10kW矩形光斑激光空间合束器光学透镜的有限元热分析  

Finite Element Thermal Analysis of Optical Lenses in 10 kW Rectangular Spot Laser Space Combiner

作　　者：李奔 周井锋 王艺 白杨[1,2] LI Ben;ZHOU Jingfeng;WANG Yi;BAI Yang(Institute of Photonics&Photon-Technology,Northwest University,Xi'an 710127,China;State Key Laboratory of Photon-Technology in Western China Energy,Xi'an 710127,China)

机构地区：[1]西北大学光子学与光子技术研究所,西安710127 [2]省部共建西部能源光子技术国家重点实验室,西安710127

出　　处：《光子学报》2022年第2期125-136,共12页Acta Photonica Sinica

基　　金：陕西省教育厅服务地方专项计划(No.19JC040);陕西省省重点研发计划(No.2020GY-118);国家重点研发计划(No.2017YFB0405102)。

摘　　要：为实现快速、柔性矩形光斑激光表面热处理,提出了一种基于空间非相干合束的10 kW矩形光斑激光合束器。同时入射该合束器的18束光纤传输的972 nm半导体激光束按照“交错式矩形”同轴排列。在构建18束激光总体热源数学模型基础上,对10 kW激光合束1000 s时间内合束器中所有光学透镜的温度分布、热变形分布和热应力分布规律进行了有限元分析研究,结合实验测量验证了合束器长期工作的安全性和可靠性。连续运转1000 s时,合束器输出的矩形合束激光的最大功率达到10.64 kW,功率不稳定性<±1.2%。研究结果可为超高功率激光空间合束系统的安全性和可靠性评估提供参考依据。A space-transmission high-power near-infrared semiconductor laser beam with a rectangular laser spot is one of the key tools to improve the efficiency and quality of laser surface heat treatment.However,this kind of laser is difficult to apply to the surface heat treatment of flexible lasers inside workpieces.This is because the volume of the lasers increases greatly with increasing laser power and is affected by the space transmission of the laser beam.The spot of the ultrahigh-power laser beam from a commercial high-power fiber laser or a fiber-transmitted semiconductor laser is circular,which makes it difficult to control the spot overlap rate during the laser surface heat treatment process.It is difficult to change the ultrahigh-power circular laser spot into a rectangular spot through beam shaping technology.Laser incoherent spatial combining based on multifiber transmission is an effective method to reduce the risk of high-power laser transmission in a single fiber and realize the flexible transmission of high-power lasers.It has quickly become a research hotspot in the field of ultrahigh power laser systems.To solve the spot overlap rate control problem of ultrahigh power lasers transmitted by fibers in flexible laser surface heat treatment,a design scheme of arranging 18 semiconductor laser beams at 972 nm transmitted by fibers according to a“staggered rectangle”and implementing space incoherent beam combination was proposed in this paper.Based on this,a set of 10 kW rectangular spot laser beam combiners was developed.The optical elements in the combiner are all optical lenses made of fused silica glass.It is widely known that the accumulation of heat generated by long-term ultrahigh-power laser beam irradiation will produce serious thermal effects inside the optical lens,resulting in reduced beam quality and even irreversible damage inside the optical lens,which will seriously affect the safety and reliability of the combiner for long-term operation.However,the structural shielding of the combiner of

关 键 词：激光 空间非相干合束 光学透镜 体热源 温度场 热变形 热应力 有限元分析 

分 类 号：TN248[电子电信—物理电子学]