"DISCRIMINATION OF TEMPERATURE AND STRAIN INTERFERENCE IN FBG SENSORS USING TAPERED OPTICAL FIBER SENSOR "

Abstract

"The optical fiber industry has progressed a lot in recent years. Earlier, they were used as a bed to carry light and image for medical applications, especially in endoscopy. In the mid-1960s, calls were widely used to transmit information. So far, optical fiber technology has been a worthy subject for research. Low loss rate, high bandwidth, electromagnetic reliability, small size, light weight, safety, relatively cheap price, low need for reconstruction and maintenance are the reasons for the attractiveness of optical fibers. In recent years, optical sensors, including FBG, are widely used in the field. Different methods have been used. Among these applications, we can refer to imaging in the fields of civil engineering, aerospace, marine sciences, oil and gas, composites and smart structures. Fiber Bragg Grating (FBG) sensors have found more usages in the industry to diagnose the safety of mechanical structures due to their high sensitivity, non-exposure to the electromagnetic field, linearity, and lightness. A limitation of the application of FBG sensors is the Inability to distinguish the effects of temperature and strain in the simultaneous measurement. For this purpose, we must somehow discriminate the effect of temperature from the strain. In this Article, by designing a tapered fiber-FBG composite sensor we have provided a solution for this problem. Studies performed on the designed composite sensor show that no sensitivity interference will occur in the sensor. In the composite sensor, a tapered fiber optic sensor with a temperature sensitivity of and a FBG sensor with the temperature and strain sensitivity of and, respectively, are used. Keywords: Tapered fiber, Temperature sensor, FBG sensor, Strain health monitor, Structural health monitor, Interferences. "