Design and analysis of full duplex RoF system with efficient phase noise cancellation from a coherent RoF system

Abstract

A energy efficient and high throughput bi directional radio over fiber (RoF) system is designed and analysed. In order to preserve the phase and the magnitude of the transmitted signals, coherent detection (CD) is employed and hence an optical local oscillator (OLO) source is used. A full duplex system is designed by utilising the same OLO. The phase noise in CD system is logically cancelled using digital signal processing techniques. 10 Gb/s 16-QAM at 5.5 GHz, 10 Gb/s 2-QAM at 2.5 GHz , 5 Gb/s QPSK at 5.5 Ghz and 10 Gb/s 4-QAM at 7.5 GHz are transmitted simultaneously over 25 km optical fiber(OF). It is analysed that any coherent RoF system can be designed to a full duplex system with acceptable log(BER) and error vector magnitude(EVM) values. The minimum values of log(BER) values obtained for 16-QAM, QPSK, 2-QAM and 4-QAM are −10, −8, −16 and −22, respectively.