Measuring the Frequency Response of Photodiode Using Phase-Modulated Interferometric Detection

A novel method is proposed for measuring the frequency response of photodiodes. This method calculates the frequency response of the photodiode based on the gain peaks of the phase-modulated interferometric detection using a microwave network analyzer, and the half-wave voltage of the phase modulator, which is calibrated by measuring the intensity ratio of the modulated optical side-bands with the optical spectrum analyzer. The experimental results show a good match between the frequency response of photodiode measured by phase-modulated interferometric detection and by Mach-Zehnder intensity-modulated direct demodulation, as well as the data provided by the photodiode manufacturer. It provides an easy way to quickly sweep the frequency response of the photodiode, and the bias-control is not needed when calibrating half-voltage of the phase modulator.