【作者】 李春生；

【导师】 桑新柱； 颜玢玢；

【作者基本信息】 北京邮电大学 ， 光学工程， 2017， 硕士

【摘要】 随着物联网、云计算的迅猛发展,全球信息量正以指数式爆炸增长,人们对光纤的通信容量和带宽提出越来越高的要求。目前,商用的掺铒光纤放大器和掺铒光纤激光器工作在C+L波段,这限制了光纤的通信容量。随着光纤制作工艺的提升,石英光纤的低损耗通信波段已扩展到O、E、S、C、L、U波段,所以,面向未来高速率通信、覆盖整个通信窗口的超宽带光纤放大器和激光器急需被开发。掺铋光纤在近红外波段的辐射光谱可以覆盖1000-1500 nm和1600-1775nm波段,新型的铋铒共掺光纤甚至可以覆盖整个1000-1700 nm波段,它们不仅可以用于制作通信系统中的超宽带光纤放大器和激光器,还可以为面向物联网的智能化光纤传感网络提供理想光源。本文对铋铒共掺光纤的近红外荧光、放大特性及其作为超宽带光源在波分复用光纤光栅传感网络中的应用进行了研究。主要工作内容包括:(1)研究一种铋铒共掺光纤的近红外荧光和增益特性,系统分析了泵浦功率、泵浦波长、光纤长度和温度对荧光特性的影响。在830 nm半导体激光器泵浦情况下,研究了 1460 nm、1535 nm、1550 nm三个波段的小信号增益,与我们之前研究的光纤中铋铒掺杂浓度在同一个数量级不同,该光纤中铋的掺杂浓度比铒低一个数量级。(2)利用一种铋铒共掺光纤制作超宽带光纤光源,系统研究了光源的输出光谱和稳定性。830 nm半导体激光器泵浦情况下,该宽带光源在980-1630 nm波段实现了光谱输出,半高宽可达525 nm,输出光谱的标准差小于0.05 dB,具有很好的稳定性。(3)研究基于铋铒共掺光纤超宽带光源的波分复用光纤光栅传感网络,通过O和C波段的温度及应变传感实验,证实了该方案可大幅度提高传感网络的复用容量,可构建超大规模传感网络,对大型结构进行传感监测,且传感网络中各光纤光栅之间的串扰很小。更多还原

【Abstract】 With the rapid development of Internet of Things and cloud computing, the amount of information in the world increase exponentially. So the demand on the communication capacity and bandwidth of the optical fiber are increasingly high. At present,the commercial erbium-doped fiber amplifier and laser work in C+L band normally, which will limit the communication capacity of the optical fiber. However,with the technology improvement of optical fiber production, the low loss communication band of silica fiber has been extended to O, E, S, C, L and U bands.Therefore, it is urgent to develop ultra-broadband fiber amplifiers and fiber lasers that covering the whole communication window for future high rate communication. The near infrared radiation spectrum of bismuth doped fiber can cover 1000-1500 um and 1600-1775 nm while the novel bismuth and erbium co-doped fiber (BEDF) can even cover the entire 1000-1700 nm band. They can be used to fabricate ultra-broadband fiber amplifiers and fiber lasers that used in telecommunication systems. In addition,they can also be used to fabricate ultra broadband light source for the intelligent optical fiber sensor networks. In this paper, the near infrared fluorescence and amplification characteristics of BEDF as well as its application in wavelength division multiplexed fiber Bragg grating sensing system are studied. The main work includes:(1) Near infrared fluorescence and gain properties of the novel BEDF are investigated. The influence of the pump power, pump wavelength, fiber length and temperature on the fluorescence characteristics are analyzed systematically. The small signal gain of three bands, 1460 nm, 1535 nm and 1550 nm, are investigated under a 830 nm laser diode pumping. The bismuth doped concentration is one order of magnitude lower than that of erbium doped concentration in our work, which is different from the previous fiber we studied, in which the bismuth and erbium concentration are in the same level.(2) An ultra-broadband light source is fabricated by using BEDF, and the output spectrum and stability of light source are studied systematically. When it is pumped by 830 nm laser diode, the output light of the light source can cover 980-1630 nm and the full width at half maximum (FWHM) is up to 525 nm. The standard deviation of output spectrum is less than 0.05 dB, showing very good stability.(3) BEDF ultra-broadband light source was used in wavelength division multiplexing fiber Bragg grating (FBG) sensing system, and strain sensing at O band and C band have been achieved. Experimental results demonstrate that, the multiplexing capacity of the sensing system will be greatly improved by using BEDF based ultra-broadband light sources. Especially, the super-large scale sensor networks can be constructed to monitor large structures, and the crosstalk between the fiber gratings is very small.更多还原