Optical Generation Of High Frequency Microwave

As a fresh and rising technology, microwave photonics, which is the product of microwave and photonics, has a big potential of application. ROF (radio over fiber) system, for instance, combines the low loss of optical communication and the removability of microwave communication into one system. In addition, THz wave, which is difficult to be generated in electronic field, becomes possible by optical ways. This technology promotes the study on THz wave and the development of imaging technology with THz. Moreover, high frequency microwave, whose frequency is too high to be dealt with in electronics field, can be treated with optical methods by uploading them to the optical field. All of these applications are based on optical generation of high frequency microwave.Optical generation of high frequency microwave is studied in this paper. First, microwave photonics is introduced, and several applications are also enumerated. Second, common technologies used in optical generation of microwave are summarized. Third, based on the optical generation of microwave with mode locked laser, microwave, whose frequency is dependent on the free spectrum range of the mode locked laser, is generated by the modes beating. Talbot effect is induced by the optical dispersion. The frequency of microwave can be improved because of Talbot effect which can improve the repeat rate of the output of mode locked laser. Because the repeat rate is as high as several GHz, the nonlinearity and high order dispersion are also studied in the system. The simulation figures and experimental figures are presented in the paper. Last, drawbacks of the fiber dispersion are pointed out, such as high cost, high loss, difficult to be integrated. In order to resolve the drawbacks, a novel system in which LCFG (linear chirped fiber grating) replaces the fiber in the original system is studied. Simulation figures are presented in this paper.