Abstract

Typically, wavelength tuning in a birefringently phase-matched optical parametric oscillator (OPO) is accomplished by adjusting the angle of propagation in the nonlinear optical crystal. However, angle tuning is not the only way to alter the wavelength of an OPO; other physical mechanisms such as temperature, pressure or electric field^1,2 that change the refractive indices (or more specifically, the birefringence) will induce a corresponding dispersion-compensating change in wavelength to maintain phase matching. Electro-optically tuning an OPO is particularly attractive since it is non-mechanical (does not involving any moving parts) and can be done rapidly. Previously, electro-optic tuning was used to compensate for the phase mismatch from self-heating in CD*A during second-harmonic generation.³ More recently, frequency stabilization in a doubly-resonant OPO configuration with KTP was accomplished using electro-optic tuning.⁴ Here, we describe the first demonstration of broadband wavelength tuning in an OPO via the electro-optic effect in LiNbO₃. The method is then applied to KNbO₃ since it has much larger electro-optic coefficients. A comparison of electro-optic tuning range and tuning rate for LiNbO₃ and KNbO₃ are also discussed.

© 1996 Optical Society of America