Experimental demonstration of joint OSNR monitoring and modulation format identification using asynchronous single channel sampling

We experimentally demonstrate simultaneous optical signal-to-noise ratio (OSNR) monitoring and modulation format identification (MFI) in heterogeneous fiber-optic networks by using principal component analysis (PCA) and statistical distance measurement based pattern recognition on scatter plots obtained through asynchronous single channel sampling (ASCS). The proposed technique enables OSNR monitoring for several commonly-used modulation formats with mean OSNR estimation error of 1 dB and without requiring any information about the signal type during the online monitoring process. In addition, it successfully demonstrates the identification of unknown modulation formats of the received signals with an overall accuracy of 98.46%. The effects of chromatic dispersion (CD) on the performance of proposed technique are also analyzed. Due to the use of a single low-speed asynchronous sampling device in the proposed technique, the implementation complexity and cost of the monitoring devices can be significantly reduced.