Self referenced intensity-based polymer optical fibre displacement sensor

A self-referenced and tunable optical displacement transducer comprising an optical splitter, at least one transducing element and a self-reference element;

• said optical splitter comprising one inlet and at least two outlets, an optical fiber in the inlet further comprising at least one light source coupled for transmission and split into at least two separated optical paths in the outlets and the proportion of light intensity in each of the outlets compared with the inlet is fixed;
• each of said at least one transducing element comprising a first optical fiber and a second optical fiber, said first optical fiber of the transducing element comprising a first end face aligned along an axis and positioned in one of the outlets of the optical splitter, and a second end face from the outlet of the optical splitter aligned along an axis and positioned with a small gap between said second end face of the first optical fiber and a first end face of a first reception assembly, the small gap at the first reception assembly being filled by a material comprising transparent solid, liquid and gas;
• said transducer further comprising at least one photo-detector coupled for reception to said first reception assembly, said second optical fiber of the transducing element and said first reception assembly being displaceable along said axis and relatively with respect to each other;
• said self-reference element comprising a first optical fiber and a second optical fiber, said first optical fiber of the self-reference element comprising a first end face aligned along an axis and positioned in one of the outlets of the optical splitter, and a second end face from the outlet of the optical splitter aligned along an axis and positioned with a small gap between said second end face and a first end face of a second reception assembly, the small gap at the second reception assembly being filled by a material comprising transparent solid, liquid and gas;
• said transducer further comprising at least one photo-detector coupled for reception to said second reception assembly, said second optical fiber of the self-reference element and said second reception assembly being non-displaceable along said axis.