Observation and Modeling of Filtering Penalties in Optical Switched Networks

Flex-grid WSS filters in ROADMs can degrade signal quality of transmission (QoT) due to single-sided (SS) and dual-sided (DS) passband narrowing from frequency deviations or multi-carrier transceivers. Moreover, filtering QoT penalty depends on the relative placement of ASE and filters and on the implementation-dependent capabilities of the DSP receiver. We first validate an already published model based on time-consuming experimental calibration on commercial devices including SS filter response. We then present and validate using numerical simulations a faster analytical approach based on the MMSE theory suitable for modern networks digital twins and planners.