SUMMARY
With the steady increase in the heterogeneous Internet traffic, the optical wavelength division multiplexed (WDM) networks based on a mixed line rate (MLR) strategy have emerged as an efficient-solution. Also, with the migration from the legacy to the higher line rate(s), the advanced modulation format(s) (MF) is/are required. However, use of appropriate MF(s) for the higher line rate(s) still remains an open problem. In this article, we compare the performance of an On-Off Keying (OOK), Differential Phase Shift Keying (DPSK) and Duo-binary (DB) MF based MLR network in the presence of various physical layer impairment(s) (PLIs) for which, we propose a mathematical model based on various MFs. As a novelty, we validate the proposed theoretical model’s results by comparing them with the results obtained through simulations from OptSim, which has not been conducted in any existing study(s) thus far. Our simulation results show that the DB MF is perfectly suitable for high spectral-efficient MLR systems owing to its high resistance to various PLIs.