Synthesis Of Interference Patterns In Few-Mode Optical Fibers

Abstract

When a single-mode fiber is operated at a wavelength shorter than its nominal wave-lenght, few lower-order modes are excited and an interference pattern develops which is sensitive to differential phase variations of the modes. Intensity patterns resulting from the interference of the pairs of modes LPoi, LP11 and LP11, LP21 are examined. By proper choices of phase and amplitude of the interfering modes, one,two and three-lobe patterns can be synthesized which exhibit oscillatory or rotational behavior in response to an external disturbance. Launching conditions for achieving such patterns are discussed. Sensor applications of few-mode fibers, particularlyfor strain and temperature sensing, are addressed.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.