| The research work of this thesis consists of two topics. The first topic focus on the investigation of the nano-semiconductor materials doped amplification fiber and the fabrication of nano InP firm doped inner cladding fiber with MCVD. The development of amplification fiber and the analysis of fabricated fiber are discussed. At present in optical communication system, the signal travels a long distance depending on fiber transmission. As a long length, high data rate and high capacity optic fiber transmission system in the main communication network, the system has to amplify or rebuild the fading optical signal at relay, which become a great demand for the development of practical optical amplifiers and network. The proposed optical amplifier, which eventually involved extensive research efforts to attempt improving its performance by the development of EDFA, resolved the relay problem. The amplification fiber becomes the key component of optical amplifiers, which is getting more attention in this research field. The dopant source of amplification fiber has been improved from rare earth to nano materials. It can be predicted that nano-semiconductor materials will become to the significant point in the doped fiber. The second topic is about a localization achievement in a sensor system by UWB signal. Because of the wireless spectrum resource becomes rarer, UWB signal application get a vast attention with the increase of short range, high capacity wireless communication consumer. Many UWB’s attractive property, such as low spectrum density, high immunity of multipath interference, high data rate, simple transceiver structure, low cost and low power consumption, make itself more important in short range wireless communication as an ideal application technology. The research works in the thesis are summarized as follows:(?) Propose a novel inner cladding fiber with InP nano thin films structure; by the characteristic analysis of fiber semiconductor dopant, the reason of choosing InP to fabricate fiber has been summarized. Propose and fabricate50m nano-semiconductor InP doped fiber with the manufacture of nano-materials and the process of fiber drawing.(?) By using plasma emission spectrometer and scanning electron microscopy, test the doping concentration and observe themicro-structure of the novel fiber. Get the optic amplification and supercontinuum generation figures. Nonlinear effects are more obvious when the pump light and tested fiber get longer.(?) With the analysis of nano-semiconductor’s optic electric property, electron and caity of InP forms localization exciton, when the electron absorbs the energy of the photon and transits. The effects of excitons and ions are observed by point charge coulomb field ocused by ions to excitons. Thus, the calculation of excitons intrinsic energy is the same as the calculation of hydrogen atom.Based on the hydrogen atomic model firstly, calculate the relative particle sizeof InP, ZnO and InSb when the quantum size effectget involved. The comparative size of the InP particle has been calculated as a result of aB=8.313nm. Calculate the particle energy band affect with the quantum size effect, the dielectric confinement effect, and Rydberg energy. The change of the energy band of particles with different sizes and light absorption wavelength has been calculated by the quantum size effect. The light absorption wavelength/changes from1220to1700nm; the band gap energy range of InP nano-particles is from0.73to1.02eV, compared to the block InP, for the InP nano-particles in sizes of5-50nm. This wavelength range is the low loss window of optic transmission in fiber communication. This point is valuable in fiber application. From the system testing, the nano InP doped fiber have gain at906-1044nm,1080-1491nm,1524-1596nm.(?) Summarize the development of short range wireless communication; discuss the theory, technology, application and standard of UWB; analyze the property of UWB based on the basic function of it; conclude the choice reason of UWB in this system mentioned below.(?) Consider the approach of location in a sensor system; use UWB impulse signal as the transmission radio between sensors; design the transceiver structure which is available for the different environment and the compatibility of existed receiver. The proposed UWB method, in which there is a coherent receiver and an FSR-UWB receiver in one system of this thesis, satisfies the requirement of different network, receiving device, complexity, and energy consumption.(?) Realize the signal transmission with UWB impulse radio; accomplish the transceiver structure with CR-UWB, which modulate the signal with orthogonal Barker Codes; analyze the characteristic of the system; get the BER curves of the CR system over multipath fading and AWGN channels; analyze the advantage of the code autocorrelation, which benefit the time synchronization of the sensor system. |
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