Abstract

Dual-mode fibers (DMF) find exciting applications in optical communications and sensors with attractive features that standard single-mode fibers (SMF) do not possess [1]. We report our recent progress on DMF based optical sensors, and show the potential of utilizing the spatial dimension for multi-parameter sensing with discrimination capability. We first show a discrete type Sagnac interferometer (SI) structure with a short SMF, utilizing the interference between counter propagating beams. Then, a dual mode fiber possessing selectively excited LP₀₁ and LP₀₂ modes is incorporated in the Sagnac loop for a simultaneous and a wide dynamic-range measurement of applied transverse stress and twist. The research problem was then analyzed on the avenue of associated theoretical considerations in order to interpret the experimental observation and the resulting accuracy.

© 2015 Japan Society of Applied Physics, Optical Society of America