Holographically written reflective polarization filter in single-mode optical fibers.

A new type of internally written grating filter is proposed and demonstrated in single-mode optical fibers. A photoinduced rocking birefringence is created by polarization interference between two counterpropagating and orthogonal linear-polarization modes at 514.5 nm. This birefringent grating has the correct submicrometer pitch for efficient phase-matched reflection of a linearly polarized mode into the orthogonally polarized counterpropagating mode. The phenomenon represents a new form of holography in which the image (the orthogonal counterpropagating mode) is reconstructed by scattering off a hologram consisting of a periodic birefringence.