They can split the extraordinary ray and ordinary ray at certain spacing due to its large birefringence when the angle of incidence is 0 degree. It is often used in circulators and interleavers.
||2x2x7mm, 2.6x2.6x10mm, 3x3x15mm
|O.A. Orientation Tolerance:
||<λ/10 @ 632.8nm
||<λ/4 @ 632.8nm
||better than S/D 10/5
||AR Coating:R<0.2%@1310+/40nm, or 1550nm+/-40nm
|| Beter than 10 arcsec