Method to improve the performance of the optical modulation format identification system based on asynchronous amplitude histogram

•The chromatic dispersion tolerance can be expanded up to desired values by our method.•PM and NPM signals can be distinguished simply from the peak position of the AAH.•Only cheap SDCMs are used to improve the MFI system.

A method to improve the performance of the asynchronous amplitude histogram (AAH) based optical modulation format identification system is proposed. It is demonstrated that with additional static dispersion compensation modules (SDCMs), polarization and non-polarization multiplexed (PM/NPM) signals can be distinguished simply from the AAH peak position difference, while the stringent chromatic dispersion limit imposed on the MFI method can be expanded up to desired values by selectively enabling the SDCMs to minimize the width to area ratio (WAR) of the AAH. Numerical simulations and experiments are carried out to demonstrate the effectiveness of this method.