between 0 and 90 degrees since the thin film wire grid polarizer 550 was oriented to maximize the reflection of s polarization beam and the transmission of p polarization beam in the basic beam combiner configuration a deviation by angle u03b4 between 0 and 90 degrees will result in partial reflection and transmission of the incident beams as the angle u03b4 changes between 0 and 90 degrees the proportion of the transmitted versus the reflected components of a given polarized incident beam changes continuously when the rotation angle 8 of the thin film wire grid polarizer 550 about the optical axis 515 of the optical pbc s device 500 is between 0 and 90 degrees the optical transmission axis of the wire grid polarizer 550 is no longer aligned to any of the polarization states of the two incident beams this offsets the optical transmission axis of the wire grid polarizer 550 from the optimal condition for reflecting the s polarized incident beam from the fiber 570 and transmitting the p polarized incident beam from the fiber 580 the result is that each incident beam is partially reflected and partially transmitted by the thin film wire grid polarizer 550 and coupled to the output fibers 590 and 593 in order to achieve the most efficient optical coupling from input fibers 570 and 580 to the two output fibers 590 and 593 simultaneously the thin film wire grid polarizer 39 s wire grid structures ideally must be positioned symmetrically with respect to the two collimating focusing lenses 510 and 520 and the gap spacing between the two collimating focusing lenses must be kept to a minimum as previously discussed in reference to fig4 6 because.