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Investigations Of Bismuth Doped Silica Fiber On The Properties And Applications

Posted on:2017-02-13Degree:MasterType:Thesis
Country:ChinaCandidate:P LiuFull Text:PDF
GTID:2348330503489830Subject:Optical Engineering
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Since Dianov prepared first bismuth-doped fiber in 2005, the bismuth-doped fiber have drawn much attention for its huge proficiency.However,Greater bottleneck have blocked its development, mainly because of the near-infrared light-emitting mechanism of bismuth-doped optical fiber is not clear, complicated preparation process and other issues.To solve these problems, this paper focus on bismuth-doped optical fiber, to carry out research work from the technical preparation ? the basic parameters and test methods ?irradiation temperature characteristics?amplified spontaneous emission aspects.Firstly, on the basis of previous studies on the improvement of laboratory-doped bismuth fiber preparation technology, elaborate improved process chemical vapor deposition techniques, combined with gas phase and solution doping technique based on the preparation technique to prepare a 10 / 130?m single package bismuth-doped silica fiber layer. The basic parameters and the optical properties of the fiber were tested.We report Bi-doped fibers prepared by modified chemical vapor deposition combination with solution doping process.The fibers are divided into three groups under 60 Co radiations with different doses. The absorption spectra and fluorescence spectra of the fiber before and after irradiation are investigated. The dependence of fluorescence intensity of the fiber on temperature(-40 ? — 70 ?) are measured. Experimental results show that the radiation-induced absorptions(RIAs) of the fibers increase significantly at 700 nm and 800 nm with the increase of the irradiation dose. We ascribe the great enhancement of the RIA of the fiber to the generation of more Bi near-infrared(NIR) active centers. Because near infrared nonluminous valance state like Bi3+ captures free electrons and converts into Bi2+,and further into Bi+under the 60 Co radiations with different doses. We also find that the NIR fluorescence spectra are stable before and after irradiation under 976 nm LD excitation.The possibility of communication in a radiation environment is proved, such as in outer space is proved. In addition, the fluorescence intensity dependence on temperature in a full-temperature range is analyzed, and we find that the fluorescence intensity decreases with the increase of temperature. It is contributed to the Bi active center that Bi+ may gradually turn into nonluminous Bi metallic colloids during thermal activation. The variation law of fluorescence intensity is analyzed in the whole range of temperature. We believe that thevariation law of fluorescence intensity provides data and basis for the stable operation of bismuth-doped fiber laser in the future.The one-way back ASE configuration have been constructed. By testing and analysis of the relationship between fiber length, pump power and the output light characteristic parameters(such as the average wavelength, output bandwidth, power spectrum). The results showed that while fiber length is longer, there are two emission peaks near 1150 nm and1400nm at 808 nm pumped. By optimizing the appropriate fiber length and pumping power,the optical bandwidth can reach 460 nm and optical power spectral density uniformly distributed. In term of ultra-wide band, bismuth-doped fiber has a great potential applications on fluorescent light source.
Keywords/Search Tags:Bismuth-doped fiber, Modified Chemical Vapor Deposition(MCVD), ?radiation, Amplified Spontaneous Emission(ASE)
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