Paper Title
Analysis of DQPSK-RZ and NRZ Technique in 16*10 Gbps Long Haul WDM Systems

Abstract
Multilevel modulation format, DQPSK is considered to be an efficient technique in today’s communication system due to its high spectral efficiency. This paper presents the design architecture for 16-channel long haul WDM systems, where each channel operates at data rate of 10 Gbps. The proposed design has been simulated for 50 GHz channel spacing to compare the performance of DQPSK-RZ and -NRZ techniques. The different performance parameters have been obtained like eye diagram, optical spectrum, BER, Q factor, etc. The simulation studies show that the DQPSK NRZ performs better than that of DQPSK RZ because of fewer complications as of nonlinearities and dispersion in DQPSK NRZ. Also, DQPSK NRZ has lower BER and high Q factor value as compared to RZ. Keywords - Differential Quadrature Phase Shift Keying (DQPSK), Low Power, CSLA, Binary to Excess one Converter, Multiplexer.