Energy – Spectral Efficiency Enhancement in Dual-Polarization Quadratic Phase Shift Keying in Optical Networks

Abstract

Advanced modulation formats are used in modern fiber optic communication systems to enhance spectral efficiency (SE), increase data rate, and improve noise. An important example of this modulation is Dual-Polarization Quadrature Phase Shift Keying (DP-QPSK) which a data rate of 40 Gbps and a transmission distance of 100.2 km is considered, and the performance of the system is investigated. Two mathematical model are proposed one to model the tradeoff between Energy Efficiency (EE) and SE and the other for EE versus Continuous Wave transmitter Power (PCW). The simulations are validated by using MATLAB software. The outcomes of the simulations were carried out using Optisystem software 22. Bit Error Rate (BER), Quality Factor (Q-factor) and constellation diagrams are evaluated for different PCW ranging from -10 to 10 dB and it is observed that with increase in PCW, BER decreases and Q increases. To illustrate this improvement, a 100.2km fiber optic link with conventional QPSK modulation is taken as current study. Revealing limitations in system performance. For the optimal performance optimization prosses, the Particle Swarm Optimization (PSO) algorithm is used by MATLAB software to optimize and find optimum PCW over extended ranges. The DP-QPSK system achieves the best quality factor of 72.1284 at 8.9655dB input power, but EE degrades beyond a certain power due to non-linear effects. In this paper, optimal power control strategies are identified which can be directly incorporated into the design and management of high-speed optical networks to enhance their performance and guarantee their long-term efficiency.