What's the working principle of optical isolator ?
Optical isolator is mainly the use of magneto-optic crystal Faraday effect. Faraday effect is Faraday first observed in 1845 does not have optical activity of the materials under magnetic field is made by the material of light polarization direction of rotation, also known as the magneto optical effect. Along the magnetic field direction of transmission of the polarized light, the polarization rotation Angle theta and the direction of the magnetic field strength B and material length L is proportional to the product. 

For positive incidence signal light, through the analyzer, then become a linear polarized, ferrari brother gyromagnetic medium with external magnetic field to the polarization direction of the signal light right 45 degrees, and to make low loss with the partial 45 degrees of partial detector. To reverse the light, the linear polarization deflection detector