High power VCSEL (Vertical-Cavity Surface Emitting Lasers) has applications such as free-space optical communications and laser range finding.Two different aperture diameters 980nm,bottom-emitting VCSELs were used.The peak current trace and corresponding peak optical trace are also tested and analyzed.The relationship between the electrical pulse width and optical pulse width are discussed.Peak output power has been arrived more than 20W at 980nm wavelength while pulse width is 60ns and pulse repetition frequency is 1kHz.