High-brightness long 940-nm diode lasers with double-waveguide structure

摘要

Two double-waveguide 940 nm asymmetric structures with 8 nm In_xGa_(1-x)As quantum well (x = 0.13) are presented. They consist of an active region waveguide that includes a QW and an optical trap waveguide on the n side of the active region. The second structure has a supplementary optical wall in the p - clad that further pushes the optical field from the active region and reduces the confinement factor. The nominal lengths were chosen as 2.8 mm and 4 mm and the design values for the d/gamma ratio were 0.8 μm and 1.14 μm, respectively. Devices were fabricated with 100 μm apertures and yielded threshold current densities of 0.2 kA/cm~2 and 0.17 kA/cm~2 with corresponding slope efficiencies of 0.76 W/A and 0.85 W/A. At high current levels devices presented a power saturation behavior. The highest power values were 9.7 W (rollover) and 11.5 W (CMOD), respectively.