Practical design of double-clad ytterbium-doped fiber amplifiers using Giles parameters

Theoretical Study of the Thermal Distribution in Yb-Doped Double-Clad Fiber Laser by Considering Different Heat Sources

“…In the present paper it is assumed that there is no Bragg reflector at the pump wavelength. In other words R 3 = 0 [32,73]. The other parameter values, such as cross-sections, first and second clad radii, steady-state lifetime, background losses, and input pump power, are given in Table 3.…”

“…By considering a value for the reflectivity of the output coupler at the pump wavelength (R 3 ), this symmetry will disappear [44]. The variation of the normalized ground and upper state of dopant densities N 1 /N , and N 2 /N with σ a p = 6.64 × 10 −25 m 2 Pump emission cross-section [74] σ e p = 4 × 10 −26 m 2 Input pump power, FWP, BDP P p = 500, 250 mW Input pump power, BWP, BDP P p = 500, 250 mW Pump background loss [33] α P = 3 dB/km power filling factor 0.0025 If there are no reflectors at the ends of the fiber, similar to the fiber amplifiers, the maximum value of the normalized density of each level must be unity [32]. So the reflectivity of the mirrors at the signal and pump wavelengths determine the shape of the graph.…”

“…where θ(r),ψ i (r, θ) are the dopant and power distributions at each wavelength respectively, and R co is the dopant distribution radius which is often equal to the core radius [31,32].…”