A miniaturized Faraday isolator magnet structure design for near-infrared wavelength

Faraday isolators are widely used in laser systems. The magneto-optical element in the Faraday isolator has thermally induced depolarization characteristics, which affects the overall performance. The solution is to use a stronger magnetic field and shorter magneto-optical elements. In this paper, a new small-scale Faraday isolator magnet system is designed for using in laser systems with near-infrared wavelengths. The magnet system consists of five magnetic rings that are alternately magnetized in the radial and axial directions. The influence of different magnetic ring configurations on the intensity of the magnetic field was analyzed, and a magnet structure was designed and fabricated. Using this structure, the magneto-optical element is shortened to 7.7 mm under the 780 nm laser. This research is helpful to the development and optimization of the Faraday isolator in the laser system of the near-infrared wavelength.