Patent ID: 6930475

Claim:
A method for measurement of an electrical voltage V using an electrooptical medium, with the electrooptical medium being subjected to an electric field which is dependent on the voltage V and with at least two polarized light beams of different wavelengths (λ 1 , λ 2 ) being injected into the electrooptical medium, and with output signals A 1 and A 2 of the light beams being measured, where A 1 and A 2 are temperature-dependent functions ƒ 1 and ƒ 2 of the voltage V, and with a search being carried out for those values of the temperature T and of the voltage V which solve the equation system A 1 =ƒ 1 ( T, V ) and A 2 =ƒ 2 ( T, V ) wherein the at least two polarized light beams are analyzed after passing through the electrooptical medium, wherein the voltage dependency of the refractive-index change is described by an effective electrooptical coefficient r or by a combined electrooptical term R where R=n 3 r, with n being the refractive index of the medium, wherein a known temperature dependency r=r(T) or R=R(T) is assumed for the effective electrooptical coefficient r or for the combined electrooptical term R, wherein the known temperature dependency r=r(T) of the effective electrooptical coefficient r or R=R(T) of the combined electrooptical term R is inserted into the equation system, with the temperature T and the voltage V thus being calculated, and in that the functions ƒ 1 and ƒ 2 depend on the voltage V in a non-unique way, and in that that voltage V for which both equations in the equation system are satisfied is determined.