Abstract: An auto feedback and photo attenuation structure of a vertical cavity surface emitting laser (VCSEL) includes a VCSEL combined with a monitor photodetector (MPD). The thickness of the absorbing layer of the MPD may be adjusted, so that when output light of different wavelengths passes through the MPD, a portion of light may be absorbed by the absorbing layer to function as a feedback path of an auto power control, and a portion of light may penetrate through the absorbing layer, and may satisfy the requirement of the eye safety class I. The thickness of the absorbing layer of the MPD may be controlled precisely, thereby increasing the quality of products and decreasing cost of fabrication.