Quasi-velocity-matched electrooptic phase modulator for the synthesis of ultrashort optical pulses

We report a quasi-velocity-matched electrooptic (EO) phase modulator in LiTaO/sub 3/ with periodic domain inversion. It is suitable for deep modulation at high frequency and can be used to generate ultra-wide sideband signals for forming ultrashort optical pulses. In experiments, phase modulation with a modulation index of 57 rad has been successfully obtained at 16.25 GHz, and thereby optical sidebands extending over as wide as 1.85 THz (FWHM) have been attained. The sidebands produced are broad enough to form subpicosecond pulses using the chirping-compression method.