Power scalability of single-frequency single-mode Yb-doped fiber amplifiers is significant for their applications. Considering their potential applications in radiation environments, the influence of radiation-induced attenuation (RIA) on the power scalability of signal-frequency single-mode Yb-doped fiber amplifiers is studied in this work.
By giving the powers limited by pump brightness, stimulated Brillion scattering (SBS) and transverse mode instability (TMI), the theoretical model predicting the power limit of single-frequency single-mode Yb-doped fiber amplifiers is presented with the consideration of RIA. It is revealed that RIA cannot only lower the power limit seriously, but can also make the achievement of power limit more difficult. The analytic formula of power limit is deduced. It is found that the effect of RIA on the power limit is mainly determined by the optimum length with no RIA. It is suggested that the reduction of power limit caused by RIA can be weakened by shortening the optimum length of Yb-doped fiber.
The requirement on Yb-doped fiber for achieving certain target power is also discussed and the needed ranges of core diameter and fiber length are given analytically. It is found that the RIA will enhance the difficulty for achieving the target power by limiting the option of Yb-doped fibers. In spite of that, it is also found that such effect of RIA can be weakened by increasing the core absorption coefficient and pump brightness.
Moreover, the numerical model and pertinent formula can also reveal the effect of radiation dose by fitting the relationship of RIA and radiation dose with the empirical expressions such as Power-law. They can provide significant guidance on the designing and applications of single-frequency single-mode Yb-doped fiber amplifiers in radiation environments.