Research And Development Of An Applicable FBG Sensor Demodulation System

Fiber Bragg Grating (FBG) is one of the most potential and typical optical passive components. In 1978, the first FBG was written into a Ge-doped fiber by the method of standing-wave. From then on, because FBG has many unique characteristics, researchers worked hard on exploring its sensing application of different physical measurement, as well as the application in the field of optical communication. In recent years, more and more attention has been focused on the research and application of FBG sensor.As we can see from the research and application of FBG both domestic and overseas, there is little applicable achievement. The acquisition and process of sensing signal of FBG mainly rely on some optical instruments such as spectroscope. Up to now, there is no specialized analysis instrument for FBG sensor. Besides, in the known applications, the perceived physical quantum can not be obtained directly and say nothing of directly converting the wave length into electric codes and make it into use by other equipments such as control facility. It is no doubt a big obstacle to the wide application of FBG sensor.This paper is devoted to develop a wavelength demodulation system of distributed FBG sensor. It aims at engineering application of FBG sensor.In this paper, FBG and the theory of sensing with FBG are introduced systematically with the characteristics and applications of FBG sensor. The superiority of FBG sensor is that the sensing information is coded in the wavelength. Contrast study of some typical demodulation methods is made in this paper. And method of Fiber Fabry-Perot Tunable Filter (FFP-TF) is confirmed. It is of advantage to get a high sensitive wavelength displacement detection method with the features as high light efficiency, easy to be operated, inexpensive, and suitable for engineering application.As the basic method of demodulation is confirmed, this paper gives a demodulation solution detailed in system functions and requirements. The introduce of high-speed data acquisition card in the FFP-TF demodulation system of FBG sensor leads to a novel test system set up with this solution.Based on this novel system, this paper focuses on the development of anovel software system of demodulation, which named as "OptSensor". It integrates expandable support to the high-speed data acquisition cards. The structure design made it capable of real-time data collection, real-time analyzing with several methods and working offline as well. It realizes visual numerical output of the end result of demodulation.When the test system is set up and the development of OptSensor is accomplished, two experiments, displacement demodulation and temperature demodulation, are done to validate this solution. The tests indicate that the whole system is about to be ready for engineering application.