Optical fibre probe with lateral interface

This paper proposes a novel optical fibre probe containing a scattering layer that is capable of sensing the surrounding light through the lateral surface of the fibre. The performance of the probe in sensing various target objects in free space and water environment has been evaluated by ray-trace simulation. For the probe of diameter 1 mm and length 50 mm, the normalised power, which is defined as the ratio of the signal power to the source power, was obtained within 0.1–0.01 % for the target object over a surrounding space with a radius of ~20 mm. Besides, the probe exhibits sharp directional property with an angular diameter of ~10° in the radial direction. Utilizing this functionality, the probe with the spiral-shaped scattering part will enable the sensing of target objects that are spatially distributed along a fibre axis with a minimum detectable gap of less than 2 mm.