1060-nm Ridge Waveguide Lasers Based on Extremely Wide Waveguides for 1.3-W Continuous-Wave Emission Into a Single Mode With FWHM Divergence Angle of $9^{\circ}\times 6^{\circ}$

Extremely large epitaxial waveguides with thickness t_WG = 8.6 μm enable diode lasers with very narrow vertical divergence angle. We demonstrate that when such designs are processed in ridge waveguide laser format, there is substantial interaction between the vertical and lateral waveguiding mechanisms. For very narrow stripes with width w ≪ t_WG, such interaction leads to lasing operation in the second-order mode in the vertical direction. For the case of an optimal stripe width w~t_WG single fundamental mode operation is achieved, with peak kink-free optical output power of 1.3 W and beam divergence angles (vertical, lateral) of 9° × 6° at full-width at half-maximum and 17° × 13° with 95% power content. The maximum brightness is 90 MW × cm^-2 sr^-1 for 95% power content.