高功率光隔离器永磁系统的理论研究与优化

基于Halbach阵列永磁体的特点以及光隔离器对磁场的需求,设计了两种适用于高功率隔离器的永磁系统,分析了其磁场分布、磁场非均匀性对隔离度的影响,研究了磁体装配误差对磁场的影响。研究结果表明:通过引入斜向磁化永磁体,选择合适的磁化角度和磁体长度,可以提高永磁体的磁场强度,大幅度减小旋转器所需磁光晶体长度;受磁场非均匀性影响的隔离度与磁光晶体的孔径、长度以及入射激光的光斑半径有关,当晶体长度一定时,减小晶体半径和入射光的半径可以显著提高隔离度。在入射光半径为1.5mm、磁光晶体半径5mm时,对应的隔离度分别为105.8dB和45.4dB。

Theoretical study and optimization design of high-power optical isolator permanent magnet system

Based on Halbach array permanent magnets and the magnetic field demand of optical isolator, two permanent magnet systems for high power isolator are presented. The magnetic field distribution characteristics and the effect of magnetic field inhomogeneity on isolation are analyzed. The magnet assembly error is also discussed. The results show that, the use of oblique magnetization magnet can increase the magnetic field intensity and drastically reduce the required magnetooptic crystal length of Faraday rotator. And the isolation affected by magnetic field inhomogeneity is related to magneto optic crystal aperture, length and the incident laser beam radius, it can be significantly improved by reducing crystal radius and beam radius while magneto-optic crystal length is fixed. The isolation degree is 105.8 dB and 45.4 dB respectively for the proposed two permanent magnet systems, when the radius of incident light is 1.5 mm and magneto-optic crystal radius is 5 mm.