Thermal Analysis And Improved Design For Fiber Laser Based On FEM

Fiber laser has been widely used for its features including excellent beam quality,high efficiency and so on.Heat is a significant restriction for fiber laser to achieve higher power and has a significant impact on the quality,efficiency and reliability.So the analysis for fiber laser is of great importance.This paper has built preliminary models for the pumping source,optical module and power module of fiber laser by reasonable simplification based on finite element method(FEM).Then the simulation models were modified and boundary conditions,parameters were determined by the physical experiments.A good agreement between simulation results and experimental data was obtained.The variation trends were similar and the maximum error was less than 10%,which proved the correction and feasibility of the simulation models.On the basis,thermo-structure deformation coupled analysis for the pumping source was carried out.The temperature field distribution,temperature characteristics,structure deformation and thermal stress distribution which were caused by heat were studied.And the thermal characteristics and performance of optical module and power module were also stimulated.The temperature variation of important components,characteristics of whole temperature distribution,the relationship between the highest temperature and environmental temperature were analyzed in detail.The theoretical time for the pumping source and optical module to recover to the initial temperature under two working modes without cooling measures was calculated.It has laid the foundation for the improved design and optimization to heat dissipation structure.The research on heat dissipation structure of the pumping source showed the relationship between chips' highest temperature and the size of submount and copper heat sink.It is the increase on width of submount and decreases on the thickness of submount that can improve the heat dissipation the most.While the changes on the length of submount and the size of copper heat sink can hardly affect the chips' temperature.By the reasonable improved design of the size of submount and copper heat sink,the chip's highest temperature has been decreased by more than 3?.Hydro-cooling measure is the decisive factor to the power supply module cooling.The thermal crosstalk of the components is also a serious problem.Two kinds of improved design schemes were put forward,which were 4 kinds of schemes for improving hydro-cooling channel structure,and 4 schemes for optimizing powercomponents distribution.The optimal scheme of the two schemes both showed a good effect that the highest temperature has been decreased by about 4? and the overall temperature distribution was improved.