Design of High-power Ridge Waveguide 980-nm Pump Lasers

The design of ridge waveguide semiconductor pump lasers poses particular simulation problems, since an accurate modeling of the electric and thermal effects and of the optical guiding capabilities is needed. We developed a model whose self-consistent application allows the evaluation of, among others, the threshold current of the lasing mode and the gain margin of the higher order modes, the P-I characteristic, the power coupled in the fiber, and the far field pattern. Particular attention is paid to the experimental verification of the transverse single mode operation region, and its evolution at high injection levels. The appropriate conditions for operation in the 150 - 200 mW single mode output power range have been found.