U-Optics has released an optical isolator, which is a combination of a polarisation beamsplitter cube (PBS) and a quarter waveplate made of crystal quartz.
Incident light is linearly polarised by PBS and converted to circular polarisation by the quarter waveplate. If any portion of the emerging beam is reflected back into the isolator, the quarter waveplate will convert the reflected beam into a linearly polarised beam, which is perpendicular to the input beam. This beam is then blocked by PBS and it will not return to the input side of the system.
Features include: block optical feedback; passive isolation of linearly polarised light; high isolation and RoHS compliance.