A new type of Faraday effect optical current transformer has been developed that uses a single block of square flint glass with dielectric-coated total reflection surfaces as the sensing element. Numerical calculation has shown that the coating of two dielectric layers of 45.59-nm-thick Ta<sub>2</sub>O<sub>5</sub> and 448.35-nm-thick SiO<sub>2</sub> films on a flint glass surface produces zero retardation total reflection for the 45° incident angle of light at λ = 840 nm with great incident angle, wavelength, and film thickness tolerances. A fiber-linked current transformer has been constructed and experimentally demonstrated to exhibit high isolation from surrounding currents as well as high stability against mechanical disturbances.
© 2002 Optical Society of America
Toshihiko Yoshino, Masayuki Yokota, Katsugo Aoki, Ken-ichi Yamamoto, Shun Itoi, and Masatoshi Ohtaka, "Fiber-Linked Faraday Effect Current Sensor by Use of a flint Glass Cell with Dielectric-Coated Retardation-Compensated Total Reflection Surfaces," Appl. Opt. 41, 5963-5968 (2002)