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Investigation And Fabrication Of Large-core-diameter Fibers And Multi-core Fibers Based On High-speed Large-capacity Optical Fiber Communications

Posted on:2015-05-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:S W ZhengFull Text:PDF
GTID:1228330431984612Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
ABSTRACT:Novel large-mode-area multi-core and single-core optical fibers are important parts of ultra-high-speed large-capacity long-distance optical fiber communication system, the transmission rate of which is100Gbit/s,1.6Tbit/s or even100Tbit/s. In order to build the practical applications of high-speed large-capacity all-optical communication network, the necessary condition of realizing high-power large-capacity transmission is increasing the mode field area of the fiber, decreasing the nonlinear effect and enlarging the transmission capacity of optical fiber.Supported by National973Program, National Nature Science Foundation Program and Fundamental Research Funds for the Central Universities, the design and fabrication of large-core-diameter optical fibers and multi-core fibers for high-speed large-capacity long-distance optical fiber communication have been investigated theoretically and experimentally. The main innovative achievements are listed as follows:1. Considering the couplings of all the cores--adjacent cores and non-adjacent cores, a detailed analytical solution for the coupled-mode theory for homogeneous7-core optical fibers are present, and the normalized analytical solutions for the mode amplitudes are obtained. For the long-distance transmission, considering all the power coupling coefficients of adjacent cores and non-adjacent cores, a detailed analytical solution for the coupled-power theory for homogeneous7-core optical fibers are present. Besides the center core excitation, the definition of crosstalk for outer-core excitation is present for the first time. With the consideration of all the excitation conditions, we perfect the definition of crosstalk. The crosstalk properties in multi-core fibers are investigated experimentally. We show that the crosstalk in multi-core fiber can be explained well by employing the coupled-power theory.2. The effects of different trench parameters on the coupling coefficient Cmn, crosstalk XT and the effective area Aeff of fundamental mode in the trench-assisted multi-core fiber are investigated systematically. Based on the trench optimization, we provide a guideline for the fiber design of low crosstalk and/or large mode area. It is shown that the Aeff of each core can be increased to140-150μm2, and the cross-talk can be decreased to-76dB by adjusting the trench parameters. The large-mode-area low-crosstalk trench-assisted multi-core fiber could be a potential candidate for practical applications. In addition, applying the trench-assisted structure to single-core fiber, the large-mode-area trench-assisted single-core fiber could be realized.3. A novel dual-air-hole and/or four-air-hole multi-core dual-mode large-mode-area optical fiber is proposed. The definition of strictly dual-mode operation is proposed for the first time. The proposed fiber can decrease the number of second-order modes by half while realizing large mode area of fundamental mode by adjusting the structural parameters. A strictly dual-mode operation can be achieved in the fiber (HE11and HE21). The single-mode operation can be also realized by adjusting the structural parameters. The maximum effective area Aeff of fundamental modes is approximately4025μm. And the bending loss is much less than that in commonly step-index large-mode-area fiber.4. A novel multilayer-core intrinsically single-mode large-mode-area low-bending-loss fiber is proposed. The multilayer structure in the core could achieve a very low equivalent core-cladding refractive index difference on the order of10-4or even10-5. The single-mode large mode area of100-12000μm2could be achieved. Furthermore, the bending property could be improved by1-2orders of magnitude in this multilayer-core structure compared with the SIF with the same effective area when the outermost layer is depressed-index ring. The fabricated multilayer-core fiber achieved a large effective area (more than236μm2) with ultra low bending loss (0.0146dB/turn at R=0.02m).
Keywords/Search Tags:multi-core fiber, coupled-mode theory, coupled-power theory, crosstalk, dual-mode operation, bending loss
PDF Full Text Request
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