Fiber Cross-Coupling Mechanisms in Optical Pressure Sensor Arrays

The principle of a force-induced coupling of light between two crossing optical fibers is investigated for the application in a pressure sensor, which can be integrated into textile surfaces, which can be implemented into seats, furniture or in industrial areas. The influence of the applied force, the losses at the coupling point and the relative alignment of the two fibers are studied in detail. It is found that most of the light is not captured by the sensing fiber, but can be strongly increased by a proper alignment of the crossing angle between the fibers, which lead to a sensitivity gain of 21.6 dB.