Equalization Advantages of OFFH-CDMA over WDM in EDFAs: Background Theory, State of the Art, and Simulation Results

This study stems from the observation that the gain of an EDFA (erbium doped fiber amplifier) is in general wavelength-dependent, leading to different amplification levels among WDM (wavelength division multiplexing) channels. The use of OFFH-CDMA (optical fast frequency hopped code division multiple access) offers a natural diversity of wavelength, thus eliminating the requirement of an equalization stage to achieve flat gain on all channels. In this work, computer simulations are developed to analyze equalization performance of these two transmission approaches (CDM and WDM) in EDFAs, especially when the EDFA operating point is subject to change (i.e., variable input traffic). The simulations are based on extensive modeling of WDM and OFFH-CDMA network architectures and signals, self-similar traffic, and EDFAs. The required background is presented in three strong tutorial chapters. This study should be useful to anyone working in the area of optical communications, particularly to students and research professionals. The conclusions may be greatly relevant to the development of future packet-over-light access and metropolitan networks over the next decades.