Manufacturing Technique And Applications Research Of Optical Fiber Sensors

Optical Fiber Sensors have attracted great interest in recent years because of itsunique advantages in sensor applications, such as high sensitivity, integration,networking and immunity to electromagnetic interference. Nowadays, optical fibersensing systems have functioned very well. This paper mainly explores the opticalfiber sensors fabrication process, commercial sensors sensitivity testing and sensingsystem establishing with the following contents and innovations:(1) This study proposes a high-sensitivity Mach-Zehnder(MZ) interferometricrefractive index(RI) sensor based on two different ultra-abrupt tapers is proposed anddemonstrated experimentally. The whole fabrication process is relatively simple. Onetaper is fabricated by the fusion-splicing method and the ratio of the waist diameter tothe taper length is1:1. The other taper is fabricated by CO2laser irradiation with aratio around1:10. According to the experimental results, the spectral loss of theproposed MZ interferometric sensor has a linear response to the external RI changewith a ultrahigh sensitivity of-412.02138dB/RIU(refractive index unit) in the rangeof1.3505-1.3684. A MZ interferometric sensor based on two core-offset attenuatorsand an abrupt taper in a single-mode fiber is fabricated by electric arc discharge and afiber taper machine. When the distance between the two core-offset attenuators isstretched by4500μm, distinct interference signals can be detected with a prominentattenuation peak of~28dB. According to the test results, its temperature sensitivity is34.95pm/℃and106.7pm/℃in the temperature ranges of15℃-250℃and250℃-1000℃, respectively.(2) This study proposes three vibration sensors based on optical fiber Bragggratings(FBG), being called simply supported beam FBG vibration sensor,cantilever beam FBG vibration sensor and single particle FBG vibration sensor,respectively. The function, composition and working principle of the fiber gratingvibration sensor are introduced, and a perimeter intrusion alarm system can be built based on the vibration sensor. The system integrate sound and light alarm module,closed circuit television module and SMS alarm module.(3) This study introduces a multi-liquid-parameter monitoring system and aperimeter intrusion alarm system, both based on optical fiber sensor. Themulti-liquid-parameter monitoring system includes laser rangefinders, optical FBGtemperature sensors, optical fiber Fabry-Pérot(F-P) interferometric pressure sensorsand optical fiber Fabry–P é rot(F-P) interferometric RI sensors. The perimeterintrusion alarm system includes the vibration sensors part and dual M-Zinterferometer part, applied to the small scale monitoring and the grand areamonitoring. This paper also expounds the principles and communication modes oftwo systems. Furthermore, two systems can carry out the real-time and on-linemonitoring, and have significant advantages compared with the traditional method.