Analysis of InGaAs p-i-n photodiode frequency response

The frequency response of a InGaAs p-i-n diode was analyzed to better characterize the high-speed performances required for high-bit-rate optical communication systems. The carrier concentration and the photocurrent density in the intrinsic region were obtained analytically. The derived equations led to the frequency response which takes into account both the influence of the electric field on the carrier velocities and their nonuniform generation. In addition, the impulse response was computed by inverse Fourier transform techniques. Comparing the results with those obtained by assuming the carrier velocities independently of the electric field, discrepancies were found in the electrical power bandwidth up to 25%, and in the FWHM up to 45%.>