Investigation of SPM and XPM in soanolm and its application in wavelength conversion

Abstract

This thesis focuses on investigation of self phase modulation (SPM) and cross phase modulation (XPM) in semiconductor optical amplifier nonlinear optical loop mirror (SOA-NOLM) and its application in wavelength conversion. An improved architecture for realization the nonlinear effect using SOA is presented. The objective of this research is divided into two major parts: first, the investigation of SPM and XPM in SOA based NOLM and second, its application in wavelength conversion. In this setup, the control pump wavelength is 1540 nm and the signal wavelength is 1555 nm. The simulation setup is based on Sagnac interferometer. The gain level is obtained by setting the injection current of the SOA to 0.2 A. Three different signal repetition rates are used in the simulation; 2.5 Gbs-1, 5 Gbs-1 and 10 Gbs-1. At low input power, it is noticed that the signal encountered very small phase change, irrespective of the gain setting of the SOA. However, as the power increased the phase curve began to diverge. This implied that in order to achieve a large phase shift at low input signal power, the gain level at the SOA must be set to a higher value. In this research, the results obtained are the optimum operation parameters such as the variable injection current for the SPM and XPM effects in OptSim environment. This system can be used for future research in other photonic devices and also application in optical signal processing, optical switching and wavelength conversion. The research also gives knowledge enhancement and techniques to develop other photonic devices.