Asymmetric broad-waveguide separate-confinement heterostructure (BW-SCH) quantum well (QW) laser diode emitting at 808 nm is analyzed and designed theoretically. The dependence of the optical field distribution, vertical far-field angle, and internal loss on different thicknesses of the upper waveguide layer is calculated and analyzed. Calculated results show that when the thicknesses of the lower and upper waveguide layers are 0.45 and 0.3 \mu m, respectively, for the devices with 100-\mu m-wide stripe and 1000-\mu m-long cavity, an output power of 7.6 W at 8 A, a vertical far-field angle of 37°, a slope efficiency of 1.32 W/A, and a threshold current of 189 mA can be obtained.