| Summary: | 博士 === 元智大學 === 電機工程學系 === 99 === In this dissertation some study results on the network technologies are proposed for optical communications. We start from the component level in which a novel optical power splitter is shown using photonic crystal structure built on Si/SiO2/Si substrate where three types of air holes are utilized to construct the photonic crystal. This splitter has advantages of low insertion loss, small size (about 34?m2), easy design, and low cost features, and has potential in applications of fiber network cross connection. Next we study the optical vortex phenomenon for the photonic crystal on the SOI structure. The simulation is conducted by launching the light to the photonic crytal using FDTD method. As the diffraction caused by the certain photonic crystal arrangement introduces some optical phase singularities, the vortex phenomena can be observed. The optical vortices may be useful for the development of future optical nonlinear switches with the aid of the strong field at the vortex spot which acts as a switching point in integrated optical circuits. For the optical network architecture, we propose a new dynamic encoder/decoder for fiber CDMA networks. The theoretical models are developed using the Z-transform and E-field response of the dynamic encoder/decoder with an E/O coupler. From simulation studies, we can get some (k, f) parameter combinations to acheieve the optimum performance of the system. The new structure is simple and flexible in producing any other code sequences that are applied for the fiber network. And then, we compare performances for two types of switching configurations through the simulation studies. The Dilated Benes is found to be better than the other one. This information is useful for the optical switching network designs. Finally we analyze the SDH backbone fiber network in Taiwan with non-self-healing ring, and propose a recovery strategy when any communication link fails. This protection scheme can be applied at the beginning of the deployment for the Taiwan SDH fiber network.
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