Disclosed is a polarization beam splitter which has; a lithium niobate or lithium tantalate substrate which has an in-plane optical axis; proton exchanging regions formed periodically on a surface of the substrate; and phase compensating film regions formed periodically on the proton exchanging regions;...http://www.google.com.au/patents/US6046851?utm_source=gb-gplus-sharePatent US6046851 - Polarization beam splitter and method for making the same
