Theoretical And Experimental Research Of All-Optical OFDM Chip Based On Discrete Fourier Transform

With emergence of high bandwidth service and popularity of optical access network, the resulting rapid increase of network traffic brings higher requirements of capacity of the optical communication network. For this reason, increasing the spectrum efficiency and the information carried on each unit of frequency is the best way to meet the needs of high capacity requirements under the limited frequency resource. To further enhance the capacity and dispersion tolerance of optical communication system, the researchers proposed the all-optical orthogonal frequency division multiplexing (OOFDM) technology. In this thesis, the concept of all-optical discrete OFDM technology has been proposed and demonstrated in principle. Then the thesis completes the designing and manufacturing of the OFDM chip, as well as the experiment system.Firstly, the dissertation describes the OFDM technology in principle and demonstrates the orthogonality of the technology utilizing the mathematical model. Discretizing the continuous OFDM symbol based on Nyquist sampling theorem, the thesis gets the conclusion that inverse discrete Furrier transform (IDFT) and discrete Furrier transform (DFT) can achieve discrete OFDM multiplexing and demultiplexing respectively.Then, the all-optical OFDM transmission system with two inputs was stimulated through VPI Transmission Maker V7.6. The thesis gets the conclusion that the OOFDM system has a better transmission performance than the amplitude shift keying (ASK) system, but suffering higher power penalty.Then, the designing and manufacturing of a two-point all-optical inverse discrete Furrier transform (OIDFT) chip will be described in details. And the dissertation describes the packaging of all-optical OFDM chip and designing of OFDM modulation and demodulation apparatus.Finally, the phase shifting function of the waveguide is demonstrated through two experiments, as well as two important problems are found in the chip designing. And then the thesis proposes the corresponding solutions, and indicates the direction of the whole project.