Comparison of C-band and L-band WDM-PON systems performance with PAM-4 modulation format

This paper evaluates the impact of the optical and electrical filtering on the performance of wavelength-division-multiplexed passive optical network (WDM-PON) transmission system with four-level pulse amplitude modulation (PAM-4) format and 40 Gbit/s (20 Gbaud/s) per-channel data rate for the optical C and L frequency bands. Paper determines the combination of the implemented electrical and optical filters bandwidth, which ensures transmission with minimal bit error ratio (BER) as well as with minimal received optical signal power. Obtained results revealed that filters' bandwidth optimization has similar effect on the PAM-4 signal transmission in optical C and L bands. However, the utilization of the L-band frequencies instead of the C-band frequencies leads to the decrease of the transmission quality, reduction of the maximal provided transmission distance as well as to the increase of the minimal received optical signal power required to provide transmission with BER<;1×10^-3.