Passive polarization-controlled all-fiber gyroscope and other interferometric architectures

A novel all-fiber gyroscope architecture is disclosed making use of the author's U.S.-patented Passive Polarization Control (PPC) invention to stabilize the polarization state of the counter-propagating beams in the rotating Sagnac fiber loop. The PPC is simply a piece of variably spun birefringent optical fiber capable of transforming a circularly polarized light into a linearly polarized light that automatically aligns itself along a principal axis of the fiber. The all-fiber gyroscope architecture uses two cascaded directional couplers operating on circular SOP, thus providing an “SOP matching” with the PPC-terminated fiber loop. Re predicted PPC performance has been confirmed experimentally in a laboratory.