Wentai Lin

Fiber-optic intrinsic distributed acoustic emission sensor for large structure health monitoring

A fiber-optic intrinsic distributed acoustic emission (AE) sensor is proposed. By measuring the time delay of two signals from two Mach-Zehnder interferometers, the location of AE can be deduced, and the corresponding sensor is experimentally verified to be feasible with a 206 m average location error in a 20 km sensing range, which shows that this proposed sensor is applicable for distributed AE sensing for large structure health monitoring, with the unique advantages of low cost, simple configuration, and long sensing range. The limitations of the proposed sensor are also discussed, and the future work is presented.

Review on Development and Applications of Fiber-Optic Sensors

Fiber-optic sensors (FOSs) have experienced a tremendous growth since the 1970s and a number of important transitions into commercial sector have been achieved. Due to the specific advantages, FOSs have been considered as not only the substitutes of conventional sensors but also the unique solution in fields of industry, engineering and scientific research itself. This paper provides a review on the concepts, principles, methodology and applications of FOSs. Firstly, the current state of the art of FOSs is reviewed. As significant cases of developments in FOSs,the interferometric sensors, fiber grating sensors, photo crystal fiber sensors and scattering based sensors are outlined, respectively. Furthermore, several potential areas, where FOS is believed to be the one and only effective solution, are also discussed. Finally, trends in the development of FOSs are briefly outlined by combine with development of photonics.

Distributed fiber optic perturbation locating sensor based on Dual-Mach-Zehnder interferometer

This paper studies a distributed fiber optic perturbation locating sensor used for security system, which is based on dual Mach-Zehnder interferometers. This system consists of two Mach-Zehnder interferometers with the common sensing arm, reference arm, two couplers and one laser source. This kind of distributed fiber optic perturbation locating sensor is very suitable for the measurement of the phase shift induced by some perturbation such as strain and vibration. When perturbation exerts on the sensing arm, a time delay will generate between the two output signals of the dual Mach-Zehnder interferometers. From the time delay, the location of the perturbation can be obtained. Experimenting on the type disturbances optic cable and forcing on the 18.46km long distance fiber, the system correctly shows the position for real time and the average error is 390m. The experiment shows that the system can be applicable for locating on 40km distance fiber cable when the power of the laser resource increases to 300μW.