Integrated Fiber Optic Displacement Sensor Based On Multimode Interference

An integrated fiber-optic displacement sensor based on multimode interference is characterized through analysis of experimental performance in comparison to the expected behavior that is theoretically predicted. Multimode interference and re-imaging theory applied to the specific fiber properties and geometry of the device can be used to design and predict the performance of the device. Essentially, the sensor consists of a multimode fiber of a specific length fusion spliced to a single mode fiber used in conjunction with an 80/20 splitter, source, and detector that are used to inject and detect reflected signals from targets. The sensor is fabricated into a robust, compact, and single arm device capable of operating as a calibrated displacement sensor over a large displacement range. This is achieved through analysis of power reflected off of a surface and back through the device over a finite wavelength range