Resonant waveguide quasi-phase-matched SHG devices with electrooptic phase-modulator for tuning

We propose and demonstrate a resonant LiNbO₃ waveguide device for quasi-phase-matched second-harmonic generation (SHG) that employs an electrooptic phase-modulator for frequency tuning. The waveguide cavity for the pump wave consists of an annealed/proton-exchanged channel waveguide and two dielectric mirrors attached to the waveguide facets. SHG experiments were performed using a laser diode at 865-nm wavelength, and a normalized SHG efficiency of 400%/W was obtained. This value is eight times higher than that of a traveling-wave device. The phase modulator allows tuning of the cavity resonance frequency to the pump frequency with a tuning voltage of less than 8.3 V