UC San Diego

We report a simple method to obtain a p-i-n photodiode’s harmonic distortion levels at different frequencies from the microwave reflection coefficient S11 of the photodiode under dc illumination. This approach is based upon the tracking of the photodiode’s microwave impedance with S11 at different incident optical powers before severe saturation occurs at low bias or at high optical power. The second-harmonic distortions measured from a waveguide photodiode agree closely with those predicted from the S11 data.