Study On The Computer Information Process System Of The New Demodulation Method Of Multiple FBG Sensors

FBG sensor is one of the current heat research fields in the optical fiber grating sensoring technique fields. It is widely applied in many fields such as the structure monitoring of the large compound material and the concrete, the performance monitoring of the intelligent materials, electric power industry, medicine, chemical engineering etc. The demodulation technique of the FBG is currently a critical and difficult problem in nowadays FBG sensoririg technique fields. Although a large number of researchers in domestic research units have been doing a lot of research and investigations on the demodulation methods of FBG, most of the researches are still in the phase of lab experiments and have not yet met the requirements of the practical industrial mass productions.In this paper, a high-resolution, cheap, easy-to-operate, distributed FBG wavelength demodulation system is presented. This system can meet the requirements of the practical industrial applications and display the real-time changes of measurands. In this system, a tunable fiber Fabry-Perot(F-P) filter is used to detect the changes of the wavelengths of the FBGs, then both the tunable control signal and the signal indicating the changes of the wavelength transmitted by an A/D electric transmission circuit are input into a high speed sampling card. The corresponding changes of the measurands can be obtained by filtering, analysising and processing the experimental data by using the computer information process system.Firstly, this paper deals with the theoretical feasibility of the demodulation scheme and its performance and then clarifies the scheme in details. Secondly, experiments are performed to testify the resolution of the system and analysis of the results is made. Finally, approach to improve the performance of the system is put forwards based on the analysis of the experimental results. The following work has been done in this paper:l.have put forward an integrated distributed FBG sensoring demodulation system and have settled the whole set of equipments and experimental devices of the system. Software corresponding to a 8-byte and a 16-byte sampling card have been developed respectively. The main functions of the software include collection and process of the data, analysis can also be made by using the software.2.Based on the collection and analysis of the experimental results, thesoftware system has been improved and an 8-byte sampling card is applied to testify the feasibility of the designed system. The system resolutions of the two measurands-temperature and strain-have been obtained by using a 16-byte sampling card. The distributed demodulation function is also testified.3. Have analyzed the possible factors causing errors between the theoretical performance and the actual data and an approach to improved the demodulation scheme is proposed.