Two-axis bend measurement with Bragg gratings in multicore optical fiber

Abstract

This version is available at https://strathprints.strath.ac.uk/42768/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. We describe what is to our knowledge the first use of fiber Bragg gratings written into three separate cores of a multicore fiber for two-axis curvature measurement. The gratings act as independent, but isothermal, fiber strain gauges for which local curvature determines the difference in strain between cores, permitting temperature-independent bend measurement.

Bio-inspired all-optical artificial neuromast for 2D flow sensing

“…The thermal effect can be compensated using differential strain configurations in which the thermal effect is common to all considered gratings (Flockhart et al 2003). Both the local Bragg wavelength shifts (i.e.…”

“…This requires the gratings to be located outside the neutral (bending) axis of a cantilever structure. Examples of FBG curvature sensors (Flockhart et al 2003) and accelerometers (Fender et al 2007) have also been developed using multicore optical fibres with multiple cores positioned away from the neutral axis.…”

Transverse loading of multicore fibre gratings

“…The fibre cross-section is illustrated in Figure 1 . The circular cross-section is particularly important for fibre handling, and we have observed that higher quality cleaves can be obtained using this fibre in contrast to other (noncircular) multicore fibres that we have tested previously [7]. This has allowed us to make low-loss (<1dB) splices between lengths of multicore fibre using a Vytran splicer with fibre rotation and alignment facility.…”

“…This has allowed us to make low-loss (<1dB) splices between lengths of multicore fibre using a Vytran splicer with fibre rotation and alignment facility. The intrinsic photosensitivity of this multicore fibre permits UV-inscription of the FBG structures in the cores without hydrogenation of the fibre -an essential treatment for grating fabrication in standard telecom and the non-circular fourcore fibres that we have used in previous work [7]. We have produced high-efficiency FBGs in this multicore fibre using the standard phase mask scanning technique [8] and a frequency doubled Ar laser with a 95mW output at 244nm.…”

“…We have previously reported the use of FBGs written in several cores of MCF to measure structural bending [7]. The axial strain imposed by bending the fibre is measurable as a differential shift in the Bragg wavelengths between pairs of cores within the fibre.…”