Performance Degradation of 100 Gb/s PM-QPSK and 400 Gb/s PM- 16QAM Single Carrier and Dual Carrier Coherent Systems Due to Cascaded Optical Filters

ABSTRACT In this paper, we studied the performance degradation of single-carrier and dual-carrier 100 Gb/s and 400 Gb/s systems due to optical filter cascade with 50 and 100/150 GHz channel spacing, respectively. Eye closure penalty (ECP) is used as a performance evaluation metric, where we use two types of filters: fiber Bragg grating (FBG) and thin-film filters (TFF). Simulation results indicate that dual-carrier systems are more severely affected by the optical filter cascade when compared to single-carrier systems using same type of filters and t h e same channel spacing. This performance degradation is due to the misalignment of the two carriers with respect to the filters’ center frequency, and to the presence of crosstalk between the two carriers.