Displacement sensor based on a large-core hollow fiber and specklegram analysis

The research enterprise towards achieving high-performance hollow-core photonic crystal fibers has led to impressive advancements in the latest years. Indeed, using this family of fibers becomes nowadays an over-arching strategy for building a multitude of optical systems ranging from beam delivery devices to optical sources and sensors. In most applications, an effective single-mode operation is desired and, as such, the fiber micro-structure or the light launching setups are typically designed for achieving such a behavior. Alternatively, one can identify the use of large-core multimode hollow-core fibers as a promising avenue for the development of new photonic devices. Thus, in this manuscript, we propose and demonstrate the utilization of a large-core tubular-lattice fiber for accomplishing a speckle-based displacement sensor, which has been built up by insert-ing and suitably dislocating a single-mode fiber inside the void core of the hollow fiber. The work reported herein encompasses both simulation and experimental studies on the evolution of the multimode intensity distributions within the device as well as the demonstration of a displacement sensor with an estimated resolution of 0.7 mu m. We understand that this investigation identifies a new opportunity for the employment of large-core hollow fibers within the sensing framework hence widening the gamut of applications of this family of fibers.

Automated summary

The research on high-performance hollow-core photonic crystal fibers has achieved impressive progress, making it a common strategy for building various optical systems. This paper proposes and demonstrates a speckle-based displacement sensor using a large-core tubular-lattice fiber, which has been inserted with and suitably displaced a single-mode fiber. Both simulation and experimental studies have been conducted, showing a displacement resolution of 0.7 μm. This investigation identifies a new opportunity for the application of large-core hollow fibers in the sensing framework, expanding the range of applications for this fiber family.