Noise-Figure Assessment of an All-Optical-Switching Structure Based on an SOA-MZI Coupled with an Auxiliary SOA

We propose and analyze an all-optical-switching structure based on an SOA-MZI coupled with an auxiliary SOA. This configuration improves the extinction ratio up to 16 dB over that of a single SOA-MZI. To evaluate the cascadability of such switching structures, we develop mathematical equations of the Noise Figure (NF) and show that an SOA-MZI can be considered as a standard optical amplifier from NF point of view. We also demonstrate that the NF can be written as a simple function of the parameters of SOAs composing the structure. An experimental validation of these equations is included for both structures: single SOA-MZI and coupled SOA-MZI.