The Fabrication And Signal Interrogation Technology Of High-temperature Resistant Long Period Fiber Grating

The Fiber grating technology has developed for over30years and widely used in the communication and sensing technology. The developing situation demand higher quality to fiber grating. For instance the fiber grating should work well in the environment of high temperature. The fiber Bragg grating has been maturity and the related technology has been used practically. The development and application of Long period fiber grating lags behind the fiber Bragg grating in the sensing technology. Although Long period fiber grating has a lot adventure such as higher sensitivity, no reflected light etc, the practical application degree falls behind fiber Bragg grating a lot, due to the defect of its manufacture and the signal interrogation. It will has obvious significance to do research on the two aspects. The specific research of this paper includes:1. A large number of reference were studied and the research status of high temperature fiber grating was introduced and LPFG was extracted; and then some fabrication methods technology of LPFG were analyzed and contrasted; and at last various methods on LPFG sensing signal interrogation were summarized and contrasted.2. The fabrication method of CO2laser pluses was adopted and a lot of LPFGs were fabricated. The method can be easily operate and with high efficiency. The LPFG which fabricated by the method has well high temperature resistance. On the basis of a lot of fabricated work some problems were exposed, such as hardly control to the LPFG spectrum, low concordance in repeat fabrication. Some reasons for bad effect to the fabrication result were analyzed and some suggestions were showed to help perfecting the method according to the experimental experience3. The experiments were designed to test the LPFG sensing property and the result of experiment was analyzed. The difficulties in the high temperature experiment was expounded, and then the method of using glass capillary to encapsulate LPFG and suspension was adopted to resolve the difficulties in the high temperature experiment. 4. On the basis of summary of LPFG sensing signal interrogation methods, the interrogation method based on F-P cavity was adopted to interrogate the LPFG sensing signal. The interrogation experimental platform was set up and the axial strain sensing signal and high temperature sensing signal were interrogated, and at last the experimental result was analyzed contrasted to the OSA.