飞秒泵浦不同锥长微结构光纤超连续谱的产生

发布时间：2018-03-15 06:13

本文选题：微结构光纤　切入点：超连续谱　出处：《光谱学与光谱分析》2016年07期 　论文类型：期刊论文

【摘要】：对飞秒脉冲泵浦下,不同锥长及锥腰直径的微结构光纤的超连续谱产生进行了实验研究。采用"快速低温拉锥方法",在保持d/A不变的情况下,对实验室自制的空气孔间距以=6.53μm,归一化孔径d/A=0.79的微结构光纤进行了拉锥,分别得到6,8,10 mm等不同锥长微结构光纤。理论计算表明,随着锥长变长,锥腰直径变小,锥腰处零色散波长向短波移动:未拉锥及6,8和10 mm锥微结构光纤锥腰处零色散波长分别为1 129,885,806和637 nm。利用中心波长为810 nm,重复频率76 MHz,脉宽120 fs的钛蓝宝石飞秒激光器对拉锥后微结构光纤进行了实验研究:锥长为6 mm时,泵浦光中心波长位于整根光纤的正常色散区,锥腰的零色散点附近,内脉冲拉曼散射和级联四波混频是光谱初始展宽的主要因素。泵浦功率达到450 mW时,在可见波段390~461 nm及红外波段1 134~1 512 nm形成—5 dB的平坦宽带连续光谱。泵浦功率达到500 mW时,出现366~2 450 nm覆盖紫外、可见、近红外、中红外的超连续谱,其光谱红蓝移边缘已经接近实验用微结构光纤的传输带宽。锥长为8mm、泵浦功率为450 mW时,在群速度匹配和群加速度失配的共同影响下,连续谱蓝移边缘达到366 nm,比6 mm锥时蓝移9 nm;锥长为10 mm时,由于锥腰处零色散点移动到可见光区域,可见区光谱仍能满足相位匹配条件。通过级联四波混频效应,在可见区域实现了频率上转换及光谱蓝移。泵浦光功率达到500 mW时,在382~412 nm得到谱宽仅为30 nm,转换效率达到27.7%的频率上转换。
[Abstract]:The generation of supercontinuum spectra of microstructured optical fibers with different cone lengths and tapered waist diameters under femtosecond pulse pumping is studied experimentally. The "rapid low-temperature taping method" is used to keep the D / A constant. The micro-structure fiber with air hole spacing of 6.53 渭 m and normalized aperture d / A _ (0.79) was taped, and the microstructural fibers with different conical lengths, such as 6 ~ 810 mm, were obtained. The theoretical calculation shows that the diameter of the tapered waist becomes smaller with the increasing of the cone length, and the diameter of the tapered waist becomes smaller with the increase of the cone length. The zero dispersion wavelength at the tapered waist moves to short wave: the zero dispersion wavelength at the tapered waist is 1 129,885,806 and 637 nm respectively. The center wavelength is 810 nm, the repetition rate is 76 MHz, and the pulse width is 120 fs. The wavelength of zero dispersion at the tapered waist is 1 129,885,806 and 637 nm, respectively. The femtosecond of titanium sapphire with a pulse width of 120fs is obtained by using the center wavelength of 810 nm. The experimental study of microstructured fiber after tapered laser is carried out: when the cone length is 6 mm, The central wavelength of the pump is located in the normal dispersion region of the whole fiber, and the zero dispersion point of the cone waist is near. The internal pulse Raman scattering and cascaded four-wave mixing are the main factors for the initial broadening of the spectrum. When the pump power reaches 450 MW, In the visible band (390 ~ 461 nm) and the infrared band (1 134 ~ 1 512 nm), a flat broadband continuous spectrum of -5 dB is formed. When the pump power is up to 500 MW, there are 366N ~ (2 450) nm covering ultraviolet spectrum, visible, near infrared, and mid-infrared supercontinuum spectra. The spectral red-blue shift edge is close to the transmission bandwidth of the experimental microstructured fiber. When the cone length is 8 mm and the pump power is 450 MW, under the influence of group velocity matching and group acceleration mismatch, The blue shift edge of the continuous spectrum reaches 366 nm, which is 9 nm than that of the 6 mm cone. When the cone length is 10 mm, the visible spectrum can still satisfy the phase matching condition because the zero dispersion point at the waist of the cone moves to the visible region. The frequency up-conversion and spectral blue shift are realized in the visible region. When the pump power reaches 500MW, the spectrum width is only 30 nm and the conversion efficiency is 27.7% nm at 382 412nm.
【作者单位】：燕山大学信息科学与工程学院;南京信息工程大学江苏省气象探测与信息处理重点实验室;河北省特种光纤与光纤传感重点实验室;
【基金】：国家自然科学基金项目(61205084,61405173,61275093,61307110,61405172) 河北省自然科学基金项目(F2014203194) 江苏省气象探测与信息处理重点实验室开放课题(KDXS1107,KDXS1108)资助
【分类号】：TN253

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