Yizheng Chen

Probing Nanostrain via a Mechanically Designed Optical Fiber Interferometer

We propose an extrinsic Fabry–Perot interferometer (EFPI)-based optical fiber sensor with a novel mechanical design for nano-scale strain measurement. In our proposed sensor, a designed mechanical structure consists of a cylinder and a square column attached to a stainless steel substrate. This simple and compact structure along with a fiber ceramic ferrule and a gold-coated reflective mirror as a packaged EFPI sensor can resolve nano-scale strain with temperature self-compensation. In comparison with the existing nanostrain sensing methods, no reference sensors and complicated configurations are needed. The strain measured by our proposed sensor ranges from 0 to 677 <inline-formula> <tex-math notation=LaTeX>

A Displacement Sensor With Centimeter Dynamic Range and Submicrometer Resolution Based on an Optical Interferometer

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An Optical Interferometric Triaxial Displacement Sensor for Structural Health Monitoring: Characterization of Sliding and Debonding for a Delamination Process

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An embeddable optical strain gauge based on a buckled beam

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Displacement and Strain Measurement up to 1000 °C Using a Hollow Coaxial Cable Fabry-Perot Resonator

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A hollow coaxial cable Fabry–Pérot resonator for liquid dielectric constant measurement

We report a low cost and extrinsic Fabry-Perot interferometer-based optical fiber displacement sensor with a wide dynamic range, up to 2.0 cm, and

A Microwave Photonics Fiber Loop Ring-Down System

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Probing changes in tilt angle with 20 nanoradian resolution using an extrinsic Fabry-Perot interferometer-based optical fiber inclinometer

resolution. The fundamental design principle includes an inclined mirror, mounted on a translational stage, that combines with the end face of a single mode fiber to form a Fabry-Perot cavity. The user-configurable triangle geometry-based displacement transfer mechanism makes the sensor capable of measuring a wide displacement range. A fiber ceramic ferrule is used to support and orient the optical fiber, and a metal shell is used to package and protect the principal sensor elements. The novel sensor was employed to monitor shrinkage during the drying/curing stage of a square brick of mortar. The robust and easy-to-manufacture sensor can be easily commercialized and has great potential for applications in the chemical-oil industry, construction industry, and other industries with harsh environments.

An Embeddable Strain Sensor with 30 Nano-Strain Resolution Based on Optical Interferometry

This paper presents an extrinsic Fabry–Perot interferometer-based optical fiber sensor (EFPI) for measuring three-dimensional (3D) displacements, including interfacial sliding and debonding during delamination. The idea employs three spatially arranged EFPIs as the sensing elements. In our sensor, the three EFPIs are formed by three endfaces of three optical fibers and their corresponding inclined mirrors. Two coincident roof-like metallic structures are used to support the three fibers and the three mirrors, respectively. Our sensor was calibrated and then used to monitor interfacial sliding and debonding between a long square brick of mortar and its support structure (i.e., a steel base plate) during the drying/curing process. This robust and easy-to-manufacture triaxial EFPI-based 3D displacement sensor has great potential in structural health monitoring, the construction industry, oil well monitoring, and geotechnology.

A Uniform Strain Transfer Scheme for Accurate Distributed Optical Fiber Strain Measurements in Civil Structures

We report, for the first time, a low cost, compact, and novel mechanically designed extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber sensor with a strain amplification mechanism for strain measurement. The fundamental design principle includes a buckled beam with a coated gold layer, mounted on two grips. A Fabry-Perot cavity is produced between the buckled beam and the endface of a single mode fiber (SMF). A ceramic ferrule is applied for supporting and orienting the SMF. The principal sensor elements are packaged and protected by two designed metal shells. The midpoint of the buckled beam will experience a deflection vertically when the beam is subjected to a horizontally/axially compressive displacement. It has been found that the vertical deflection of the beam at midpoint can be 6-17 times larger than the horizontal/axial displacement, which forms the basis of a strain amplification mechanism. The user-configurable buckling beam geometry-based strain amplification mechanism enables the strain sensor to achieve a wide range of strain measurement sensitivities. The designed EFPI was used to monitor shrinkage of a square brick of mortar. The strain was measured during the drying/curing stage. We envision that it could be a good strain sensor to be embedded in civil materials/structures under a harsh environment for a prolonged period of time.