Fabrication and Characterization of a Flexible FBG-Based Shape Sensor Using Single-Mode Fibers

Samaneh Manavi Roodsari, Sara Freund, Azhar Zam, Georg Rauter, Philippe Cattin

Research output: Contribution to journalArticlepeer-review


Minimally invasive surgical procedures have become the preferable option, as the recovery period and the risk of infections are significantly lower than traditional surgeries. However, the main challenge in using flexible tools for minimal surgical interventions is the lack of precise feedback on their shape and tip position inside the patient's body. Shape sensors based on fiber Bragg gratings (FBGs) can provide accurate shape information depending on their design. One of the most common configurations in FBG-based shape sensors is to attach three single-mode optical fibers with arrays of FBGs in a triangular fashion around a substrate. Usually, the selected substrates dominate the bending stiffness of the sensor probe, as they have a larger diameter and show less flexibility compared to the optical fibers. Although sensors with this configuration can accurately estimate the shape, they cannot be implemented in flexible endoscopes where large deflections are expected. This paper investigates the shape sensor's performance when using a superelastic substrate with a small diameter instead of a substrate with dominating bending stiffness. A generalized model is also designed for characterizing this type of flexible FBG-based shape sensor. Moreover, we evaluated the sensor in single and multi-bend deformations using two shape reconstruction methods.

Original languageEnglish (US)
Pages (from-to)2488-2498
Number of pages11
JournalIEEE Transactions on Biomedical Engineering
Issue number8
StatePublished - Aug 1 2022


  • fiber Bragg grating (FBG)
  • fiber sensor characterization
  • Minimally invasive surgery
  • optical fiber shape sensing
  • sensors for flexible endoscope

ASJC Scopus subject areas

  • Biomedical Engineering


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