A curvature fiber optic sensor using a two-core fiber (TCF) is proposed and demonstrated. The TCF, which is designed to allow coupling between the cores, acts as a directional coupler and thus offers sinusoidal spectral response. The sensor is fabricated by splicing a 50 mm-long section of TCF between two SMFs. When the fiber is bent, the coupling coefficient between the cores is modified mainl...

Aircraft operators are faced with increasing requirements to extend the service life of air platforms beyond their designed life cycles, resulting in heavy maintenance and inspection burdens as well as economic pressure. Structural health monitoring (SHM) based on advanced sensor technology is potentially a cost-effective approach to meet operational requirements, and to reduce maintenance cost...

A distributed sensor system is highly desirable for detecting, locating, and monitoring fine cracks at unknown locations in advanced ceramics. This paper presents a distributed high-resolution fiber optic sensor based on the Brillouin scattering principle, and its application in ceramic crack detection for the first time. The existence of cracks, together with their locations, is identified by ...

A reflective type fiber optic angular displacement sensor has recently been developed, which consists of a light source, an optical isolator, a four-port single-mode fiber bidirectional coupler, and a light intensity detection system (two silicon photodetectors and ananalog divider). By using a normal He-Ne laser with &2% stability in light intensity, we have achieved an angle resolution of 10e...

(Abstract) The health monitoring of smart structures in civil engineering is becoming more and more important as in-situ structural monitoring would greatly reduce structure life-cycle costs and improve reliability. The distributed strain and temperature sensing is highly desired in large structures where strain and temperature at over thousand points need to be measured simultaneously. It is d...

This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS) and biosensors (FOBS). Fiber optic sensor (FOS) systems use the ability of optical fibers (OF) to guide the light in the spectral range from ultraviolet (UV) (180 nm) up to middle infrared (IR) (10 μm) and modulation of guided light by the parameters of the surrounding environment of the OF...