Optical Bend Sensor Based on Eccentrically Micro-Structured Multimode Polymer Optical Fibers

authored by

Lennart Leffers, Julia Locmelis, Kort Bremer, Bernhard Roth, Ludger Overmeyer

Abstract

We report on a novel bend sensor with high flexibility and elasticity based on Bragg grating structures in polymer optical fibers to detect bending for the measurement of movement. The concept is very simple and relies on the inscription of eccentrical Bragg gratings into multimode graded-index polymer optical fibers via contact exposure with a krypton fluoride excimer laser in the ultraviolet region and an optimized phase mask. Depending on the fiber deformation, the lattice constant of the inscribed Bragg grating is strained or compressed due to its position relative to the fiber core. This in turn results in a specific shift of the Bragg wavelength of up to 1.3 nm to the red or blue wavelength region, respectively, which is sufficiently large to be reliably detected. Therefore, as proof of principle, deformation along one axis can be observed with a single Bragg grating with a maximum sensitivity of up to 65 pm/m-1. Moreover, multiple Bragg gratings inscribed into the same polymer optical fiber at different positions around the fiber axis allow to determine the shape deformation of the fiber relative to a reference frame with similar accuracy. Consequently, this technology could form the basis for new applications in the areas of medical diagnostics, robotics or augmented reality, which are lacking affordable sensor systems to date.

Organisation(s)

Hannover Centre for Optical Technologies (HOT)
PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines
Institute of Transport and Automation Technology

Type

Article

Journal

IEEE photonics journal

Volume

13

ISSN

1943-0655

Publication date

09.09.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

Electronic version(s)

https://doi.org/10.1109/JPHOT.2021.3111298 (Access: Open)