Abstract

Lithium niobate is a very interesting material for the realization of nonlinear optical devices. A strong limitation to the utilization of wavelength converters based on ferroelectric crystals comes from the photorefractive effect that causes beam distortion and a reduced efficiency of nonlinear interactions. Recent measurements [1] performed by our group have shown that Hafnium-doped LN crystals (Hf:LN) exhibit a significant reduction of photorefractivity. An important step toward the possible utilization of Hf:LN in wavelength converters is the measurement of the effect of Hf doping on the nonlinear properties of the crystals. In this work we present measurements of the second-order nonlinear coefficient d;,i as a function of the Hf concentration for a set of Hf:LN crystals. We recall that the nonlinear coefficient important for application is d₃₃, and not d₃₁. However, several investigations on doped LN crystals have shown that the behaviour of d₃₁ is the same as that of d₃₃.

© 2007 IEEE