Explicit exact three-dimensional analytical temperature distribution in passively and actively cooled high-power fibre lasers

Abstract

Efficiency and beam quality enhancement of high-power lasers require effective thermal management. In order to determine the temperature distribution in double-cladding high-power continuous wave fibre lasers, the heat transfer equation is analytically solved. Using the exact derived temperature distributions, the ultimate pump power before thermal damage, which is one of the key subjects of consideration in high-power laser design, is achieved.

Theoretical analysis of doping management and its effects on power scaling

“…The quantities a and b are core cladding radii, respectively [30]. The steady-state heat equations for both core and cladding regions are given as follows [24,36,37]:…”

“…A 1i A 2i , B 1i , andB 2i are arbitrary constants to be determined from boundary conditions given below [30,33,36,37].…”

“…The main reason is that in short-length fiber lasers the axial temperature changes significantly as a result of the exponential changing of thermal load in the longitudinal direction [33], resulting in the emergence of an important drawback of the 2-D frame approach concerned with the plain-strain approximation of calculating thermal stress [33,34]. As 2-D flux approximation came up short in modeling of thermal load of the short length fiber lasers, the need for a comprehensive 3-D analysis of thermal effects was underlined [35][36][37].…”

Theoretical analysis of doping management

“…Heating and beam-distorting effects are critical for high-power lasers [1]. Therefore, there is a great deal of interest in scaling average power along with heat removal and thermal management [12]. With regard to research, it can be said that previous solutions were focused on improvements of pumping diodes [3][5] and pumping technologies as well as fabrication and cooling process of gain fibers at different wavelengths [8] [12].…”

“…Therefore, there is a great deal of interest in scaling average power along with heat removal and thermal management [12]. With regard to research, it can be said that previous solutions were focused on improvements of pumping diodes [3][5] and pumping technologies as well as fabrication and cooling process of gain fibers at different wavelengths [8] [12]. In this context, important step forward in the evolution of the high gain fibers was introduction of cladding pumping [17].…”