Abstract: A short wavelength of 780 nm semiconductor laser has been designed and fabricated, and the mode locking by external cavity feedback has been studied. The epitaxial layers were prepared by the metal organic chemical vapor deposition technology. GaAsP and GaInP were used as the quantum well and waveguide layer, respectively. The confinement layers were AlGaInP material with low refractive index. Using the ultra-high vacuum cleavage and passivation technology, an amorphous ZnSe passivation layer was deposited on the laser cavity facets. For the original device the catastrophic optical damage (COD) occurred when the output power was 2.5 W. The ZnSe passivated device did not show COD phenomenon until 10.1 W. When the current was 10 A, the output power was 10.1 W, and the electro-optical conversion efficiency was 54%. Before and after the wavelength being locked by the volume Bragg grating (VBG), the full width at half maximum of the spectrum were 2.6 nm and 0.06 nm, respectively, and the wavelength range was about 230 pm through controlling the temperature of VBG.