Birefringence elimination of bismuth germanate crystal in quasi-reciprocal reflective optical voltage sensor

Bismuth germanate (Bi₄Ge₃O₁₂, BGO) has been widely utilized for the application of Pockels effect-based voltage and electric field sensors, because it possesses no unwanted effects ideally. However, there are multiple birefringences in BGO crystal induced by natural imperfections, temperature-dependent strain, and external pressure (or stress), which influences the demodulation of the Pockels effect induced by the voltage to be measured. For a Pockels effect-based quasi-reciprocal reflective optical voltage sensor, the influences of the multiple birefringences in BGO crystal are investigated and an elimination scheme is also proposed in this paper. The feasibility of the proposed elimination scheme is simulated and experimentally verified.