Methods for Measuring the RF Half-wave Voltage of LiNbO3 Optical Modulators

We present methods to measure the RF half-wave voltage V-pi(f) using a photodetector and an RF spectrum analyzer based oil (i) the nonlinear response and (it) the two-point technique. The results obtained from these methods for an LiNbO3 Mach-Zehnder optical modulator at 6.3 GHz are compared and good agreement is found between all the methods. Also, measurement methods based on optical-spectrum techniques, namely, the optical response and two-tone methods, are analyzed. An error analysis shows that the new and simpler techniques proposed offer similar levels of measurement uncertainty. (c) 2005 Wiley Periodicals, Inc.