NONLINEARITY OF PHOTODETECTOR USING LASER FACILITY

摘要

We presented a nonlinearity measurement facility of the photodetector using laser beam in this paper, with both the power mode and the irradiance mode. Lasers with different wavelengths are used to investigate nonlinearity upon wavelength. For the power mode, the laser spot size is much smaller than the sensitive area of the photodetector. The nonlinear factor is measured with the laser power varying over six orders of magnitude. For the irradiance mode, the laser is guided into an integrating sphere to make the spot size much bigger than sensitive area of the detector. The linearity of the photodetector is measured over three orders of magnitude. Combing both modes, the nonlinearity of the silicon photodetector can be measured in a much larger dynamic range. At 632.8 nm, the nonlinear factor is found to be less than 0.015%. At other wavelengths, the nonlinear factor is found to less than 0.03%.