Two-Dimensional Displacement Sensor with High Resolution and Simple Structure

A low-cost, high-sensitivity, two-dimensional (2D) displacement sensor based on the alignment of a single-mode fiber (SMF) and a four-core fiber (FCF) has been proposed. The emission light from the SMF is irradiated onto the end surface of the FCF. The power captured by each individual core of the FCF is directly influenced by the spatial relationship between the SMF and the FCF. When the SMF undergoes displacement, the power received by each core of the FCF changes, and the direction of the displacement can be determined according to the power variation. The practicality of this configuration has been substantiated through computational modeling and experimental testing. This sensor is capable of not only quantifying the extent of displacement but also discerning its direction. It has achieved a remarkable resolution of up to 8 nanometers. The sensor introduced here is characterized by its simple structure, easy construction, and high accuracy.