用于飞秒激光制备光纤光栅的相位掩模研制  

Phase mask for fabrication of fiber Bragg gratings by femtosecond laser

作　　者：刘全 黄爽爽[1] 鲁金超 陈新华 吴建宏 LIU Quan;HUANG Shuang-shuang;LU Jin-chao;CHEN Xin-hua;WU Jian-hong(School of Optoelectronic Science and Engineering&Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University,Suzhou 215006,China;Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province&Key Lab of Modern Optical Technologies of Education Ministry of China,Soochow University,Suzhou 215006,China)

机构地区：[1]苏州大学光电科学与工程学院&苏州纳米科技协同创新中心,江苏苏州215006 [2]江苏省先进光学制造技术重点实验室&教育部现代光学技术重点实验室,江苏苏州215006

出　　处：《光学精密工程》2020年第4期844-850,共7页Optics and Precision Engineering

基　　金：装备预研项目(No.41423030101);国家自然科学基金资助项目(No.60907017);上海市全固态激光器与应用技术重点实验室开放课题(No.2014ADL02);江苏高校优势学科建设工程(PAPD)资助项目。

摘　　要：利用严格耦合波理论分析了用于520 nm波长飞秒激光制备光纤光栅的相位掩模的衍射特性,当相位掩模是矩形槽形时,占宽比在0.32~0.43之间,槽形深度在0.57~0.67μm之间时,能够保证零级衍射效率抑制在2%以内,同时±1级的衍射效率大于35%。在此基础上,利用全息光刻-离子束刻蚀技术,制作了用于520 nm波长飞秒激光的周期为1067 nm、有效面积大于40 mm×30 mm的相位掩模。实际制作的相位掩模是梯形槽形,槽深是0.665μm,分析了梯形槽形中梯形角对衍射效率的影响。实验测量表明,该相位掩模的零级衍射效率小于2%,±1级衍射效率大于40%,满足飞秒激光制作光纤光栅的需要。The diffraction characteristics of a phase mask for a 520 nm wavelength Femtosecond laser-written FBG are investigated in this study using rigorous coupled-wave theory(RCWT).The results demonstrate that when the phase mask is a rectangular profile,the groove depth and the duty cycle of phase mask must be within the range of 0.57-0.67μm and 0.32-0.43,respectively,to achieve the desired 0-order diffraction efficiency of less than 2%and±1-order diffraction efficiency of more than 35%.Using a fused silica phase mask in a 520 nm wavelength femtosecond laser with a period of 1067 nm,a ruled area 40 mm×30 mm was fabricated via holographic lithography-ion beam etching.The actually produced phase mask was observed to be a trapezoidal profile with a groove depth of 0.665μm,whose influence on the diffraction efficiency was analyzed.Experimental measurements demonstrated that the 0-order diffraction efficiency was less than 2%and±1-order diffraction efficiency was more than 40%,which meet the requirement for fabrication of fiber Bragg grating by femtosecond laser.

关 键 词：全息光刻 相位掩模 严格耦合波理论 离子束刻蚀 衍射效率 

分 类 号：TN253[电子电信—物理电子学] TN305.7