We describe the design, construction, and application of what are believed to be the smallest fiber-optic probes used to date during imaging or diagnosis involving low-coherence interferometry (LCI). The probes use novel fiber-optic gradient-index (GRIN) lenses fabricated by a recently developed modified chemical-vapor-deposition (MCVD) process that avoids on-axis aberrations commonly marring M...

Abstract Fiber-optic hydrophone (FOH) is a significant type of acoustic sensor, which can be used in both military and civilian fields such as underwater target detection, oil natural gas prospecting, earthquake inspection. The recent progress FOH introduced from five aspects, including large-scale array, very-low-frequency fiber-optic vector (FOVH), towed linear deep-sea long-haul transmission...

Detection and quantification of cracks for various civil infrastructures on a large scale are difficult both technologically economically through current sensing methodologies. This study presents novel fiber-optic sensor named short-gauged Brillouin fiber optic sensor, which enables basic Brillouin-based analyzers to achieve early crack detection accurate width measurement. The concept design ...

This study investigates new methods to improve deepwater monitoring and addresses installation of advanced sensors on ”already deployed” risers, flowlines, trees, and other deepwater devices. A major shortcoming of post installed monitoring systems in subsea is poor coupling between the sensor and structure. This study provided methods to overcome this problem. Both field testing in subsea envi...

We describe respiration monitoring in sleep using hetero-core fiber optic pressure sensors. The proposed hetero-core fiber optic sensor is highly sensitive to macrobending as a result of the core diameter difference due to stable single-mode transmission. Pressure sensors based on hetero-core fiber optics were fabricated to have a high sensitivity to small pressure changes resulting from minute...

In this paper a method to track the rotating force vector set up within the air-gap of radial flux rotating electrical machines using fibre Bragg gratings is reported. The proposed technique offers the potential for simultaneous rotor speed and position monitoring. This specific sensor design, together with other FBG-based multi-parameter measurements, is aimed to create an all-optical sensor s...

In the last 15 years, fiber optic sensing has become a useful and increasingly widely used tool for structural health monitoring of bridges and other civil structures. We have been fortunate to participate to their development and introduction to real field applications. This paper is an overview of 40 bridge monitoring projects carried out over the last 15 years in 13 different countries. In p...

The measurement of surface curvature is great significance in aerospace, structural health monitoring, energy batteries, etc. In this paper, a fiber-optic sensor, based on intracavity sensing fiber ring laser (FRL), experimentally demonstrated. A no-core fiber- filter performs as the head FRL sensor. response between NCF and output wavelength was investigated. curvature, sensor system showed na...