A guided-wave optical electric field sensor with improvedtemperature stability

This paper reports on the study of an electric field sensor based on the Y-cut LiNbO₃ waveguide which has slight temperature dependence. The errors in the electric field measurements due to temperature variations were theoretically studied and the increase in the error with a temperature change of 100 K has been proven to be extremely low, 2.5%. As a technology to achieve high temperature stability, we adopted a new method of attaching optical fibers to a waveguide and a method of suppressing the pyroelectric effect by depositing (ITO) In₂O₃-SnO₃ films onto the Z-faces. The temperature dependence of the fabricated sensor was measured and it was found that the measurement errors in a broad temperature range from -30 to 90°C was ±7% or less