Prism polarizer

An optical circulator comprising:

• two prism polarizers for separating incident light beams having P-polarization and S-polarization light rays, each prism polarizer including
• a pair of anisotropic crystal prisms, wherein each prism has a boundary surface, the boundary surface of a first prism of said pair faced to the boundary surface of the second prism, thus defining a facing plane;
• wherein each prism comprises a crystal which has an optical axis such that the difference between the square of the refractive index for light rays having a polarization plane parallel to the optical axis, and the square of the refractive index for light rays having a polarization plane perpendicular to the optical axis, is larger than 1;
• the angle of incidence of a beam, exiting one of said prisms, upon the boundary surface of said beam-exiting prism being equal to the Brewster angle for the refractive index for the P-polarization rays,
• so that the P-polarization rays are transmitted through said boundary surface of said beam-exiting prism, while the S-polarization rays are totally reflected at said boundary surface of said beam-exiting prism, thereby said incident beam being separated into two polarized beams, and
• wherein each prism of said pair of prisms has an inlet end surface and an outlet end surface, and each of said two separated polarized beams is totally reflected within each respective prism and the separated polarized beams exit said respective prisms parallel with each other;
• the outlet end surfaces of said two polarizers are faced to each other;
• a rotatory polarization device disposed between the two polarizers and arranged so that said device rotates the polarization plane of a polarized beam from one direction by 90.degree., while said device does not rotate the polarization plane of a polarized beam from the reverse direction;
• and wherein said inlet end surfaces of said prisms are used as an inlet and an outlet of said optical circulator.