In order to obtain high power， narrow line width and near diffraction limit output semiconductor laser diodes， the high order Bragg gratings （HOBGs） and master oscillator power-amplifier （MOPA） have been fabricated in the waveguide of HOBGs-MOPA laser diodes with an emission wavelength of 980 nm. The longitudinal mode of HOBGs-MOPA was selected by the HOBGs with a period of 11.37 μm. The single-mode optical power is amplified by a tapered waveguide with an angle of 6°. In this paper， we present a single mode laser diode with continuous wave power 2.8 W at a 3 dB line-width of 31 pm. The laser diode operates in a close to diffraction-limited optical mode （M ²=2.51， laterally）.