FLUID LEVEL SENSING DEVICE AND METHOD OF DETERMINING A FLUID LEVEL COMPRISING AN OPTICAL WAVEGUIDE WITH SUCCESSIVE ONES OF CURVED PORTIONS BEING CURVED IN ALTERNATING DIRECTIONS

A fluid level sensing device for determining the level of the interface between a first fluid and a second fluid in a container. The fluid level sensing device comprising an optical waveguide for disposal in the container for at least partial immersion in the first fluid; a light source for providing input light to the optical waveguide; and a light detector for sensing output light from the optical waveguide. The optical waveguide comprises a plurality of curved portions. Successive ones of the curved portions are curved in alternating directions. The optical waveguide is configured such that a curved portion immersed in the first fluid has a greater light loss profile than a curved portion not immersed in the first fluid. The output light from the optical waveguide provides a measure of the level of the interface based on light loss of the input light through the optical waveguide.