Split magnet Faraday rotator and polarization-independent laser isolator

Abstract

The invention discloses a split-type magnetic steel Faraday rotator and a polarization independent isolator laser. The Faraday rotator comprises two sets of magnetic steel and a magneto-optical crystal, the two sets of magnetic steel are arranged side by side, each set of magnetic steel is of a magnetic ring structure formed by enclosing of even numbers of fanned magnetic blocks, each fanned magnetic block is radially magnetized, south poles of the fanned magnetic blocks in the two sets of magnetic steel are close to the center end / away from the center end, north poles are away from the center end / close to the center end, the south poles and the north poles of the two sets of magnetic steel are arranged oppositely, and the magneto-optical crystal is located between the two sets of magnetic steel. An internal magnetic field of the magnetic steel is larger than that of an existing magnetic ring under the condition of same magnetization, so that a smaller magneto-optical crystal can be used, materials are saved, cost is lowered, and small size is achieved; meanwhile, an external magnetic field is lowered, and affection of the magnetic steel on external iron materials is reduced.

Description

technical field [0001] The invention relates to a polarization-independent laser isolator, specifically a Faraday rotator, which is a core component in the polarization-independent laser isolator, and a polarization-independent laser isolator with the Faraday rotator, belonging to the field of magneto-optical technology. Background technique [0002] The polarization-independent laser isolator uses the Faraday effect of the magneto-optic crystal to realize the one-way transmission function of the laser. It is composed of a birefringent crystal 1, a 1 / 2 wave plate and a Faraday rotator 2. Its principle is as follows figure 1 and figure 2 shown. [0003] Forward input light (eg figure 1 (shown by the solid line in the center) when entering the first birefringent crystal, the light is divided into 0 light and e light whose polarizations are perpendicular to each other, and the two polarized lights pass through the Faraday rotator and the 1 / 2 wave plate. The polarization dir...

AI Technical Summary

Problems solved by technology

from image 3 It can be seen that the magnetic induction line density distribution inside and outside the traditional magnetic ring magnet is uniform, and the internal and external magnetic field strengths are consistent, but what can really be used is the central internal magnetic field, so its magnetic field utilization is relatively low. Under the same magnetization conditions , a longer magneto-optic crystal is needed to meet the requirement of rotating the polarization direction by 45°

At the same time, since the external magnetic flux density is as large as the internal magnetic flux density, to increase the internal magnetic field strength, the external magnetic field strength should also be increased accordingly, resulting in a strong attraction of the magnetic steel to the external ferrous material

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