Fiber-optic ring interferometer with a multimode waveguide

Polarization and spatial information recovery by modal dispersal and phase conjugation: properties and applications

“…Sagnac interferometers have usually been employed for this purpose because they are inherently insensitive to reciprocal phase shifts but are sensitive to nonreciprocal phase shifts [60], [64]. Multimode fiber-optic gyros have also been proposed [72], [73], but their sensitivity is limited by the modal scrambling in the fiber. For obtaining better sensitivity over some unwanted perturbations such as modal scrambling and Faraday effects, single-mode polarization-preserving fibers and couplers have been used [74].…”

Investigation of mode coupling effects on sensitivity and bias of a multimode fiber loop interferometer: Application to an optimal design of a multimode fiber gyroscope

“…The first MFOG realized at that time, were laboratory demonstrators using bulk optical components, such as beam-splitters and microscope objectives [21][22][23][24]. These optical components must be aligned with each other, giving a critical arrangement incompatible with mechanical vibrations and inducing non-rotationally phase error.…”