Design Of Digital Demodulation System For Fiber Bragg Grating Sensor

Fiber sensor for its safety, anti-magnetic interference, anti-corrosion, small size, high temperature, light weight, flexible and convenient has been widely used in sensor area. Moreover, fiber sensor can form neural network and complete become a reality of sensor network. With the development of modern production technology of fiber and integrated optical components, people can produce a variety of period and aperiodic grating in the fiber. Fiber Bragg grating (Fiber Bragg Grating, FBG) has been widely used in fiber communication systems, such as fiber laser, distributed feedback lasers, WDM system, fiber filters and dispersion compensators. For the special sensing properties of FBG, FBG has also widely used in fiber sensor system.This thesis designs a FBG sensor demodulation system based on tunable F-P filter, using self-designed filter driver circuit to control the tunable F-P filter, with NI6010 data acquisition card to collect the signal and LabVIEW programming to analyze and display the signal to verify the feasibility of the design. Then for the sampling rate, the system independence is not satisfied enough, so I used chip AD7266 and DAC811 to design an independent data acquisition module to realize a pair of channels of single-ended optical signal inputs, a pair of channels of differential optical signal inputs, a channel of ordinary single-ended signal input and a channel of ordinary pseudo-differential signal input. Each channel sampling rates up to 1MSPS, accuracy up to 12.5pm. Combined with embedded ARM development board realized the control of data acquisition module and the signal analysis, display and other functions, eventually completed a digital FBG sensor demodulation system.