Comparison of EDFA Stages using Pump Power Splitting or Pump Bypass Technique with Respect to Steady-state Performance

摘要

Providing the pump power emitted by a single pump laser to several coils of erbium-doped fibers (EDFs) is a common way to reduce cost of optical amplifiers. Typically, this is achieved by using a pump power splitter or by employing the pump bypass technique. Both techniques are compared with respect to steady-state performance. In addition to the standard parameters noise figure and output power, gain variations induced by population of the third energy level are also considered.The investigations cover single EDFA stages, multistage ED'FAs using the mentioned techniques for the first stage, and two-stage gam-flattened EDFAs with variable gain. Pump power splitting offers good performance in all test cases and shows the most balanced behavior. Simulation results for a two stage EDFA with embedded variable attenuator reveal that the pump power splitting approach provides better noise performance for a given maximum pump power if the splitting ratio and the length of the coils are set at an optimum.