Frequency stability of a waveguide-type frequency selection switch for optical FDM distribution systems

This work describes the frequency stability of a 128-channel waveguide-type frequency selection switch (FSSW) for optical FDM distribution systems. Special attention is given to crosstalk level degradation due to chip temperature changes. First, the allowable total crosstalk level for the FSK-direct detection scheme is discussed both theoretically and experimentally. Next, taking the crosstalk degradation into consideration, the allowable ambient temperature change is estimated. Finally, the influence of the applied power change in the switching operation is evaluated. As a result, it is estimated that the FSSW is sufficiently stable without additional feedback loops, even if the ambient temperature change is wider than ±43°C