The Research Of Single Sideband Suppression For ROF Communication System

ROF(Radio-Over-Fiber) technology uses optical carrier signal transmit and distribute high frequency radio signals, combines the advantages of mobile communication technology and fiber-optic communication system, point-to-multi-points access technology provided by ultra wideband wireless communication network and high bandwidth, highly reliable connection provided by optical networks, with broad coverage and easy maintain, It will play a very important role in future wideband wireless communications.In the radio-over-fiber (ROF) system, the fiber chromatic dispersion will cause severe RF power penalty in the traditional double-sideband (DSB) modulation scheme. Because of fiber chromatic dispersion, the two sideband of DSB signal will beat frequency with center carrier absolutely, it will generate two millimeter-wave signals, they have the same frequency but have unequal phase, they will interfere with each other and superimposed the final millimeter-wave signal, it will cause microwave and millimeter wave signal periodically with the optical fiber transmission distance attenuation, the signal transmission performance of ROF system will become bad, limiting the distance of transmission of the signals in optical fibers. In order to overcome the power penalty, some optical single-sideband (SSB) modulation techniques have been introduced. This article will mainly study the single-sideband suppressed technology that generated millimeter wave, mainly focus on the fiber grating used in single-sideband suppressed and its performance,The primary achievements in this paper areas follows:1. First of all, the paper summarize the several major millimeter-wave generation scheme for ROF system, derived fiber grating coupling theory, given the simplified coupled equations analytical solutions. Use coupling theory and transfer matrix method simulation analyzes the commonly used types of Fiber Gratings.2. The paper completes theoretical derivation and simulation the reason of the power decrement of generated microwave and millimeter wave that cased by fiber chromatic dispersion in DSB modulation scheme. The results show that the two sideband of DSB signal will beat frequency with center carrier absolutely, it will generate two millimeter-wave signals, they have the same frequency but have unequal phase, they will interfere with each other and superimposed the final millimeter-wave signal, and deduce the relationship between the final millimeter wave signal and the fiber transmission distance、chromatic dispersion coefficient and other parameters.3. A new DSB modulation scheme based on double electrode LiNB modulator with inhibition of odd sideband was proposed, study the performance of CFBG、TFBG、 LPG used to achieve single sideband suppression technology based on the new DSB modulation scheme, We detailed analysis and simulation experiments on double sideband signal filtering process and filtering results, get the relationship between the final millimeter wave signal and the fiber transmission distance、chromatic dispersion coefficient and other parameters. The results show that the above three kinds of single sideband suppression scheme are not only possible to reduce the carrier sideband suppression ratio(CSR) of the single sideband modulation signal, but also improve the sensitivity of the receiving of the system, but also to effectively inhibit the benefits of fiber dispersion causes the microwave and millimeter wave signal periodically attenuate, to avoid the fiber dispersion effect on the performance of the transmission signal. In the above study on the basis of the results, a ROF full duplex communication system based the three kinds of single sideband suppression technology, simulation analysis the transmission performance of the above three single sideband suppressed program in the full duplex communication system of ROF...