| The developing of information society raises an urgent request for high-speed, huge-capacity communication network. Wavelength Division Multiplexing (WDM) has been widely recognized as the main and most important technology to achieve huge-capacity optical communication network. Optical passive devices are the basis of optical networking. Because of their good and rich spectral characteristics, light weight and low cost, holographic Fresnel lenses (HFLs) and related new optical passive devices are believed to have wide applications in WDM network.In this dissertation, based on the theoretical analysis of HFLs, we investigate the basic characteristics and applications in WDM network of some new devices, especially for optical multiplexer/demultiplexer and external coupler.The main contents and innovations of this dissertation are as follows:It is pointed out that HFLs are special gratings. We show and illuminate that the scalar diffraction theory is an approximation method to calculate the diffraction efficiency of grating, and there are restrictions on its application. The coupled-wave theory is introduced for our research objects.It is proposed, for the first time, that the demultiplexing in WDM can be realized by the dispersion characteristic of holographic lens. To prove the feasibility and validity of holographic WDM, we introduce briefly the Fresnel zone plates, the predecessor of this kind of optical passive devices, and summarize the fabrication, imaging and dispersion of off-axis holographic lens.Holographic WDM is superior to other generic devices since it has both functions of focusing and defocusing. Excellence and innovation of holographic WDM are presented in the issue, and the operating principle of the demultiplexer is illustrated by diagrammatic sketch.Inherent issues in holographic WDM are investigated and discussed. Firstly, it is indicated how to depress the noise during operation process. Then on the basis of detailed analysis of grating resolution ability, we deduced the relation between resolution and grating parameters. We also showed theoretically that there is a lower limit of the irritation area to meet the system requirement in resolution. We show that zooming out hologram is not effective to cancel aberration by going through the process of reconstructing electron hologram with visible light. In the end, we point out one can minimize the wavefront aberration due to wavelength shift by optimizing configuration parameters of the optical holographic wavelength demultiplexer by the aberration redeeming method.In order to demonstrate the relations among frequency, diffraction efficiency and dispersion ability of holographic WDM, and to design a demultiplexer with a pre-selected frequency channel, four recording optical configurations are analyzed in detail, and their related devices are compared and assayed in this dissertation. Optimal recording configuration is selected, with the aid of the imaging principle of holographic lens and practical application condition of WDM.Three key criteria are provided for measuring the capability of demultiplexer. FSR and theoretical linear dispersion of holographic WDM are studied detailedly. Based on the optimized recording configuration, four demultiplexers with different recording parameters are manufactured accordingto practical conditions. The testing in visible region shows their ability to separate two laser beams with different wavelengths on the focus plane, and the separating distances are consistent with the values from theoretical analysis. Then we optimize WDM by analyzing the experimental results of further testing in infrared region. In the end, we list the channel spacing, insertion loss and crosstalk of three channels with 25nm spacing, and conclude that the WDM is the best way to take care of aberration and our device is close to practical requirement.According to the previous discussion, we found that micro holographic lenses can be used as the external couplers to couple the light emitted from a LD to a fiber,...
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