Analysis of CSRZ and CSNRZ Coding for DQPSK and OQPSK Transmitter Configurations for Optical Microwave Generation Signals Based on Stimulated Brillouin Scattering

Abstract

The use of Carrier Suppressed Non-Return to Zero (CSNRZ) and Carrier Suppressed Return to Zero (CSRZ) modulation formats in Dense Wavelength Division Multiplexing (DWDM) channels at 1 Gb/s and 10 Gb/s is investigated. The results of simulated analysis using Differential Quadrature Phase Shift Keying (DQPSK) and Offset Quadrature Phase Shift Keying (OQPSK) formats are presented. We demonstrate that Stimulated Brillouin Scatteriring (SBS) is a major contribution of the back-scattering signal. At bit rate of 1 Gb/s and 10 Gb/s, CSRZ-OQPSK modulation format has a low threshold for SBS signal generation. For a data rate of 1 Gb/s, high SBS threshold of 19.76 dBm for CSRZ-DQPSK is recorded. The results can be used to suppress SBS in high power lasers which could be useful in high bit rate signal transmission