Investigation On The Performance Degeneration Of Fiber Bragg Grating Sensor

Fiber Bragg Grating (FBG) has become one of the most rapid development passiveoptical fiber components since the90s. With many unique advantages, FBG sensorshave great application prospects in optical fiber communication and optical fiber sensorsystem. With the continuous improvement of the FBG manufacturing technology andthe growing applications, it is possible for FBG sensors to be employed in manycomplex optical fiber sensing networks and optical fiber communication systems. Thisgreatly expanded the optical fiber application fields.As the expanding FBG sensor applications, the long-term reliability and stability ofFBG sensors received more attentions. And because the FBG monitoring objects arealways servicing for long time and working at harsh environment, serious performancedegeneration of FBG sensors usually happened in practical applications. Accurateoriginal information can not be acquired due to the degeneration of FBG sensors, thatwill seriously interfere people to make a correct judgment and evaluation to the securitylevel and operational states of the monitoring objects. In order to estimate the FBG faultand master the FBG failure behavior completely. It is especially important to researchFBG sensors performance degeneration.Temperature and strain measurements are the main two purposes of FBG sensors.FBG performance degeneration will severely decay when they are working under hightemperature and alternating stress for a long term. This paper will research the heatleaded and stress leaded FBG sensor performance degeneration, respectively. Firstly,based on the dipole model of optical fiber photosensitive theory. The theoreticalexplanation of the heat caused FBG performance degeneration has been made and theequation of reflection peak decay along with the work time has been derived. Secondly,the alternating stress loading to the FBG sensors has been conducted to research thestress leaded degeneration. The FBG performance will be evaluated from the FBGsensing properties and also the reflective spectral quality.This paper is divided into five chapters. The first chapter introduced the FBGprinciple, the FBG development and the FBG applications. The paper research topichas been established through analyzing the current situation of the domestic andinternational researches on this topic.The second chapter introduced the FBG manufacturing and the FBG packaging technologies.In the third chapter. The theoretical explanation of the heat caused FBGperformance degeneration has been made and the relationship of reflection peak decayalong with the work time has been described. And the high temperature FBG decayexperiments have been conducted.In the fourth chapter, the stress leaded FBG performance degeneration has beeninvestigated through the alternating stress loading to FBG. FBG decay information hasbeen acquired and analyzed.In the final chapter, the work of this paper has been summarized and the futureresearch direction has been pointed out.