Analysis and Reduction of Crosstalk in Hybrid TWDM System using Transmitter Line Coding Diversity

Objectives: Optical fibres are becoming the backbone of communication network due to its huge data carrying capacities. But there are many losses in the data transfer such as crosstalk which can reduce the data carrying capacity of an optical fibre network. Methods: This paper presents a crosstalk immune transmitter diversity hybrid modulation for wavelength division passive optical network, with the incorporation of Differential Phase Shift Keying (DPSK) format for downstream and Non Return-Zero (NRZ) for upstream. Findings: The network becomes less prone to nonlinearities and enables the system to support 6144/512 users. Data rate of system has been achieved for 120 Gbps downstream as each wavelength carry 10 Gbps and total 80 Gbps for upstream. An acceptable Bit Error Rate (BER) range i.e. 10-9 has been attained for a significant distance of 110 Km for both directions. The results have been attained without any dispersion compensation and costly modules only using Erbium Doped Fiber Amplifier (EDFA) for downstream. A semiconductor optical amplifier is placed to re modulate data streams. Also comparison is being done by using same transmitter and hybrid transmitters. It is observed that Differential Phase Shift Keying (DPSK) for one direction Non Return-Zero (NRZ) for upstream provide better results. Applications: This model can significantly reduce the crosstalk over an optical fibre network during the transmission of data in upstream and downstream by achieving 80Gbps and 10Gbps respectively