MEASUREMENT OF QUADRATIC ELECTROOPTIC COEFFICIENTS IN LINBO3 USING A VARIATION OF THE FDEOM METHOD

Calculations on the optical index ellipsoid yield that in LiNbO3, a quadratic electrooptic effect free of its linear counterpart exists only for propagation along the X-crystal axis with a longitudinal electric field and in that case the quadratic coefficients R(c) = R12 - R31 and R41 are exclusively involved. Because of their low values, we have measured these coefficients using a specific novel variation of the accurate frequency-doubling electrooptic modulation (FDEOM) method. After a presentation of the theoretical formulation and practical implementation of this method, results for R(c) and R41 are given and discussed in relation to theoretically expected values.