By optimizing the doping distribution of the waveguide structure and the P-cladding layer, the overlap between the optical field and the P-cladding layer doped area is reduced, thereby reducing the internal optical loss of the semiconductor laser. At the same time, the use of wide band gap GaAsP as the barrier layer reduces the carrier leakage in the active region and achieves an internal optical loss of 0.259 cm ^-1. The prepared single emitter device with a wavelength of 975 nm, a stripe width of 100 μm and a cavity length of 4 mm has a continuous-wave output optical power of 21 W at room temperature. When the output power is 20 W, the power conversion efficiency is still greater than 50%.