FREQUENCY TUNING A MIDINFRARED OPTICAL PARAMETRIC OSCILLATOR BY THE ELECTROOPTIC EFFECT

Controlled frequency tuning of an optical parametric oscillator is acc omplished through the application of a de electric field that perturbs the index ellipsoids for the pump, the signal, and the idler beams by means of the linear electro-optic (Pockels) effect. The changes in th e refractive indices induce a dispersion-compensating wavelength tunin g of the optical parametric oscillator signal and idler beams to maint ain the birefringent phase-matching condition. Broadband wavelength tu ning by the electro-optic effect in a mid-infrared lithium niobate opt ical parametric oscillator is demonstrated. A linear dependence of the wavelength shift on applied voltage is observed with an idler tuning range of up to similar to 90 nm achieved electro-optically. Tuning rat es in excess of 5 cm(-1)/(kV/cm) are obtained. All observations, inclu ding the dispersion in the tuning rate, are quantitatively described b y a simple theory that uses no adjustable parameters. (C) 1997 Optical Society of America.