Research On Noise Suppression Technology Of RoF Link Based On Phase Modulation

Microwave photonics combines the advantages of microwave communication and optical fiber transmission technology,such as long transmission distance,anti-interference and low loss,and develops a variety of technologies based on microwave photonics.ROF(radio over fiber)link system is an important branch of microwave photonics,which plays an important role in the application of microwave photonics.Compared with the traditional communication,ROF link communication system has the characteristics of small loss,wide bandwidth and strong stability.It plays an important role in shipboard communication,airborne communication,satellite communication and military communication confrontation.There are many factors that affect the signal quality of Ro F link system,and noise is one of the key factors.Relative intensity noise(RIN),phase noise and other noises will affect the system signal quality.Reducing the output noise of the system can effectively improve the distortion of the output signal.Noise power and signal-to-noise ratio are important parameters to judge the output signal quality of Ro F link system.How to reduce the noise power and improve the signal-to-noise ratio(SNR)is an important research topic in ROF link system.The specific work of this paper is as follows:1.The core devices of Ro F link system and several noise definitions and measurement methods are introduced.Two kinds of all-optical structure noise suppression systems,semiconductor optical amplifier method and balance detection method,are proposed.2.Combining the advantages of the two kinds of noise suppression systems,a comprehensive noise suppression system is proposed.In this system,a semiconductor optical amplifier(SOA)is introduced to realize the noise suppression of Ro F link system by using gain saturation property,and a coherent balance detection technology is introduced to improve the output signal-to-noise ratio of Ro F link system by using balance detection.3.The simulation of the integrated noise suppression system with optisystem shows that the output SNR of Ro F link system can be effectively improved by the integrated noise suppression system under the optimal operating parameters.The research results show that: the comprehensive noise suppression system has good noise suppression effect under the best working conditions,and as an all-optical structure,it will not introduce external electrical signals,the working effect is stable,the structure is simple,and has a good development prospect.