Numerical investigation of the thermal effect on Yb-cavity-copumped Er/Yb codoped fiber amplifiers.

Thermal effects are critical constraints for developing high-power Er/Yb-codoped fiber amplifiers (EYDFAs), especially those with an auxiliary Yb-band cavity. In this paper, we developed a numerical model to investigate the temperature-dependent effects on EYDFAs with an Yb-band cavity with consideration of thermal-induced cross-section changes. Our results show that the quantum-defect-induced heat affects the performance of the EYDFA, and its effect varies with the resonant wavelength of the Yb-band cavity. There is a finite applicable resonant wavelength range limited by thermal damage. So, it is important to take into account the thermal effect during the design of such EYDFAs in order to optimize their performance and determine the heat dissipation systems.