Swept Frequency Measurement of Electrooptic Phase Modulators Using Dispersive Fibers

A novel method based on the use of dispersive fibers is proposed and experimentally demonstrated for measuring the high-frequency modulation index, as well as the half-wave voltage, of electro-optic phase modulators. Fiber dispersion causes the phase modulated signal to become intensity modulated, which allows for the high resolution swept frequency measurement of phase modulators, using a vector network analyzer. The proposed method holds without the restriction of small-signal approximation, which is applicable for the measurement at different driving levels and operating wavelengths.