Compact Faraday optical isolators on the base of multisector permanent magnet systems

Abstract

Faraday optical isolator is used in laser systems with amplifiers to protect master oscillator from reflected and backscattered amplified light. The main part of FOI is a magnet system with magneto-optical glass. For traditional magnet systems of two or several alternative toroidal magnets it was shown that with growth of inner radius length and mass increase. Besides that axial magnetic field of such systems does not exceed remanence of magnetic material. The goal of this paper was to solve this problem by constructing Faraday optical isolator on the base of multisector permanent magnets, the practical realization of magnets with non-uniform magnetization. On the base of those magnets, spherical and toroidal permanent magnet systems were constructed. For toroidal systems constructed on the base of multisector magnet with inner and outer radiuses <i>r1</i> = 0.6 cm, <i>r2</i> = 3.6 cm, length <i>l</i> = 1 cm and remanence of magnetic material <i>B</i> = 12 kOe axial magnetic field <i>H</i> = 14.4 kOe was calculated. For spherical systems constructed on the base of the same magnet axial magnetic field <i>H</i> = 19.6 kOe was calculated. The research of toroidal and spherical multisector magnet systems showed that they can be used for constructing of compact Faraday optical isolators.