A review for development of feedforward linearisation system on radio over fiber links

Radio over fiber technology provides the efficient and cost effective solution for increased bandwidth demand in wireless area but suffer from performance degradation due to optical transmitter nonlinearity that generates distortion of inband, harmonic and intermodulation in modulating RF signal. A feedforward linearisation is a powerful technique that prefers because can reduce the broadband distortion in microwave/millimeter wave frequencies, reduce the all orders of distortion and the laser relative intensity noise (RIN) simultaneously. This paper reviewed the research progress of feedforward linearisation system in radio over fiber application. Feedforward linearisation system was reported that can suppress third-order intermodulation distortion (IMD3) from 10-20 and RIN reduction from 1-10 dB simultaneously at operating frequency from 0-5 GHz with linearization bandwidth 500-850 MHz. The highest operating frequency is 5.2 GHz with 10 dB IMD3 reduction on 500 MHz linearization bandwidth. Therefore, feedforward linearisation system can improved the RoF performance by linearity improvement so that the system can operate at broadband frequency.