Bias-Independent Inter-Modulation Method for Simultaneously Measuring Low-Frequency Modulation and Bias Half-Wave Voltages of Mach-Zehnder Modulators

Abstract A bias-independent inter-modulation method is proposed and demonstrated for measuring low-frequency modulation bias half-wave voltages of Mach-Zehnder modulators (MZMs). The consists simultaneous sinusoidal on the ports MZM under test. Sinusoidal-modulated sidebands heterodyne with each other generate desired products after photodetection, which allows extracting both depth voltage MZM. Our independent MZM, can be canceled out by carefully choosing sinusoidal-modulation frequencies. Moreover, enables low swing MZMs. Experiments indicate that features simple setup high accuracy response measurement ranging from 1 Hz to MHz.