OCDMA over WDM system using DPSK modulation technique for gigabit passive optical network

Abstract

Optical code division multiple access (OCDMA) system has provides immense opportunity for all optical access networks regarding the flexibility, asynchronous access, high-volume transmission capacity, simple network control and increasing the security. This thesis deploys OCDMA technology to design a new hybrid (OCDMA over WDM) system and comparing the performance in different detection techniques with different data rates. To design a new OCDMA over WDM system, code selection is a concerning part for getting better system performance with high security. In this thesis, detection techniques used Modified Double Weight Code (MDW) as signature code. In OCDMA systems, generally the cross-correlation functions created that causes multiple access inference noise. Multiple Access Interference (MAI) is type of interference caused by multiple cellular users who are using the same frequency allocation at the same time. To mitigate this MAI issue, detection technique is used throughout the thesis. Advanced modulation technique is applied to increase the system performance with high bit-error-rates (≤10-10). The investigated results obtained by using direct detection, AND subtraction detection and complementary subtraction detection techniques for similar number of active users. Detection properties of short noise, thermal noise and phase-induced intensity noise are considered simultaneously for performance analysis. System simulation performance are carried out some design parameters such as bit-error-rate, distance, input power, received power, channel spacing. To compare the simulation results we have to integrate commercial optical simulator “Optisystem” version 12.