Study Of A New-style Liquid Refractive Index Sensor Based On Tapered Optical Fiber With A Micro-hole

With the development of science and technology, it is more and more importantfor human to use of sensor’s ability to get all kinds of information, so research hasbecome a focus of various sensor sensitivity and tapered fiber optic sensor for itssimple operation, femtosecond laser technology for its extremely narrow pulse width,high temporal resolution, the characteristics of high peak power has been widely used.Welding mechanism is used as the cone glass fiber, this paper made a femtosecondlaser drilling technology is a new type of liquid refractive index sensors with a holeon tapered glass fiber, focuses on the sensitivity of the sensor and the position of conearea and pore diameter.Firstly, we analyzed by using ray theory of meridional ray in tapered optical fibertransmission, and got light power transmission loss of the tapered optical fiber sensorwith the outside world the liquid refractive index increases. Experiment selectedrespectively15μm,20μm and27μm three different tapered fiber in diameter, usingstate of the sensing system to measure the loss, getting the cone of15μm in diametertaper fiber optic sensor has the highest sensitivity, reached16dB/RIU (refractiveindex unit). So tapered fiber optic sensor sensitivity mainly is closely related to theoptical fiber taper, namely cone diameter of the tapered optical fiber is smaller, thehigher the sensitivity of the sensor. So in order to get higher sensitivity of taperedfiber optic sensor, we will need to pull fiber into long thin filaments, but glass fiberqualitative fragile easy to fold, so in this paper, we put forward a new liquid refractiveindex sensor with a micro-hole in tapered single-mode fiber. The hole in this sensorwas mainly used to realize the power transfer between the fiber core and cladding,avoided with slender cone of the purpose of enhancing core covering power transfer. The sensor has many advantages, such as good linearity measurement, easy operation,large measuring range, easy operation, etc.In this paper, we using ray theory analyze the meridional ray transmission insingle-mode fiber glass liquid refractive index sensor characteristics, draw a timesensor light power transmission loss also increases with the increase of outside liquidrefractive index. Experiment selected the cone area of30μm in diameter taper fiber,are connected to the cone area in the isosceles distance30μm,60μm,100μmrespectively make a sealed hole, measurement of30μm sensor has the highestsensitivity, so we choose a sealed hole in a join point, measuring found the resultcompletely conforms to the theoretical analysis, and the sensitivity of up to70dB/RIU.