810 W continuous-wave and single-transverse-mode fibre laser using 20 [micro sign]m core Yb-doped double-clad fibre

Modeling and optimization of high-power Nd/sup 3+/-Yb/sup 3+/ codoped fiber lasers

“…The approximate solutions become less accurate when pumping at λ p = 976 nm, particularly in the limit of high pump power. APPENDIX QUASI-ANALYTICAL SOLUTION OF (2), (3), (8), AND (9) The mathematical description of the optical power spectrum propagating in the laser cavity can be significantly simplified by assuming that the oscillating laser power is strong enough to neglect the influence of the ASE on the population inversion of Nd 3+ and Yb 3+ ions. That is, we assume…”

“…The integration of the rate-propagation equations is carried iteratively along the forward and backward propagation direction, until all the ASE power densities converge to a steady-state value [10]. On each integration step, the populations of homogeneous and clustered ions are found analytically by reducing (2) and (3) emission band with the Nd 3+ absorption band, the calculated backward energy transfer from Yb 3+ to Nd 3+ is considerably weaker than the forward energy transfer, and can safely be neglected. Therefore, we assume R 60 0.…”

“…We further limit ourselves to high laser power circulating the cavity, such that the constituent ion gain is saturated, i.e., we assume N 4 (z) N Nd and N 6 (z) N Yb . Employing these assumptions to (2) and (3), one obtains for the differential signal gain …”

A simple error control strategy using MATLAB BVP solvers for Yb3+-doped fiber lasers

“…In recent years, Yb 3+ -doped fiber lasers have been attracting increasing attention [1][2][3][4][5]. Yb 3+ -doped fibers have a variety of superior properties which include an excellent energy-band structure having no excited absorption, a small quantum defect between pump and signal wavelengths, large absorption and emission cross-sections, good solubility and no quenching even in high concentration [6].…”

“…A 100 W-class linearly polarized single-mode Yb 3+ -doped fiber laser at 1120 nm with an optical efficiency of 50% has been reported [1]. Only 20 m core Yb 3+ -doped double-clad fiber, 810 W with 70% slope efficiency and 3 W lasing threshold in a single-transverse-mode output, has been experimentally realized [2]. A highly efficient cladding-pumped Yb 3+ -doped fiber laser, generating 1.36 kW of continuous-wave output power at 1.1 m with 83% slope efficiency and near diffraction-limited beam quality, has been demonstrated [3].…”