Using the VPIcomponentMaker™ software package from VPI Systems™, the design was simulated and tested for optimization. Computer simulations analyzed the gain and noise-figure of the novel amplifier. Approximately 30-dB gain with an overall gain ripple less than 1.6 dB and low noise-figure, and gain-bandwidth over 120 nm can be achieved. It encompasses more than 144 ITU-T channels at 100 GHz spacing. Comparing with previous reported work in the literature, the amplification range of the novel fiber amplifier not only covers the C- and L-bands, but also covers the S-band, which is the first investigation of this type. And hasn't been reported in literature by others for discrete amplification. This makes the novel amplifier described here as having the widest gain-flattened amplification bandwidth range among the discrete fiber amplifiers investigated till today.