基于高非线性光子晶体光纤超连续谱的研究

发布时间：2018-07-03 20:51

本文选题：超连续谱 + 三零色散波长　；参考：《南京邮电大学》2015年硕士论文

【摘要】：超连续谱是指超短脉冲在非线性介质中传输时,由于色散及非线性效应的共同作用导致的脉冲光谱被展宽的现象。超连续谱因其连续光谱范围宽、稳定性好、相干性能优良等特点,在众多领域有着广泛地应用。光子晶体光纤是产生超连续谱的一种非常有效的介质,其结构设计的灵活性以及特殊的导光机制,使得它相对于传统光纤而言有着不可比拟的优势。本文主要对2μm波段飞秒脉冲激光器泵浦高非线性光子晶体光纤产生的中红外超连续谱的特性进行了模拟。文中选择了在中红外波段透过率较高的碲化物玻璃作为光子晶体光纤的基底材料,设计了具有不同色散参量的高非线性光子晶体光纤。利用分步傅里叶算法数值求解非线性薛定谔方程,模拟了中心波长为2μm的飞秒脉冲在光子晶体光纤中传输产生超连续谱的过程,分析了光纤的长度及色散参量、脉冲的峰值功率及初始宽度对超连续谱的影响。结果表明:当光纤长度为15cm,脉冲峰值功率为20KW,脉冲宽度为100fs时,得到的超连续谱的范围为1330nm~3450nm。本文中还提出了利用倍频效应得到双波长泵浦三零色散光子晶体光纤,产生可见光、近红外和中红外波段超连续谱。设计了具有三个零色散波长的光子晶体光纤结构,同样采用分步傅里叶算法模拟了超连续谱的产生过程,分析了不同光纤长度和脉冲峰值功率对产生的超连续谱的影响。结果表明:当泵浦激光脉冲中心波长为2μm、脉宽为100fs、重复频率为200KHz,传输距离为10cm、入射到PCF中的脉冲峰值功率为10KW时,得到了谱宽为690~3150nm的超连续谱,光谱具有较好的连续性和平坦度。
[Abstract]:Supercontinuum spectrum is the phenomenon that the pulse spectrum is widened due to the interaction of dispersion and nonlinear effect when ultrashort pulse propagates in nonlinear medium. The supercontinuum spectrum has been widely used in many fields because of its wide range, good stability and good coherence. Photonic crystal fiber (PCF) is a very effective medium for producing supercontinuum spectrum. Because of its flexibility in structure design and special light-guiding mechanism, PCF has an incomparable advantage over traditional optical fiber. In this paper, the characteristics of the mid-infrared supercontinuum produced by a 2 渭 m femtosecond pulse laser pumped by a high nonlinear photonic crystal fiber are simulated. The Telluride glass with high transmittance in the mid-infrared band is selected as the substrate of the photonic crystal fiber. The high nonlinear photonic crystal fiber with different dispersion parameters is designed. The nonlinear Schrodinger equation is solved numerically by using the fractional Fourier algorithm. The propagation of femtosecond pulses with a central wavelength of 2 渭 m in photonic crystal fiber (PCF) is simulated. The length and dispersion parameters of the fiber are analyzed. The influence of peak power and initial width of pulse on supercontinuum spectrum. The results show that when the fiber length is 15cm, the pulse peak power is 20kW, and the pulse width is 100fs, the range of the supercontinuum spectrum is 1330nm ~ 3450 nm. In this paper, the double wavelength pumped three zero dispersive photonic crystal fiber is obtained by using the frequency doubling effect, which produces the visible light, near infrared and mid infrared band supercontinuum spectra. The structure of photonic crystal fiber with three zero dispersion wavelengths is designed. The generation process of supercontinuum spectrum is simulated by using split step Fourier algorithm, and the influence of different fiber length and pulse peak power on the generation of supercontinuum spectrum is analyzed. The results show that when the central wavelength of the pump laser pulse is 2 渭 m, the pulse width is 100fs, the repetition rate is 200kHz, the transmission distance is 10cm, and the peak power of the pulse incident into the pump laser pulse is 10kW, the supercontinuum spectrum with the spectral width of 690~3150nm is obtained. The spectrum has good continuity and flatness.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253

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