Long period grating in multicore optical fiber: an ultra-sensitive vector bending sensor for low curvatures

Pouneh Saffari*, Thomas D.P. Allsop, Adedotum Adebayo, David J. Webb, Roger Haynes, Martin M. Roth

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Long period grating was UV inscribed into a multicore fiber consisting of 120 single mode cores. The multicore fiber that hosts the grating was fusion spliced into a single mode fiber at both ends. The splice creates a taper transition between the two types of fiber that produces a nonadiabatic mode evolution; this results in the illumination of all the modes in the multicore fiber. The spectral characteristics of this fiber device as a function of curvature were investigated. The device yielded a significant spectral sensitivity as high as 1.23 nm/m-1 and 3.57 dB/m-1 to the ultra-low curvature values from 0 to 1 m-1. This fiber device can also distinguish the orientation of curvature experienced by the fiber as the long period grating attenuation bands producing either a blue or red wavelength shift. The finite element method (FEM) model was used to investigate the modal behavior in multicore fiber and to predict the phase-matching curves of the long period grating inscribed into multicore fiber.

Original languageEnglish
Pages (from-to)3508-3511
Number of pages4
JournalOptics Letters
Issue number12
Publication statusPublished - 15 Jun 2014

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