Modeling Er/Yb fiber lasers at high powers

Abstract

Conventional models of Er/Yb co-doped fibers assume all ytterbium ions are equally involved in the energy transfer with erbium ions, governed by a singular transfer rate. This would predict output power clamping once ytterbium parasitic lasing starts, contrary to the observations that the output continued to grow albeit at a slower rate. One study explained this using elevated temperature at high powers. Our study, however, shows that elevated temperature and mode-dependent effects only play insignificant roles. A new model is developed based on the existence of isolated ytterbium ions, which can explain all the observed experimental behaviors.

Temperature Dependence of Absorption and Energy Transfer Efficiency of Er3+/Yb3+/P5+ Co-Doped Silica Fiber Core Glasses

“…A short fluorescence lifetime, τ 1 (8.14 µs), and a long fluorescence lifetime, τ 2 (~1.3 ms), were obtained. This is attributed to the existence of two types of Yb 3+ ions in the EYPS: those closely coupled to the Er 3+ ions and those uncoupled from the Er 3+ ions [11,33]. The distance between the Yb 3+ and Er 3+ ions determines whether the two can be coupled [24], and a detailed discussion is presented in Section 3.3.…”

Yb-ASE Suppression in Single-Frequency Hybrid Double Cladding Erbium–Ytterbium Co-Doped Fiber Amplifier with SMS Structure

“…According to the literature [20], the wavelength interval ∆λ can be calculated by Equation ( 2): Based on the BPM analysis of the SMS structure, the output properties of the hybrid fiber amplifier were further simulated. Besides the mentioned pump absorption and core diameter, the steady state rate equations of EYDF and other parameters are referred to the literature [28,29]. The model of the simulation is plotted in Figure 1.…”

“…The model of the simulation is plotted in Figure 1. The propagation equations for the signal power P + s(z), pump power P + p(z) , Yb-ASE power P ± YbASE (z,λ) and Er-ASE power P ± ErASE(z,λ) are shown as follows [29]: Here, m and n are the order number of the linear polarization modes LP 0m and LP 0n , respectively. The wavelength interval decreases with the MM fiber length.…”

“…The model of the simulation is plotted in Figure 1. The propagation equations for the signal power P + s (z), pump power P + p (z), Yb-ASE power P ± YbASE (z,λ) and Er-ASE power P ± ErASE (z,λ) are shown as follows [29]:…”

“…Here the symbol "±" represents forward (+) and backward (-) transmitted lights. The rate equations of the ytterbium and erbium energy system are referred to in the literature [29]. All the parameters in segment 1 are the same to those in segment 3.…”