Characteristic research and linearity measurement of photodetectors

Abstract

To accurately measure the linearity of photodetectors in near-infrared waveband, based on the beam superposition method, a new design idea which use the tow-beam path and correlation methods was proposed. Using the 1053nm laser, and the Si photodetector as the experimental subject, a linearity measurement system of highly accurate photodetectors was designed. This system has over seven orders of magnitude dynamic range. The joint uncertainty is superior to 0.08%. Meanwhile, the linear factor of four different conditions which include the different size of incident beam spots, incident angles, positions and the environment temperature have been measured and analyzed. The experiment shows that the linearity of Si photodetector is ideal when the size of beam spots are bigger, the incident angles are smaller and the environment temperature is lower, moreover, the linearity of margin area is unsatisfactory.