Ke ZHANG, Feng-ping YAN, Wen-guo HAN, et al. Theoretical Study of Pumping Method of High Power Tm3+-doped Fiber Amplifier for Thermal Effect Management. [J]. Chinese Journal of Luminescence 41(7):839-848(2020)
Ke ZHANG, Feng-ping YAN, Wen-guo HAN, et al. Theoretical Study of Pumping Method of High Power Tm3+-doped Fiber Amplifier for Thermal Effect Management. [J]. Chinese Journal of Luminescence 41(7):839-848(2020) DOI： 10.37188/fgxb20204107.0839.
Theoretical Study of Pumping Method of High Power Tm3+-doped Fiber Amplifier for Thermal Effect Management
The high-power thulium(Tm,3+,)doped fiber laser(TDFL) based on the structure of master oscillator power-amplifier is the main type of 2 μm band high-power fiber lasers. Study on thermal effect management of the thulium doped fiber amplifier(TDFA) stage means a lot to the continuously power-scaling of the TDFL. This paper mainly focuses on the theoretical research on the optimization of the pumping method of TDFA for thermal effect management. We use the Runge-Kutta method and Newton iteration method to solve the steady-state rate equation of TDFA under different pumping methods. And, on the basis of the heat conduction equation, the temperature distributions of Tm,3+, doped fiber(Thulium-doped fiber, TDF) along the radial and axial direction are simulated. Combining with the genetic algorithm theory, the segmentally pumping method is studied. Through optimizing of the relative parameters, using a 2 020 nm input signal light with a power of 5 W, a total 793 nm laser pump power of 1 000 W and a TDF with an absorption coefficient of 3.1 dB/m and a total length of 11 m which is divided into 5 segments(2.4, 2, 2, 2, 2.6 m), we obtained an amplified signal laser with an output power of 284.5 W and a slope efficiency of 28.45%, and the maximum temperature at the outer cladding boundary of the TDF is only 86.28 ℃ with a uniform temperature distribution along the whole fiber. Compared with a TDFA using traditional forward pumping or dual-end pumping mode, the thermal effect has been significantly improved.
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