Optical Isolator (OI)

• Blocks the return path of an optical beam

Optical isolators are a combination of a linear polarizer and a Quartz quarter wave retardation plate. Incident light is linearly polarized by the polarizer and converted to circular polarization by the quarter waveplate. If any portion of the emerging beam is reflected back into the isolator, the quarter wave plate produces a beam, which is linearly polarized perpendicular to the input beam. This beam is blocked by the linear polarizer and not returned to the input side of the system. These optical isolators are manufactured using a polarizing cube beamsplitter and a Quartz quarter wave plate. They are anti-reflection coated for the wavelength of interest.