Characterization of optical Mach–Zehnder modulator using DC measurements

This Letter presents a simple but effective method for characterizing the frequency response of broadband Mach–Zehnder optical modulators. The method measures the modulator’s direct current output versus the modulating frequency to determine the frequency response and requires no calibrated broadband photodetector or measurements of the electrical or optical spectrum or radio frequency power. Therefore, it significantly simplifies characterization. The method is suitable for in-situ measurements and can be automated.