Power efficiency vs. spectral efficiency and transmission distance in 2.5–10–40 Gbps backbone optical networks

This paper aims to revealing the interrelation between channel spacing, transmission distance, and power efficiency on WDM system level of backbone optical network which configuration in based on the concept of Mixed-Line Rate (MLR). In such MLR network, three different types of wavelengths could co-propagate over the same optical fiber: 2.5 Gbps Non-Return-to-Zero (NRZ) On-Off Keying (OOK), 10 Gbps NRZ-OOK, and 40 Gbps NRZ-Differential Phase-Shift Keying (DPSK). It is found that depending on spectral efficiency power costs per transmitted bps can be reduced more than eight times for the same transmission distance.