The Design Principle of Magneto Optical Switch

Compared with the traditional mechanical optical switch, the magneto optical switch has the advantages of fast switching speed and high stability. Compared with other non-mechanical optical switches, the magneto optical switch has the advantages of low driving voltage and small crosstalk. In the near future, the magneto optical switch will be a very competitive product.

The design principle of magneto optical switch:

The Faraday rotation effect has been applied to the magneto optical switch. Changing the effect of magneto-optic crystal on incident polarized light and polarized plane by adding the external magnetic field, so as to achieve the effect of switching optical path. In other words, the Faraday rotation effect is the phenomenon that the polarization plane rotates when linearly polarized light passes through a medium in the direction of an external magnetic field. For a linearly polarized light along the M direction in the medium, it can be divided into two circularly polarized lights that are in the opposite direction. If it is a real number, it means that the medium does not absorb the light wave. And then the two circularly polarized lights propagate forward at two slightly different velocities without any interaction. After irradiating, there is only a phase difference between them. Therefore, the resultant light is still linearly polarized, but its polarization plane rotates to a certain extent compared with the incident polarized light. This explains that when the external magnetic field acts on the magneto-optical crystal, its polarization state can be changed after the polarization light passes through.

The magneto optical switch can realize the all-optical switching function which is necessary for all-optical communication.