We measure the half-wave voltage of LiNbO<sub>3</sub> phase modulators in a 26-GHz wideband frequency range, and then analyze it by the phase modulation photonic peak gain linked to the interferometric demodulation. The optical interferometer is constructed with two 50:50 couplers and two fiber arms with a 1-m difference in fiber length. The photonic link gain peaks are frequency dependent, as indicated by the differential time delay in the interferometer. The procedure described is a new and practical half-wave voltage measurement method that can accurately predict the nonlinear frequency characteristics of the phase modulator. Moreover, the method can be applied to various types of LiNbO<sub>3</sub> phase modulators.
© 2013 Chinese Optics LettersPDF Article