Quasi-velocity-matched guided-wave optical modulator for integrated ultrashort pulse generators

Summary form only given. Ultrashort optical pulses are attractive because of their potential applications in many fields. We have even studied and demonstrated the generation of femto-second optical pulses using the electro-optic modulation method, which has many advantages compared to the conventional mode-locked laser systems; the controllability of a pulse width, a pulse shape, a pulse position, and a repetition frequency, the availability of CW laser sources of any wavelength, the stability, and the capability of the synchronization with other electric signals. One of the key devices on this method is an electro-optic phase modulator for the generation of wide optical side-bands. We have developed the quasi-velocity-matched (QVM) traveling-wave modulator of a bulk type by utilizing the technology of the domain inversion of ferroelectric materials so as to compensate the velocity mismatch between the light and the modulation signal, and demonstrated the generation of the ultrawide optical sidebands of 3 THz. We present the fabrication and the demonstration of novel QVM guided-wave modulators using LiTaO/sub 3/ for the first time as far as we know. Utilizing the guided-wave structure, the driving power for the modulation was significantly reduced. It is also possible to integrate them with other optical circuits for the pulse compression on the same substrate and to construct integrated optical pulse generators.