TERAHERTZ OPTICAL FREQUENCY COMB GENERATION AND PHASE-LOCKING OF AN OPTICAL PARAMETRIC OSCILLATOR AT 665 GHZ

We have achieved efficient electro-optic phase modulation at high freq uencies in a resonant modulator cavity. We enhance modulation by match ing the phase velocities of the optical and microwave fields in the mo dulator substrate and by placing the modulator inside an optical cavit y that is resonant for the input optical beam and the generated sideba nds. An optical frequency comb with a span of 3 THz and at a spacing o f 17 GHz is generated with 1 W of microwave power. The terahertz comb is utilized to phase lock an optical parametric oscillator at a signal -idler difference frequency of 665 GHz.