Optical polarizer having a dielectric multiple layer system

Abstract

An optical isolator for glass fiber communication technology, which avoids disruptive back reflections at the input side polarizer that faces a laser diode, consists of a dielectric alternating layer system that is glued between a pair of prisms. In order to obtain a reflection-free polarizer for linear polarized radiation arriving at a specific angle of incidence, the material of the prisms and layers are selected so that the index of refraction of the prisms is equal to the index of refraction of the layers having a low index of refraction and the angle of incidence of radiation at the radiation entrance surface as well as the angle of emergence at the radiation exit surface of the prism are selected to equal the Brewster angle which is given by the arc tan (n.sub.L /n.sub.O) wherein n.sub.L is the low index of refraction of the layer and prisms and n.sub.O is the index of refraction of the medium adjacent to the prisms exit and entrance surfaces.