Study On Applications Of Optical Time-domain Fractional Fourier Transform On Optical Communications

Fourier transform has been wildly applied in all fields of science. However, as the development of research scale grows wider, the limitation of Fourier transform has been revealed in handling some problems, which is reflected in the fact that it is a kind of global transform and could only get the whole spectrum of signals but not the part time-frequency information. And for the non-stationary signals, the part time-frequency information usually is more important, so in order to analyze and handle this kind of signals, fractional Fourier transform (FRFT) is proposed. So far, fractional Fourier transform has been applied in many fields including differential equation, quantum mechanics, diffraction theory, optical transmission, optical systems, optical information processing and optical image processing, and so on.The thesis will first introduce the definition of fraction Fourier transform and its many properties, and then simply introduce some typical application of FRFT in different fields. The definition is divided into three steps and the detailed realization of FRFT is also given. Base on the time-space duality theory, the implementation of FRFT is given in space, which employs two lenses and with a space distance in the middle. Besides, with the similar method, the realization of FRFT is proposed in time-domain way.Based on the implementation of FRFT, a new optical pulse transmission scheme is proposed and different effects of several factors on the performance of pulse propagation in the fibers, which are the pre-chirp coefficient, the order number of FRFT, the pulse width, the pulse peak power and so on, are discussed. Finally the thesis gives detailed analysis on these factors and summarizes the simulation results and prospect the future research of FRFT in optical communication systems.