Study On Spectral Characteristics Of CdSe/ZnS-Quantum-Dot Doped Fibers With High Doping Concentrations

With the rapid development of the fiber-optic communications, moreand more demand is put forward for the wider bandwidth and flat gaincharacteristics of fiber amplifiers. The development of the highperformance fiber becomes extremely important, because it is a substratematerials of fiber amplifiers. Semiconductor nano-crystals, i. e., quantumdots are artificial materials. In recent years, people pay greatly attention toits due to their quantum size effect, their changeable radiation andabsorption peak wavelength and the full width at halfmaximum(FWHM).Semiconductor quantum dot be regarded as a gain oramplification medium applied to silica fiber structure ,these Quantum-dotdopedfiber amplifiers (QDFAs) have great promote of the fiber-opticcommunications.This paper mainly studies the changes of photoluminescence (PL)spectra peak intensities in CdSe/ZnS quantum dot fiber with high dopingconcentration. We focus on the topics in this dissertation as follows.(1) The radiation and absorption spectra of CdSe/ZnS quantum dot were measured, in order to compare with the spectrum characteristics ofCdSe/ZnS quantum dot doped fiber.(2) The range of doping concentration was estimated and opticalfibers doped with highly concentrated ((0.10~10)mg/mL) CdSe/ZnSquantum dot (QD) are prepared, and their PL spectra measured in variousdoping concentration and the fiber length.(3) The range of the exciting intensity at 473 nm with the fiber lengthwere measured and analyzed, and extinction coefficient of CdSe/ZnSquantum dot were determined.(4) A red shift of the PL-peak wavelength with the range of dopingconcentration and the fiber length were observed. we discuss on the causesof red shift and the influence of Surface defect states luminescence onquantum dot.These research results provide a powerful support for thedevelopment of possible quantum-dot-doped fiber amplifiers in the future.KEY WORDS: quantum dot doped fiber; photoluminescence spectra;doping concentration; CdSe/ZnS quantum dot; quantum-dot-doped fiberamplifiers...