基于色散调制的硒化砷条型波导的超连续谱产生  

Supercontinuum Spectral Generation in Dispersive Modulated As2Se3 Striped Waveguide

作　　者：宋茂壮 杨振 张政 王荣平 SONG Maozhuang;YANG Zhen;ZHANG Zheng;WANG Rongping(Laboratory of Infrared Material and Devices,Advanced Technology Research Institute,Ningbo University,Ningbo 315211,China)

机构地区：[1]宁波大学高等技术研究院红外材料与器件实验室,宁波315211

出　　处：《光子学报》2024年第3期133-143,共11页Acta Photonica Sinica

基　　金：国家重点研发计划(No.2020YFB1805900);浙江省宁波市3315创新团队项目,武汉光电国家研究中心开放基金项目(No.2022WNLOKF001)。

摘　　要：研究了基于色散调制硒化砷条型波导超连续谱的产生,通过调整波导结构参数,使零色散点转移到通信波长附近,在1.55μm波长处获得反常色散。波导长度为10 mm,波导横截面面积为500 nm×800nm,获得1.55μm波长处的非线性系数为48.754W^(-1)·m^(-1)。利用脉宽为579fs、重复频率为50 MHz、峰值功率为70 W的光纤激光脉冲在波导中产生了带宽600 nm的超连续谱。研究结果提供了一种使用常见激光泵浦平面波导实现集成片上超连续光源的途径。Supercontinuum generation requires suitable material platform with a high third-order optical nonlinearity and a broad transmission window.In terms of these,chalcogenide glass has advantages such as a wide transmission range,high linear and nonlinear refractive index,and low two-photon absorption,making it promising for near-to mid-infrared nonlinear optical applications.However,the fabrication process of chalcogenide glass optical waveguides still needs to be optimized,and how to excite the supercontinuum using the pumping sources that are cheaper and commercially available is still a challenging issue.Therefore,there is an urgent need to develop chalcogenide-based on-chip light sources that are pumped by 1.55μm laser.In this paper,we used commercial software(COMSOL Multiphysics)based on complete vector finite components to simulate the dispersion properties of the strip As2Se3 waveguide using SiO2 as a bottom cladding and air as a top cladding layer,the zero dispersion wavelength can be shifted to 1.55μm in the waveguide with a width of 800 nm and height of 500 nm,where the effective refractive index of both TEo and TMo modes are kept at more than 2,indicating that both of the modes can be well confined in the waveguide.We also calculated the wavelength dependence of the area of the effective modes and nonlinear coefficients,and found that,the form one increases while the latter one decreases with increasing wavelength.Then,we explored the fabrication process of chalcogenide waveguide based on As2Se3.We employed thermal evaporation to prepare As_(2)Se_(3) thin films on thermally oxidized silicon wafer with a 3μm thick SiO2 layer,and then vacuum annealed the films at 150℃ in the vacuum in order to reduce the defects of the films and decrease the optical loss of the film.The As2Se3 stripe waveguide was patterned by the electron beam lithography(RAITH e-LINE Plus).Optical microscopy and scanning electron microscopy observation showed that the waveguide has a smooth side and wall profiles.We further used the c

关 键 词：超连续谱 条型波导 色散调控 硒化砷 反常色散 

分 类 号：TN252[电子电信—物理电子学]