Fiber Grating Sensor System Based On CDMA Technology

Fiber bragg grating (FBG) sensor is widely used in the field of sensing, for its corrosion resistance, anti-electromagnetic interference, easy composition of distributed sensoring networks, wavelength coding etc. However, several sensors simultaneous working is necessary in many engineering applications and common multiplexing technology is limited by some cases like the bandwidth of laser source and the power of laser source.The fiber grating sensoring system based on CDMA(Code Division Multiple Access) doesn’t use Fabry-Perot filter for scanning wavelengths and reduces cost. The fiber grating sensoring system sends coding sequences, utilizes correlation to demodulate and improves signal to noise ratio. A fiber grating sensoring system is investigated by using CDMA technology based on analyzing principle of demodulation technique for FBG.Firstly, the paper describes the principle of FBG sensor, the FBG sensing characteristics of temperature and strain and some kinds of demodulation and multiplexing technologies. We investigate a FBG sensor network based on the code division multiple access (CDMA) technology.Secondly, we investigate a FBG sensor network based on the code division multiple access (CDMA) technology by using Golay complementary code. Meanwhile, a FBG sensing demodulation system and related software is developed to realize the real-time monitoring.Finally, to verify the performance and stability of the software system, an experiment about temperature sensing is conducted. Meanwhile, we investigate how the pulse width and code length influences the sensitivity and SNR of the system. The experimental results show that the system has high sensitivity,good repeatability and low crosstalk. So it’s of great significance for quasi-distributed Fiber Bragg Grating sensing system.