A new method for measuring the electro-optic coefficients with higher sensitivity and higher accuracy

Abstract

A new method for measuring electrooptic coefficients of nonlinear crystals has been developed and used to obtain an accurate measurement of r33 and r13 for Strontium Barium Niobate (SBN). An electrooptic modulator was used with a Michelson interferometer for ac modulation (sub-Hz to MHz). By observing the appearance and symmetrical shape of the second harmonic of the ac modulation, the electrooptic coefficients r33 and r13 of SBN were measured with higher accuracy. The unclamped electrooptic coefficients of poled of SrxBa1-xNb2O6 single crystal are: r33=237±3 pm/V and r13=37±1 pm/V, at λ=632.8 nm and T=21°C. In addition the piezoelectric coefficient d23 has been measured with d23=25±5pm/V. © 1991.