全正色散双包层拉锥Ge-As-Se-Te光纤中的宽带相干超连续谱产生  

Broadband and Coherent Supercontinuum Generation in All-Normal-Dispersion Double-Clad Ge-As-Se-Te Fiber Taper

作　　者：王莹莹 张楠 张培晴 王训四 戴世勋 Wang Yingying;Zhang Nan;Zhang Peiqing;Wang Xunsi;Dai Shixun(Laboratory of Infrared Material and Devices,The Research Institute of Advanced Technologies,Ningbo University,Ningbo,Zhejiang 315211,China;College of Electronic Science and Engineering,Nanjing University,Nanjing,Jiangsu 210093,China;Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province,Ningbo,Zhejiang 315211,China;Engineering Research Center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Provinces,Ningbo,Zhejiang 315211,China;International Science&Technology Cooperation Base of Infrared Materials and Devices of Zhejiang Provinces,Ningbo,Zhejiang 315211,China)

机构地区：[1]宁波大学高等技术研究院红外材料及器件实验室,浙江宁波315211 [2]南京大学电子科学与工程学院,江苏南京210093 [3]浙江省光电探测材料及器件重点实验室,浙江宁波315211 [4]先进红外光电材料及器件浙江省工程研究中心,浙江宁波315211 [5]红外材料及器件研究浙江国际科技合作基地,浙江宁波315211

出　　处：《中国激光》2022年第1期129-135,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(62090064,61875094);宁波大学王宽诚幸福基金。

摘　　要：制备了具有全正色散特性的Ge-As-Se-Te双包层拉锥光纤,并研究了其中的红外超连续谱输出特性。所采用的拉锥光纤的纤芯直径为12μm,外包层直径为108μm,锥区长度为9.8 mm。利用6μm的飞秒激光泵浦10 cm长的拉锥光纤,获得了1.5~14.3μm的超连续谱输出。与同样纤芯直径的单包层拉锥光纤相比,双包层结构不仅增强了光纤的机械强度,还减少了泵浦能量在锥区的损耗,进一步拓宽了超连续谱的宽度。模拟计算结果表明,该超连续谱具有高的相干性。Objective Supercontinuum(SC)sources with spatial coherence,broad bandwidth,and high brightness have received considerable attention due to their significant potential in various applications,such as sensing,biomedical science,and spectral tissue imaging.In particular,the mid-infrared(MIR)spectral region is regarded as an important topic because most molecules exhibit fundamental vibrational absorption bands in this region and leave distinctive spectral fingerprints.Chalcogenide(ChG)glass has a comparatively wide transparency window(over20μm)and high optical nonlinearity(up to a thousand times greater than that of silica glass),making them as excellent candidates for MIR SC generation.Using fiber tapers with all-normal dispersion(ANDi)is an effective method to generate a broadband SC spectrum with high coherence in ChG fibers.However,extremely small diameters of a few micron of the tapered step-index fiber result in an energy loss in the transition region and a very low mechanical strength during preparation,optical testing and practical applications.To improve the mechanical strength and enhance the nonlinearity of the fiber,double-clad fiber tapers can be considered,which can achieve an ANDi characteristic by adding one clad layer.Methods The ChG double-clad fiber(DCF)used in this work is made of Ge_(15)As_(25)Se_(40)Te_(20) core glass,Ge_(15)As_(25)Se_(45)Te_(15) inner cladding glass,and Ge_(15)As_(25)Se_(50)Te_(10) outer cladding glass.High-purity materials are purified to remove oxygen,water,and carbon by dynamical distillation,and three glass rods(core size of 9 mm×15 mm,inner cladding size of 26 mm×15 mm,and outer cladding size of 26 mm×15 mm)are prepared using the melt-quenching method.The linear refractive indices of the cladding glass and core glasses(Fig.1(a))are measured using an IR ellipsometer.The preform Ⅰ (ratio of core diameter to cladding diameter is 1:3)and preform Ⅱ (ratio of core glass diameter to inner and outer cladding diameters is 1:3:9)are obtained by isolated stacked extrusion ma

关 键 词：激光光学 非线性光学 光纤制备 超连续谱产生 光纤光学 

分 类 号：O437[机械工程—光学工程]