Thermal analysis of end pumped fiber lasers subjected to jacket fluid cooling

End pumped lasers are highly efficient lasers particularly in diode lasers using micro lenses. The common cooling method for end-pumped systems is using water jacket or copper tube surrounding the laser rod. In this paper, the temperature distribution within a water jacket and a fiber laser end pumped by a top hat beam is studied analytically. The temperature distribution is obtained by considering the radial heat convection with fully developed laminar flow neglecting the axial heat conduction. The effect of laser dimensions and the Brinkman number on the temperature distribution are presented. The results indicate that the temperature distribution is strongly dependent on the Brinkman number. The results are presented in dimensionless form so that they can be applied to any end-pumped laser rod and fluid types. The main output of this work is that it is better for cooling purposes to have low Br values.