National Engineering Laboratory for Fiber Optic Sensing Technology

Wuhan, China

National Engineering Laboratory for Fiber Optic Sensing Technology

Wuhan, China

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Tian M.,Applied Technology Internet | Tian M.,Huazhong University of Science and Technology | Lu P.,Applied Technology Internet | Lu P.,Huazhong University of Science and Technology | And 6 more authors.
Optics Communications | Year: 2014

A compact micro multicavity Fabry-Perot (FP) optical fiber tip sensor is presented. In the end of the single-mode fiber (SMF), we drill a short air hole with femtosecond laser, which forms a multicavity together with the fiber flat face tip. The sensor has been experimentally tested for refractive index (RI) and temperature sensing by monitoring its wavelength shift. Simultaneous measurement of both changes in the ambient temperature and the RI can be realized using the sensitivity matrix. Measurement results show that the in-line FP exhibits the gas RI sensitivity of 867.76 nm/RIU and the temperature sensitivity of 7.8 pm/ C within the range of 24-104 C, and the device is highly stable over time. © 2013 Elsevier B.V.


Lu J.,National Engineering Laboratory for Fiber Optic Sensing Technology | Lu J.,Wuhan University of Technology | Song P.,Wuhan University of Technology | Han K.,National Engineering Laboratory for Fiber Optic Sensing Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

This paper present an improved imaging algorithm for bridge crack detection, through optimizing the eight-direction Sobel edge detection operator, making the positioning of edge points more accurate than without the optimization, and effectively reducing the false edges information, so as to facilitate follow-up treatment. In calculating the crack geometry characteristics, we use the method of extracting skeleton on single crack length. In order to calculate crack area, we construct the template of area by making logical bitwise AND operation of the crack image. After experiment, the results show errors of the crack detection method and actual manual measurement are within an acceptable range, meet the needs of engineering applications. This algorithm is high-speed and effective for automated crack measurement, it can provide more valid data for proper planning and appropriate performance of the maintenance and rehabilitation processes of bridge. © 2012 SPIE.


Wang J.,National Engineering Laboratory for Fiber Optic Sensing Technology | Wang J.,Wuhan University of Technology | Zhou C.,National Engineering Laboratory for Fiber Optic Sensing Technology | Zhou C.,Wuhan University of Technology | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

A novel magnetic field sensor consisting of magnetic fluid (MF) and etched highly birefringent fiber loop mirror (Hi-Bi FLM) is proposed in the paper. The sensor is based on the etched FLM interferometer by using the property of the controllable refractive index of MF under external magnetic field. The refractive index of MF is changed by a tunable magnetic field and the resonant dip wavelength produced by the FLM shifts correspondingly. The magnetic field intensity can be measured by detecting wavelength shift. High sensitivity of 11.31pm/Oe and a resolution of 0.1Oe are obtained for the proposed magnetic field sensor. © 2014 SPIE.


Tian M.,Huazhong University of Science and Technology | Lu P.,Huazhong University of Science and Technology | Chen L.,Huazhong University of Science and Technology | Liu D.,Huazhong University of Science and Technology | Yang M.,National Engineering Laboratory for Fiber Optic Sensing Technology
IEEE Photonics Technology Letters | Year: 2013

We propose and demonstrate a compact micromulticavity Fabry-Pérot (FP) optical fiber tip sensor for refractive-index (RI) and temperature measurement, which is fabricated by laser micromachining. The fabrication process of the sensor offers a quite simple way to fabricate compact in-line FP at a low cost. At the end of the single-mode fiber, there is a short air FP cavity, which forms a multicavity together with the fiber flat face tip. Two independent cavities exist in our sensor, and the air cavity is used for RI sensing and the glass cavity for temperature sensing, thus, avoiding the temperature and RI cross-sensitivity. The measurement results show that the in-line FPI exhibits an RI sensitivity of 1074.36 nm/RIU and a temperature sensitivity of 10.6 pm/°C. © 2013 IEEE.


Zhu F.-D.,National Engineering Laboratory for Fiber Optic Sensing Technology | Zhang D.-S.,National Engineering Laboratory for Fiber Optic Sensing Technology | Fan P.,National Engineering Laboratory for Fiber Optic Sensing Technology | Guo Y.-X.,National Engineering Laboratory for Fiber Optic Sensing Technology | And 2 more authors.
Guangdianzi Jiguang/Journal of Optoelectronics Laser | Year: 2014

In order to improve the sensing capacity of the FBG sensing system and the practical engineering viability and the future maintainability of the sensors, a new FBG sensing system with bus topological structure based on the optical frequency domain reflectometry (OFDR) technique has been proposed in this paper, and in this newly presented sensing system, the sensors multiplexing capacity and spatial resolution of the sensing system can be significantly enhanced by the employment of the OFDR technique. With this technique, the FBG sensors with the same wavelength have overcome the limitation brought by the impact of the bandwidth of the light source on the sensing capacity. Compared with the traditional system where the networking is cascaded by FBG with weak reflectivity, this newly proposed system with fiber Bragg grating has strong reflectivity and the optical branching device is applied so as to achieve bus topological structure for the FBG sensing system which can not only improve the viability of sensor but also overcome the impacts of multiple reflections and spectrum shadow occurring in the cascading FBG sensing network on measurement accuracy. The results of the temperature experiment show that the wavelength repeatability is ±4 pm.

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