The ISO-FRDY-04-1030-N Faraday Optical Isolator is essentially a uni-directional light valve. It is used to protect a laser source from destabilizing feedback or actual damage from back-reflected light. This 1030 nm high power free space optical isolator is packaged in a compact cylindrically shaped magneto-optic device with a base plate for ease of mounting into an optical train. It has a 4 mm clear aperture and a 1017 to 1043 nm wavelength range. Horizontal input and 45 degree clockwise polarization output.